(a) Except as covered in Bulletin 345-3, no loan funds shall be advanced for any product if any item to be included in the project is not included in the “List of Materials Acceptable for Use on Telephone Systems of RUS Borrowers,” RUS Bulletin 344-2. When new items of materials or equipment are considered for acceptance by RUS or when a previously accepted item has been subjected to such major modifications that its suitability cannot be determined based on laboratory data and/or field experience, a field trial shall be required if RUS so determines. This field trial consists of limited field installations of the materials or equipment in closely monitored situations designed to determine, to RUS's satisfaction, their operational effectiveness under actual field conditions. Field trials are to be used only as a means for determining, to RUS's satisfaction, the operational effectiveness of a new or revised product under actual field conditions. Both the manufacturer and borrower are responsible for assuring that the field trial is carried out and that the required information on the product's performance is received by RUS in a timely manner. The use of materials or equipment derived from new inventions or concepts untried within the telephone industry is defined as “an experiment” and shall be handled as a special case using procedures considered appropriate by RUS to meet the individual experiment.

(b) To qualify for a field trial, the new and improved materials and equipment must appear to RUS to offer one or more of the following benefits:

(1) Improved performance.

(2) Decreased cost.

(3) Broader application.

(c) The item of material or equipment subject to field trial may be only part of the total amount of materials or equipment included in a bid or it may be the key component of the facility or system provided; therefore, RUS shall have authority to require that a satisfactory plan be provided to maintain or restore service in the event that the materials and equipment fail to meet established performance requirements. RUS shall limit the quantity of new materials and equipment installed on any field trial and shall also limit the number of field trials for a given product to what RUS considers reasonable to provide the necessary information.

(d) A borrower may participate in a field trial only if, in RUS's opinion, the borrower possesses:

(1) Adequate financial resources so that no delay in the project will result from lack of funds.

(2) The financial stability to overcome difficulties which may result from an unsuccessful field trial. The borrower must be able to restore and maintain service until the manufacturer meets its financial obligations with respect to the field trial.

(3) Qualified personnel to enable it to discharge its responsibilities.

(4) A record satisfactory to RUS for maintaining equipment and plant facilities and for providing RUS with information when requested.

(5) Willingness to participate in the field trial and awareness of the effort and responsibility this entails.

(e) The test site for the field trial shall be, in RUS's opinion, readily accessible and provide the conditions, such as temperature extremes, high probability of lightning damage, etc., for which the product is being evaluated. The material or equipment involved shall be covered by an RUS specification or a suitable standard acceptable to RUS. The supplier is required to submit test data to show conformance with the applicable specification or standard. Further testing shall be performed if required by RUS personnel.

(f) A field trial shall normally continue for a minimum of six months, or for a longer period of time determined by RUS to be required to obtain conclusive data that the item either fulfills all requirements or is unacceptable. Either the borrower or supplier may terminate a field trial at any time, in accordance with their contractual agreement. Such termination, if prior to the time required by RUS, shall constitute withdrawal of the product from consideration by RUS. RUS has authority to terminate field trials based on its determination that the equipment is not performing satisfactorily and that this lack of performance may, in RUS's opinion, cause service degradation or hazards to life or property.

(g) Field trials shall be conducted in accordance with the instructions set forth in this regulation and the agreement relating to the specific application. Both the supplier and the borrower shall agree, and obtain RUS approval before the start of the trial, on the following:

(1) The specific purpose of the field trial;

(2) Ownership of items during trial;

(3) Starting date and duration;

(4) Responsibility for costs and removal of items in the event of noncompliance with the specification or purpose intended and arrangements for service continuity or restoration;

(5) Responsibility for testing, test equipment and normal operation and maintenance during the trial period;

(6) Availability of test equipment on site during the trial period; and

(7) Responsibility for spare parts and components consumed during the trial period.

(h) Both the supplier and the borrower shall keep RUS informed of the status of a field trial. These reports shall not be limited to details of problems of failures encountered during installation and subsequent operation but shall include information on progress of the field trial. If these reports are not received in accordance with the requirements of the RUS Form 399b, RUS shall have the authority to deny or suspend loan funds related to these products until the delinquent reports are received.

(i) Before a borrower purchases materials or equipment that require a field trial, prior approval must be obtained from RUS and RUS Form 399b, RUS Telecommunications Equipment Field Trial (available from the Director, Administrative Services Division, Rural Utilities Service, Room 0175, South Building, U.S. Department of Agriculture, Washington, DC 20250) will be completed by RUS and must be signed by both the borrower and supplier as an indication that they understand their responsibilities in the field trial. Assurance must also be obtained from RUS that the “particular item” that is the subject of the field test is eligible for a field trial. To obtain this assurance, any proposal for use of an item on a field trial basis shall be forwarded to the Chief, Area Engineering Branch, for review and approval.

(j) Procedures for establishing field trials for the various categories of equipment after RUS has approved the 399b:

(1) Electronic transmission equipment. The procedure set forth in Bulletin 385-2 “Purchasing and Installing Special Electronic Equipment” shall be followed except that the Special Equipment Contract (Including Installation), RUS Form 397, shall be used in all purchases of electronic equipment for field trials. In addition, the borrower and supplier shall execute three copies of a “Supplemental Agreement to Equipment Contract for Field Trial,” RUS Form 399, or a “Supplemental Agreement to Equipment Contract for Field Trial (Secondary—Delivery, Installation, Operation)”, RUS Form 399a, as well as three copies of the RUS Form 399b, “RUS Telecommunications Equipment Field Trial”, and forward them, together with three copies of the executed contract and specifications, to the Chief, Area Engineering Branch. A limited number of copies of RUS Forms 399, 399a, and 399b are available from RUS upon request from the Director, Administrative Services Division, Rural Utilities Service, Room 0175, South Building, U.S. Department of Agriculture, Washington, DC 20250. Additional copies may be reproduced by the user as needed. This category includes:

(i) Voice frequency repeaters;

(ii) Trunk carriers;

(iii) Subscriber carrier;

(iv) Point-to-point radio (Microwave);

(v) Coaxial cable system electronics;

(vi) Fiber optic cable system electronics;

(vii) Multiplex equipment;

(viii) Mobile and fixed radiotelephone; and

(ix) Other items of electronic equipment associated with transmission.

(2) Central office equipment. The procedure set forth in Bulletin 384-1 “Purchasing and Installing Central Office Equipment” shall be followed except that “The Central Office Equipment Contract (Including Installation)”, RUS Form 525, shall be used to purchase switching equipment for field trials. In addition, the borrower and supplier shall execute three copies of a “Supplemental Agreement to Equipment Contract for Field Trial,” RUS Form 399, or a “Supplemental Agreement to Equipment Contract for Field Trial (Secondary—Delivery, Installation, Operation)”, RUS Form 399a, as the case may be, as well as three copies of the RUS Form 399b, “RUS Telecommunications Equipment Field Trial”, and forward them, together with three copies of the executed contract and specification to the Chief, Area Engineering Branch. This category includes:

(i) Central office dial equipment;

(ii) Direct distance dialing equipment;

(iii) Automatic number identification equipment;

(iv) Line concentrators;

(v) Remote switching equipment; and

(vi) All other items of equipment associated with switching equipment, such as loop extenders.

(3) Protection equipment and materials, outside plant equipment and materials, and all other equipment and materials, which includes all items not covered in paragraph (j) (1) or (2) of this section, shall be handled as described in Bulletin 344-1 “Methods of Purchasing Materials and Equipment for Use on Systems of Telephone Borrowers” except that the borrower's purchase order form is to be used for purchasing materials and equipment in these categories. In addition, the borrower and supplier shall execute three copies of the “Supplemental Agreement to Equipment Contract for Field Trial,” RUS Form 399, or a “Supplemental Agreement to Equipment Contract for Field Trial (Secondary—Delivery, Installation, Operation)”, RUS Form 399a, as the case may be, as well as three copies of the RUS Form 399b, “RUS Telecommunications Field Trial”, and forward them, together with three copies of the purchase order to the Chief, Area Engineering Branch.

(k) For all items except Electronic Central Office Equipment, suppliers and manufacturers must furnish warranties or guarantees satisfactory to RUS against the failure of the material and equipment used in the field trial. Terms of this warranty must not be less than the provisions of the standard warranty included in the “Telephone System Construction Contract”, RUS Form 515, or the warranty provided for similar materials and equipment included in the “List of Materials Acceptable for Use on Telephone Systems of RUS Borrowers”, RUS Bulletin 344-2. In lieu of a warranty, materials and equipment are sometimes furnished to RUS borrowers on a reduced or no cost basis. Terms of such arrangements are subject to RUS approval and should be fully covered in field trial proposals forwarded by borrowers to the Chief, Area Engineering Branch for review and approval. For the purchase of electronic central office equipment, suppliers and manufacturers are to provide warranties as provided in the applicable RUS contract form: RUS Form 397 for electronic equipment and RUS Form 525 for central office equipment. Forms 399 and 399a, which apply to field trials of these devices, specify that the term of the warranty does not begin until the satisfactory conclusion of the field trial.

[49 FR 28394, July 12, 1984. Redesignated at 55 FR 39397, Sept. 27, 1990]

(a) The standard loan agreement between RUS and its borrowers provides that, in accordance with applicable RUS regulations, borrowers shall use standard contract forms promulgated by RUS for construction, procurement, engineering services, and architectural services financed by a loan or guaranteed by RUS. This part implements these provisions of the RUS loan agreement and prescribes the procedures that RUS follows in promulgating standard contract forms that borrowers are required to use. Part 1753 prescribes when and how borrowers are required to use these standard forms of contracts.

(b) Contract forms. RUS promulgates standard contract forms, identified in § 1755.30(c), List of Standard Contract Forms, that borrowers are required to use.

[64 FR 6500, Feb. 10, 1999]

(a) Loan agreement. As a condition of a loan or loan guaranteed under the RE Act, borrowers are normally required to enter into RUS loan agreements pursuant to which the borrowers agree to use RUS standard contract forms for construction, procurement, engineering services, and architectural services financed in whole or in part by the RUS loan. To comply with the provisions of the loan agreements as implemented by this part, borrowers must use those contract forms identified in the list of telecommunications standard contract forms, set forth in § 1755.30(c) of this part.

(b) Compliance. (1) If a borrower is required by part 1753 to use a listed contract form, the borrower shall use the listed contract form in the format available from RUS. The forms shall not be retyped, changed, modified, or altered in any manner not specifically authorized in this part or approved by RUS in writing. Any modifications approved by RUS must be clearly shown so as to indicate the difference from the listed contract form.

(2) The borrower may use electronic reproductions of a contract form if the contract documents submitted for RUS approval are exact reproductions of the RUS form and include the following certification by the borrower: I (Insert name of the person.), certify that the attached (Insert name of the contract form.), between (Insert name of the parties.), dated (Insert contract date.) is an exact reproduction of RUS Form (Insert form number), dated (Insert date of RUS form).

(Signature) (Title) (Employer's Address)

(c) Amendment. Where a borrower has entered into a contract in the form required by 7 CFR part 1753, no change may be made in the terms of the contract, by amendment, waiver or otherwise, without the prior written approval of RUS.

(d) Waiver. RUS may waive for good cause, on a case-by-case basis, the requirements imposed on a borrower pursuant to this part. Borrowers seeking an RUS waiver must provide RUS with a written request explaining the need for the waiver.

(e) Violations. A failure on the part of the borrower to use listed contracts as prescribed in 7 CFR part 1753 is a violation of the terms of the loan agreement with RUS and RUS may exercise any and all remedies available under the terms of the agreement or otherwise.

[64 FR 6500, Feb. 10, 1999]

(a) Notice. Upon initially entering a loan agreement with RUS, borrowers will be provided with all listed contract forms. Thereafter, new or revised listed contract forms promulgated by RUS, including RUS approved exceptions and alternatives, will be sent by regular or electronic mail to the borrower's address as identified in its loan agreement with RUS.

(b) Availability. Listed contract forms are published by RUS. Interested parties may obtain the forms from the Rural Utilities Service, Program Development and Regulatory Analysis, U.S. Department of Agriculture, Stop 1522, Washington DC 20250-1522, telephone number (202) 720-8674. The list of contract forms can be found in § 1755.30(c).

[64 FR 6500, Feb. 10, 1999]

RUS may, from time to time, promulgate new contract forms or revise or eliminate existing contract forms. In so doing, RUS shall publish a notice of rulemaking in the Federal Register announcing, as appropriate, a revision in, or a proposal to amend § 1755.30(c), List of telecommunications standard contract forms. The amendment may change the existing identification of a listed contract form by, for example, changing the issuance date of the listed contract form or identifying a new required contract form. The notice of rulemaking will describe the new standard contract form or substantive change in the listed contract form, as the case may be, and the issues involved. The standard contract form or relevant portions thereof may be appended to the supplementary information section of the notice of rulemaking. As appropriate, the notice of rulemaking shall provide an opportunity for interested persons to provide comments. RUS shall send, by regular or electronic mail, a copy of each such Federal Register document to all borrowers.

[64 FR 6500, Feb. 10, 1999]

(a) General. The following is a list of RUS telecommunications program standard contract forms for procurement, construction, engineering services, and architectural services. Borrowers are required to use these contract forms by the terms of their RUS loan agreements implemented by part 1753 and this part.

(b) Issuance Date. Where part 1753 requires the use of a standard contract form in connection with RUS financing, the borrower shall use the appropriate form identified in § 1755.30(c), List of Telecommunications Standard Contract Forms, published as of the date the borrower releases the plans and specifications to solicit bids or price quotes.

(c) List of telecommunications standard contract forms. (1) RUS Form 157, issued 10-77, Construction Work Plan and cost Distribution—Telephone.

(2) RUS Form 158, issued 10-77, Certification of Contract or Force Account Approval.

(3) RUS Form 159, issued 10-77, Summary of Completed Construction.

(4) RUS Form 168b, issued 2-04, Contractor's Bond.

(5) RUS Form 168c, issued 2-04, Contractor's Bond.

(6) RUS Form 181a, issued 3-66, Certificate of Completion (Force Account Construction).

(7) RUS Form 187, issued 2-04, Certificate of Completion, Contract Construction.

(8) RUS Form 213, issued 2-04, Certificate (Buy American).

(9) RUS Form 216, issued 7-67, Construction Change Order.

(10) RUS Form 217, issued 3-97, Postloan Engineering Services Contract—Telecommunications Systems.

(11) RUS Form 220, issued 6-98, Architectural Services Contract.

(12) RUS Form 224, issued 2-04, Waiver and Release of Lien.

(13) RUS Form 231, issued 2-04, Certificate of Contractor.

(14) RUS Form 238, issued 2-04, Construction or Equipment Contract Amendment.

(15) RUS Form 242, issued 11-58, Assignment of Engineering Service Contract.

(16) RUS Form 245, issued 11-75, Engineering Services Contract, Special Services—Telephone.

(17) RUS Form 257, issued 2-04, Contract to Construct Buildings.

(18) RUS Form 257a, issued 10-69, Contractor's Bond.

(19) RUS Form 274, issued 6-81, Bidder's Qualifications.

(20) RUS Form 276, issued 5-59, Bidder's Qualifications for Buried Plant Construction.

(21) RUS Form 281 issued 5-61, Tabulation of Materials Furnished by Borrower.

(22) RUS Form 282, issued 11-53, Subcontract (Under Construction or Equipment Contracts).

(23) RUS Form 284, issued 4-72, Final Statement of Cost for Architectural Service and Certificate of Architect.

(24) RUS Form 307, issued 2-04, Bid Bond.

(25) RUS Form 395, October 18, 2016, Equipment Contract.

(26) RUS Form 395a, October 18, 2016, Equipment Contract Certificate of Completion (Including Installation).

(27) RUS Form 395b, October 18, 2016, Equipment Contract Certificate of Completion (Not Including Installation).

(28) RUS Form 395c, October 18, 2016, Certificate of Contractor and Indemnity Agreement.

(29) RUS Form 395d, October 18, 2016, Results of Acceptance Tests.

(30) RUS Form 506, issued 3-97, Statement of Engineering Fee—Telecommunications.

(31) RUS Form 515, issued September 17, 2001, Telecommunications Systems Construction Contract (Labor and Materials).

(32) RUS Form 526, issued 8-66, Construction Contract Amendment.

(33) RUS Form 527, issued 3-71, Statement of Construction, Telephone System “Outside Plant”.

(34) RUS Form 553, issued 5-67, Check List for Review of Plans and Specifications.

(35) RUS Form 724, issued 10-63, Final Inventory, Telephone Construction Contract.

(36) RUS Form 724a, issued 4-61, Final Inventory, Telephone Construction—Telephone Construction Contract (Labor and Materials), columns 1-8.

(37) RUS Form 724b, issued 3-61, Final Inventory, Telephone Construction Contract (Labor and Materials), columns 9-14.

(38) RUS Form 771, issued 10-75, Summary of Work Orders (Inspected by RUS Field Engineer).

(39) RUS Form 771a, issued 10-75, Summary of Work Orders (Inspected by Licensed Engineer or Borrower's Staff Engineer).

(40) RUS Form 773, issued 12-90, Miscellaneous Construction Work and Maintenance Services Contract.

(41) RUS Form 787, issued 8-63, Supplement A to Construction Contract.

(42) RUS Form 817, issued 6-60, Final Inventory, Telephone Force Account Construction.

(43) RUS Form 817a, issued 6-60, Final Inventory, Telephone Force Account Construction, columns 1-8.

(44) RUS Form 817b, issued 6-60, Final Inventory, Telephone Force Account Construction, Columns 9-14.

(45) RUS Form 835, issued 3-66, Preloan Engineering Service Contract, Telephone System Design.

[64 FR 6501, Feb. 10, 1999, as amended at 64 FR 53887, Oct. 5, 1999; 65 FR 51750, Aug. 25, 2000; 69 FR 7111, Feb. 13, 2004; 81 FR 71585, Oct. 18, 2016]

(a)(1) Certain material is incorporated by reference into this part with the approval of the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This material is available for inspection at the Rural Utilities Service (RUS) and at the National Archives and Records Administration (NARA). Contact the RUS at: 1400 Independence Ave. SW, Washington, DC, 202-692-0042; email: [email protected]; Telephone number: 202-692-0042; https://www.rd.usda.gov/resources/regulations/bulletins. For information on the availability of this material at NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html. The material may be obtained from the following source(s):

(2) To comply with the provisions of this part, you must follow the requirements set out in the RUS telecommunications bulletins incorporated by reference. These materials are incorporated as they exist on the date of the approval and notification of any change in these materials will be published in the Federal Register. The terms “RUS form”, “RUS standard form”, “RUS specification”, and “RUS bulletin” have the same meaning as the terms “REA form”, “REA standards form”, “REA specification”, and “REA bulletin”, respectively, unless otherwise indicated. For information on other standards incorporated by reference into this part see § 1755.901.

(b) Rural Utilities Service, U.S. Department of Agriculture, Room 5170-S, U.S. Department of Agriculture, Washington, DC 20250, https://www.rd.usda.gov/publications/regulations-guidelines/bulletins.

(1) Bulletin 345-39, RUS specification for telephone station protectors, August 19, 1985.

(2) Bulletin 345-50 PE-60, RUS specification for trunk carrier systems, September 1979.

(3) Bulletin 345-54 PE-52, RUS specification for telephone cable splicing connectors, December 1971.

(4) Bulletin 345-55 PE-61, RUS specification for central office loop extenders and loop extender voice frequency repeater combinations, December 1973.

(5) Bulletin 345-65, PE-65, Specification for shield bonding connectors, March 22, 1985.

(6) Bulletin 345-66 PE-64, RUS specification for subscriber carrier systems, September 1979.

(7) Bulletin 345-69 PE-29, RUS specification for two-wire voice frequency repeater equipment, January 1978.

(8) Bulletin 345-72 PE-74, RUS specification for filled splice closures, October 1985.

(9) Bulletin 345-78 PE-78, RUS specification for carbon arrester assemblies for use in protectors, February 1980.

(10) Bulletin 345-180 Form 397a, RUS specifications for voice frequency repeaters and voice frequency repeatered trunks, January 1963.

(11) Bulletin 345-183 Form 397d, RUS design specifications for point-to-point microwave radio systems June 1970.

(12) Bulletin 345-184 Form 397e, RUS design specifications for mobile and fixed dial radio telephone equipment May 1971.

(13) Bulletin 1728F-700, RUS Specification for Wood Poles, Stubs and Anchor Logs, April 18, 2022.

(14) Bulletin 1753F-150 Form 515a, Specifications and Drawings for Construction of Direct Buried Plant, September 30, 2010.

(15) Bulletin 1753F-151 Form 515b, Specifications and Drawings for Construction of Underground Plan, September 12, 2001.

(16) Bulletin 1753F-152 Form 515c, Specifications and Drawings for Construction of Aerial Plant, September 17, 2001.

(17) Bulletin 1753F-153 Form 515d, Specifications and Drawings for Service Installation at Customer Access Locations, September 17, 2001.

[84 FR 28201, June 18, 2019, as amended at 86 FR 57022, Oct. 14, 2021; 87 FR 26963, May 6, 2022]

The following specifications are included throughout 7 CFR chapter XVII. These specifications are not incorporated by reference elsewhere in the chapter. The terms “RUS form,” “RUS standard form,” “RUS specification,” and “RUS bulletin” have the same meaning as the terms “REA form,” “REA standard form,” “REA specification,” and “REA bulletin,” respectively, unless otherwise indicated. The list of specifications follows:

[55 FR 39397, Sept. 27, 1990, as amended at 84 FR 28201, June 18, 2019; 86 FR 57022, Oct. 14, 2021; 87 FR 26963, May 6, 2022]

(a) Scope. (1) This section describes approved methods for splicing plastic insulated copper and fiber optic cables. Typical applications of these methods include aerial, buried, and underground splices.

(2) American National Standard Institute/National Fire Protection Association (ANSI/NFPA) 70, 1993 National Electrical Code (NEC) referenced in this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. A copy of the ANSI/NFPA 1993 NEC standard is available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from NFPA, Batterymarch Park, Quincy, Massachusetts 02269, telephone number 1 (800) 344-3555.

(3) American National Standard Institute/Institute of Electrical and Electronics Engineers, Inc. (ANSI/IEEE), 1993 National Electrical Safety Code (NESC) referenced in this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. A copy of the ANSI/IEEE 1993 NESC standard is available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from IEEE Service Center, 455 Hoes Lane, Piscataway, New Jersey 08854, telephone number 1 (800) 678-4333.

(b) General. (1) Only Rural Utilities Service (RUS) accepted filled cable and splicing materials shall be used on outside plant projects financed by RUS.

(2) The installation instructions provided by the manufacturer of splicing materials shall be followed except where those instructions conflict with the procedures specified in this section.

(3) Precautions shall be taken to prevent the ingress of moisture and other contaminants during all phases of the splicing installation. When an uncompleted splice must be left unattended, it shall be sealed to prevent the ingress of moisture and other contaminants.

(4) Minor sheath damage during construction may be repaired if the repair is completed immediately and approved by the borrower's resident project representative. Minor damage is typically repaired by:

(i) Scuffing the cable sheath associated with the damaged area;

(ii) Applying several layers of DR tape over the scuffed and damaged area;

(iii) Applying several layers of plastic tape over the DR tape; and

(iv) If damage is severe enough to rupture the cable shield, a splice closure shall be installed.

(5) All splice cases installed on RUS toll trunk and feeder cables shall be filled, whether aerial, buried, or underground.

(c) Splicing considerations for copper cables—(1) Preconstruction testing. It is desirable that each reel of cable be tested for grounds, opens, shorts, crosses, and shield continuity before the cable is installed. However, manufacturer supplied test results are acceptable. All cable pairs shall be free from electrical defects.

(2) Handling precautions. The cable manufacturer's instructions concerning pulling tension and bending radius shall be observed. Unless the cable manufacturer's recommendation is more stringent, the minimum bending radius shall be 10 times the cable diameter for copper cables and 20 times the cable diameter for fiber optic cables.

(3) Cable sheath removal. (i) The length of cable sheath to be removed shall be governed by the type of splicing hardware used. Follow the splice case manufacturer's recommendations. For pedestals or large pair count splice housings, consider removing enough cable sheath to allow the conductors to extend to the top of the pedestal and then to hang downward to approximately 15 centimeters (cm) (6 inches (in.)) above the baseplate.

(ii) Caution shall be exercised to avoid damaging the conductor insulation when cutting through the cable shield and removing the shield. Sharp edges and burrs shall be removed from the cut end of the shield.

(4) Shield bonding and grounding. For personnel safety, the shields of the cables to be spliced shall be bonded together and grounded before splicing activities are started. (See paragraphs (g)(2), and (g)(5)(i) through (g)(5)(iii) of this section for final bonding and grounding provisions.)

(5) Binder group identification. (i) Color coded plastic tie wraps shall be placed loosely around each binder group of cables before splicing operations are attempted. The tie wraps shall be installed as near the cable sheath as practicable and shall conform to the same color designations as the binder ribbons. Twisted wire pigtails shall not be used to identify binder groups due to potential transmission degradation.

(ii) The standard insulation color code used to identify individual cable pairs within 25-pair binder groups shall be as shown in Table 1:

(iii) The standard binder ribbon color code used to designate 25-pair binder groups within 600-pair super units shall be as shown in Table 2:

(iv) Super-unit binder groups shall be identified in accordance with Table 3:

(v) Service pairs in screened cables shall be identified in accordance with Table 4:

(6) Cleaning conductors. It is not necessary to remove the filling compound from cable conductors before splicing. However, it is permissible to wipe individual conductors with clean paper towels or clean cloth rags. No cleaning chemicals, etc., shall be used. Caution shall be exercised to maintain individual cable pair and binder group identity. Binder group identity shall be maintained by using color coded plastic tie wraps. Individual pair identification shall be maintained by carefully twisting together the two conductors of each pair.

(7) Expanded plastic insulated conductor (PIC) precautions. Solid PIC and expanded (foam or foam skin) PIC are spliced in the same manner, using the same tools and materials and, in general, should be treated the same. However, the insulation on expanded PIC is much more fragile than solid PIC. Twisting or forming expanded PIC into extremely compact splice bundles and applying excessive amounts of tension when tightening tie wraps causes shiners and, thus shall be avoided.

(8) Splice connectors. (i) Only RUS accepted filled splice connectors shall be used on outside plant projects financed by RUS.

(ii) Specialized connectors are available for splicing operations such as butt splices, in line splices, bridge taps, clearing and capping, and multiple pair splicing operations. The splice connector manufacturer's recommendations shall be followed concerning connector selection and use.

(iii) Caution shall be exercised to maintain conductor and pair association both during and after splicing operations.

(iv) Splicing operations that involve pairs containing working services shall utilize splice connectors that permit splicing without the interruption of service.

(9) Piecing out conductors. Conductors may be pieced-out to provide additional slack or to repair damaged conductors. However, the conductors shall be pieced-out with conductors having the same gauge and type and color of insulation. The conductors used for piecing-out shall be from cables having RUS acceptance.

(10) Splice organization. Spliced pair bundles shall be arranged in firm lay-ups with minimum conductor tension in accordance with the manufacturer's instructions.

(11) Binder tape. Perforated nonhygroscopic and nonwicking binder tape should be applied to splices housed in filled splice cases. The binder tape allows the flow of filling compound while holding the splice bundles near the center of the splice case to allow adequate coverage of filling compound.

(12) Cable tags. Cables shall be identified by a tag indicating the cable manufacturer's name, cable size, date of placement, and generic route information. Information susceptible to changes caused by future cable throws and rearrangements should not be included. Tags on load coil stubs shall include the serial number of the coil case, the manufacturer's name, and the inductance value.

(13) Screened cable. Screened PIC cable is spliced in the same manner as nonscreened PIC cable. However, special considerations are necessary due to differences in the cable design. The transmit and receive bundles of the cable shall be separated and one of the bundles shall be wrapped with shielding material in accordance with the cable manufacturer's recommendations. When acceptable to the cable manufacturer, it is permissible to use either the scrap screening tape removed from the cable during the sheath opening process provided the screening tape is edge coated or new pressure sensitive aluminum foil tape over polyethylene tape.

(14) Service wire connections. (i) Buried service wires may be spliced directly to cable conductors inside pedestals using the same techniques required for branch cables. Buried service wires may also be terminated on terminal blocks inside pedestals in areas where high service order activity or fixed count cable administration policies require terminal blocks. However, only RUS accepted terminal blocks equipped with grease or gel filled terminations to provide moisture and corrosion resistance shall be used.

(ii) Only filled terminal blocks having RUS acceptance shall be used on aerial service wire connections.

(15) Copper cable testing. Copper cable testing shall be performed in accordance with RUS Bulletin 345-63, “RUS Standard for Acceptance Tests and Measurements of Telephone Plant,” PC-4, (Incorporated by reference at § 1755.97).

(16) Cable acceptance. Installed cable shall be tested and pass the inventory and acceptance testing specified in the Telephone System Construction Contract (Labor and Materials), RUS Form 515. The tests and inspections shall be witnessed by the borrower's resident project representative. All conductors shall be free from grounds, shorts, crosses, splits, and opens.

(d) Splice arrangements for copper cables—(1) Service distribution closures. (i) Ready access closures permit cable splicing activities and the installation of filled terminal blocks for service wire connections in the same closure. Ready access designs shall allow service technicians direct access to the cable core as well as the terminal block.

(ii) Fixed count terminals shall restrict service technician access to the cable core. Predetermined cable pairs shall be spliced to the terminal leads or stub cable in advance of service assignments.

(2) Aerial splices. Aerial splice cases accommodate straight splices, branch splices, load coils, and service distribution terminals. Aerial splicing arrangements having more than 4 cables spliced in the same splice case are not recommended. Stub cabling to a second splice case to avoid a congested splice is acceptable.

(3) Buried splices. (i) Direct buried splice cases accommodate straight splices, branch splices, and load coils. Direct buried splices shall be filled and shall be used only when above ground splicing in pedestals is not practicable.

(ii) A treated plank or equivalent shall be placed 15 cm (6 in.) above the buried splice case to prevent damage to the splice case from future digging. Where a firm base for burying a splice cannot be obtained, a treated plank or equivalent shall be placed beneath the splice case.

(iii) Each buried splice shall be identified for future locating. One method of marking the splice point is the use of a warning sign. Another method is the burying of an electronic locating device.

(4) BD-type pedestals. (i) BD-type pedestals are housings primarily intended to house, organize, and protect cable terminations incorporating splice connectors, ground lugs, and load coils. Activities typically performed in pedestals are cable splicing, shield bonding and grounding, loading, and connection of subscriber service drops.

(ii) The recommended splice capacities for BD-type pedestals are shown in Table 5. However, larger size pedestals are permissible if service requirements dictate their usefulness. Table 5 is as follows:

(iii) Special distribution pedestals having a divider plate for mounting filled terminal blocks are available. Distribution pedestals are also equipped with service wire channels for installation of buried service wires without disturbing the cabling and gravel inside the base of the pedestal. Distribution pedestals are recommended in locations where the connection of service wires is required.

(5) Large pair count splice housings. Large pair count splice housings are recommended for areas not suitable for man- holes. The recommended capacities are shown in Table 6:

(6) Pedestal restricted access inserts. Restricted access inserts may be used to protect splices susceptible to unnecessary handling where subsequent work activities are required or expected to occur after splices have been completed. Restricted access inserts also provide moisture protection in areas susceptible to temporary flooding. A typical restricted access insert is shown in Figure 1:

(7) Serving Area Interface (SAI) Systems. SAI systems provide the cross-connect point between feeder and distribution cables. Connection of feeder to distribution pairs is accomplished by placing jumpers between connecting blocks. Only RUS accepted connecting blocks having grease or gel filled terminations to provide moisture and corrosion resistance shall be used.

(8) Buried cable splicing arrangements. Typical buried cable splicing arrangements are illustrated in Figures 2 through 5:

(9) Underground splices (manholes). Underground splice cases accommodate straight splices, branch splices, and load coils. Underground splices shall be filled.

(10) Central office tip cable splices. (i) Filled cable or filled splices are not recommended for use inside central offices, except in cable vault locations. Outside plant cable sheath and cable filling compound are susceptible to fire and will support combustion. Fire, smoke, and gases generated by these materials during burning are detrimental to telephone switching equipment.

(ii) Tip cables should be spliced in a cable vault. However, as a last resort, tip cables may be spliced inside a central office if flame retardant splice cases or a noncombustible central office splice housing is used to contain the splice.

(iii) Splices inside the central office shall be made as close as practical to the point where the outside plant cables enter the building. Except in cable vault locations, outside plant cables within the central office shall be wrapped with fireproof tape or enclosed in noncombustible conduit.

(e) Splicing considerations for fiber optic cables—(1) Connection characteristics. Splicing efficiency between optical fibers is a function of light loss across the fiber junctions measured in decibels (dB). A loss of 0.2 dB in a splice corresponds to a light transmission efficiency of approximately 95.5 percent.

(2) Fiber core alignment. Fiber splicing techniques shall be conducted in such a manner that the cores of the fibers will be aligned as perfectly as possible to allow maximum light transmission from one fiber to the next. Without proper alignment, light will leave the fiber core and travel through the fiber cladding. Light outside the fiber core is not a usable light signal. Core misalignment is illustrated in Figure 6:

(3) Splice loss. (i) Splice loss can also be caused by fiber defects such as nonidentical core diameters, cores not in center of the fiber, and noncircular cores. Such defects are depicted in Figure 7:

(ii) Undesirable splice losses are caused by poor splicing techniques including splicing irregularities such as improper cleaves and dirty splices. Typical cleave problems are illustrated in Figure 8:

(4) Handling precautions. The following precautions shall be observed:

(i) Avoid damaging the cable during handling operations prior to splicing. Minor damage may change the transmission characteristics of the fibers to the extent that the cable section will have to be replaced;

(ii) The cable manufacturer's recommendations concerning pulling tension shall be observed. The maximum pulling tension for most fiber optic cable is 2669 newtons (600 pound-force);

(iii) The cable manufacturer's recommendations concerning bending radius shall be observed. Unless the cable manufacturer's recommendation is more stringent, the minimum bending radius for fiber optic cable shall be 20 times the cable diameter;

(iv) The cable manufacturer's recommendations concerning buffer tube bending radius shall be observed. Unless the cable manufacturer's recommendation is more stringent, the minimum bending radius for buffer tubes is usually between 38 millimeters (mm) (1.5 in.) and 76 mm (3.0 in.). The bending limitations on buffer tubes are intended to prevent kinking. Buffer tube kinking may cause excessive optical loss or fiber breakage; and

(v) Handle unprotected glass fibers carefully to avoid introducing flaws such as scratched or broken fibers.

(5) Personnel safety. The following safety precautions shall be observed:

(i) Safety glasses shall be worn when handling glass fibers;

(ii) Never view open-ended fibers with the naked eye or a magnifying device. Improper viewing of a fiber end that is transmitting light may cause irreparable eye damage; and

(iii) Dispose of bare scrap fibers by using the sticky side of a piece of tape to pick up and discard loose fiber ends. Fiber scraps easily penetrate the skin and are difficult to remove.

(6) Equipment requirements. (i) Fiber optic splices shall be made in areas where temperature, humidity, and cleanliness can be controlled. Both fusion and mechanical splicing techniques may require a splicing vehicle equipped with a work station that will allow environmental control.

(ii) Both fusion and mechanical splicing techniques are permitted on RUS financed projects. When using the mechanical splicing technique, only RUS accepted mechanical fiber optic splice connectors can be used.

(iii) Fusion splicing machines shall be kept in proper working condition. Regular maintenance in accordance with the machine manufacturer's recommendations shall be observed.

(iv) Mechanical splicing tools shall be in conformance with the tool manufacturer's recommendations.

(v) An optical time domain reflectometer (OTDR) shall be used for testing splices. The OTDR shall be stationed at the central office or launch point for testing individual splices as they are made and for end-to-end signature tests for the fiber optic link.

(vi) An optical power meter shall be used for end-to-end cable acceptance tests.

(vii) A prerequisite for the successful completion of a fiber optic splicing endeavor is the presence of a talk circuit between the splicing technician in the splicing vehicle and the operator of the OTDR in the central office. The splicing technician and the OTDR operator shall have access to communications with each other in order to inform each other as to:

(A) Which splices meet the loss objectives;

(B) The sequence in which buffer tubes and fibers are to be selected for subsequent splicing operations; and

(C) The timing required for the performance of OTDR testing to prevent making an OTDR test at the same time a splice is being fused.

(7) Cable preparation. (i) Engineering work prints shall prescribe the cable slack needed at splice points to reach the work station inside the splicing vehicle. Consideration should be given to the slack required for future maintenance activity as well as initial construction activities. The required slack may be different for each splice point, depending on the site logistics. However, the required slack is seldom less than 15 meters (50 feet). The amount of slack actually used shall be recorded for each splice point to assist future maintenance and restoration efforts.

(ii) The splice case manufacturer's recommendations concerning the amount of cable sheath to be removed shall be followed to facilitate splicing operations. The length of the sheath opening shall be identified with a wrap of plastic tape.

(iii) If the cable contains a rip cord, the cable jacket shall be ring cut approximately 15 cm (6 in.) from the end and the 15 cm (6 in.) of cable jacket shall be removed to expose the rip cord. The rip cord shall be used to slit the jacket to the tape mark.

(iv) If the cable does not contain a rip cord, the cable jacket shall be slit using a sheath splitter. No cuts shall be made into the cable core nor shall the buffer tubes be damaged.

(v) If the cable contains an armor sheath, the outer jacket shall be opened along the slit and the jacket shall be removed exposing the armor sheath. The armor shall be separated at the seam and pulled from the cable exposing the inner jacket. The armor shall be removed making allowances for a shield bond connector. The inner sheath shall be slit using a sheath splitter or rip cord. The cable core shall not be damaged nor shall there be any damage to the buffer tubes. The jacket shall be peeled back and cut at the end of the slit. The exposed buffer tubes shall not be cut, kinked, or bent.

(vi) After the cable sheath has been removed, the binder tape shall be removed from the cable. The cable shall not be crushed or deformed.

(vii) The buffer tubes shall be unstranded one at a time. The buffer tubes shall not be kinked.

(viii) If the cable is equipped with a strength member, the strength member shall be cut to the length recommended by the splice case manufacturer.

(ix) Each buffer tube shall be inspected for kinks, cuts, and flat spots. If damage is detected, an additional length of cable jacket shall be removed and all of the buffer tubes shall be cut off at the point of damage.

(x) The cable preparation sequence shall be repeated for the other cable end.

(8) Shield bonding and grounding. For personnel safety, the shields and metallic strength members of the cables to be spliced shall be bonded together and grounded before splicing activities are started. (See paragraphs (g)(4), and (g)(5)(i) through (g)(5)(iii) of this section for final bonding and grounding provisions).

(9) Fiber optic color code. The standard fiber optic color code for buffer tubes and individual fibers shall be as shown in Table 7:

(10) Buffer tube removal. (i) The splice case manufacturer's recommendation shall be followed concerning the total length of buffer tube to be removed. Identify the length to be removed with plastic tape.

(ii) Experiment with a scrap buffer tube to determine the cutting tool adjustment required to ring cut a buffer tube without damaging the fibers.

(iii) Buffer tubes shall be removed by carefully ring cutting and removing approximately 15 to 46 cm (6 to 18 in.) of buffer tube at a time. The process shall be repeated until the required length of buffer tube has been removed, including the tape identification marker.

(11) Coated fiber cleaning. (i) Each coated fiber shall be cleaned. The cable manufacturer's recommendations shall be followed concerning the solvent required to clean the coated fibers. Reagent grade isopropyl alcohol is a commonly used cleaning solvent.

(ii) A tissue or cotton ball shall be soaked in the recommended cleaning solvent and the coated fibers shall be carefully wiped one at a time using a clean tissue or cotton ball for each coated fiber. Caution shall be exercised to avoid removing the coloring agent from the fiber coating.

(12) Fiber coating removal. (i) Fiber coatings shall be removed. In accordance with the splicing method used, the splice case manufacturer's recommendation shall be followed concerning the length of fiber coating to be removed.

(ii) The recommended length of fiber coating shall be removed only on the two fibers to be spliced. Fiber coating removal shall be performed on a one-fiber-at-a-time basis as each splice is prepared.

(13) Bare fiber cleaning. After the fiber coating has been removed, the bare fibers shall be cleaned prior to splicing. Each fiber shall be wiped with a clean tissue or cotton ball soaked with the cleaning solvent recommended by the cable manufacturer. The bare fiber shall be wiped one time to minimize fiber damage. Aggressive wiping of bare fiber shall be avoided as it lowers the fiber tensile strength.

(14) Fiber cleaving. Cleaving tools shall be clean and have sharp cutting edges to minimize fiber scratches and improper cleave angles. Cleaving tools that are recommended by the manufacturer of the splicing system shall be used.

(15) Cleaved fiber handling. The cleaved and cleaned fiber shall not be allowed to touch other objects and shall be inserted into the splicing device.

(16) Completion of the splice. (i) In accordance with the method of splicing selected by the borrower, the splice shall be completed by either fusing the splice or by applying the mechanical connector.

(ii) Each spliced fiber shall be routed through the organizer tray one at a time as splices are completed. The fibers shall be organized one at a time to prevent tangled spliced fibers. The splice case manufacturer's recommendation shall be followed concerning the splice tray selection.

(17) Fiber optic testing. Fiber optic testing shall be performed in accordance with RUS Bulletin 345-63, “RUS Standard for Acceptance Tests and Measurements of Telephone Plant,” PC-4, (Incorporated by reference at § 1755.97).

(18) Cable acceptance. Installed cable shall be tested and pass the inventory and acceptance testing specified in the Telephone System Construction Contract (Labor and Materials), RUS Form 515. The tests and inspections shall be witnessed by the borrower's resident project representative.

(f) Splice arrangements for fiber optic cables—(1) Aerial splices. Cable slack at aerial splices shall be stored either on the messenger strand, on the pole, or inside a pedestal at the base of the pole. A typical arrangement for the storage of slack cable at aerial splices is shown in Figure 9:

(2) Buried splices. Buried splices shall be installed in handholes to accommodate the splice case and the required splicing slack. An alternative to the handhole is a pedestal specifically designed for fiber optic splice cases. Typical arrangements for buried cable splices are shown in Figures 10 and 11:

(3) Underground manhole splices. Underground splices shall be stored in manholes on cable hooks and racks fastened to the manhole wall. The cable slack shall be stored on cable hooks and racks as shown in Figure 12:

(4) Central office cable entrance. (i) Filled cable or filled splices are not recommended for use inside central offices except in cable vault locations. Outside plant cable sheath and cable filling compound are susceptible to fire and will support combustion. Fire, smoke, and gases generated by these materials during burning are detrimental to telephone switching equipment.

(ii) As a first choice, the outside plant fiber optic cable shall be spliced to an all-dielectric fire retardant cable in a cable vault with the all-dielectric cable extending into the central office and terminating inside a fiber patch panel.

(iii) As a second choice, the outside plant cable may be spliced inside the central office if a flame retardant fiber optic splice case or a noncombustible central office splice housing equipped with organizer trays is used to contain the splice.

(iv) In cases referenced in paragraphs (f)(4)(ii) and (f)(4)(iii) of this section, as a minimum the fire retardant all-dielectric cable used to provide the connection between the cable entrance splice and the fiber patch panel shall be listed as Communication Riser Cable (Type CMR) in accordance with Sections 800-50 and 800-51(b) of the 1993 National Electrical Code.

(v) Splices inside the central office shall be made as close as practicable to the point where the outside plant cables enter the building. Except in cable vault locations, outside plant cables within the central office shall be wrapped with fireproof tape or enclosed in noncombustible conduit.

(g) Bonding and grounding fiber optic cable, copper cable, and copper service wire—(1) Bonding. Bonding is electrically connecting two or more metallic items of telephone hardware to maintain a common electrical potential. Bonding may involve connections to another utility.

(2) Copper cable shield bond connections. (i) Cable shields shall be bonded at each splice location. Only RUS accepted cable shield bond connectors shall be used to provide bonding and grounding connections to metallic cable shields. The shield bond connector manufacturer's instructions shall be followed concerning installation and use.

(ii)(A) Shield bonding conductors shall be either stranded or braided tinned copper wire equivalent to a minimum No. 6 American Wire Gauge (AWG) and shall be RUS accepted. The conductor connections shall be tinned or of a compatible bimetallic design to avoid corrosion problems associated with dissimilar metals. The number of shield bond connectors required per pair size and gauge shall be as shown in Table 8:

(B) It is permissible to strap across the shield bond connectors of several cables with a single length of braided wire. However, both ends of the braid shall be terminated on the pedestal ground bracket to provide a bonding loop. Shield bond connection methods for individual cables are shown in Figures 13 through 15, and the bonding of several cables inside a pedestal using the bonding loop is shown in Figure 16:

(3) Buried service wire shield bond connections. Buried service wire shields shall be connected to the pedestal bonding and grounding system. Typical buried service wire installations are shown in Figures 17 and 18. In addition to the methods referenced in Figures 17 and 18, the shields of buried service wires may also be connected to the pedestal bonding and grounding system using buried service wire bonding harnesses listed on Page 3.3.1, Item “gs-b,” of RUS Bulletin 1755I-100. RUS Bulletin 1755I-100 may be purchased from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. When those harnesses are used they shall be installed in accordance with the manufacturer's instructions. Figures 17 and 18 are as follows:

(4) Fiber optic cable bond connections. (i) The cable shield and metallic strength members shall be bonded at each splice location. Only RUS accepted fiber optic cable shield bond connectors shall be used to provide bonding connections to the metallic cable shields. The shield bond connector manufacturer's instructions shall be followed concerning installation and use.

(ii) Shield bonding conductors shall be either stranded or braided tinned copper wire equivalent to a minimum No. 6 American Wire Gauge (AWG) and shall be RUS accepted. The conductor connections shall be tinned or of a compatible bimetallic design to avoid corrosion problems associated with dissimilar metals.

(5) Grounding. (i) Grounding is electrically connecting metallic telephone hardware to a National Electrical Safety Code (NESC) acceptable grounding electrode. Acceptable grounding electrodes are defined in the Rule 99A of the NESC.

(ii) The conductor used for grounding metallic telephone hardware shall be a minimum No. 6 AWG solid, bare, copper conductor.

(iii) For copper and fiber optic cable plant, all cable shields, all metallic strength members, and all metallic hardware shall be:

(A) Grounded at each splice location to a driven grounding electrode (ground rod) of:

(1) At least 1.5 meters (5 feet) in length where the local frost level is normally less than 0.30 meters (1 foot) deep; or

(2) At least 2.44 meters (8 feet) in length where the local frost level is normally 0.30 meters (1 foot) or deeper; and

(B) Bonded to a multi-grounded power system neutral when the splice is within 1.8 meters (6 feet) of access to the grounding system of the multi-grounded neutral system. Bonding to the multi-grounded neutral of a parallel power line may help to minimize telephone interference on long exposures with copper cable plant. Consideration, thus, should be given to completing such bonds, at least four (4) times each mile, when splices are greater than 1.8 meters (6 feet) but less than 4.6 meters (15 feet) from access to the multi-grounded neutral.

(6) Bonding and grounding splice cases. (i) Splice cases are equipped with bonding and grounding devices to ensure that cable shields and metallic strength members maintain electrical continuity during and after cable splicing operations. The splice case manufacturer's recommendations shall be followed concerning the bonding and grounding procedures. Conductors used for bonding shall be either stranded or braided tinned copper wire equivalent to 6 AWG. Conductors used for grounding shall be a solid, bare, copper wire equivalent to minimum No. 6 AWG.

(ii) Buried splice cases installed in either handholes or pedestals shall be grounded such that the cable shield grounds are attached to a common ground connection that will allow the lifting of a ground on the cable shield in either direction to permit efficient cable locating procedures. As a first choice, buried grounding conductor(s) shall be bare. However, if two or more grounding conductors are buried in the s they shall be insulated to avoid shorts when a locating tone is applied.

(iii) A typical bonding and grounding method for fiber optic splices is shown in Figure 19:

(7) Bonding and grounding central office cable entrances. The RUS Telecommunications Engineering and Construction Manual (TE&CM) Section 810 provides bonding and grounding guidance for central office cable entrances. Splicing operations shall not be attempted before all metallic cable shield and strength members are bonded and grounded.

[60 FR 5097, Jan. 26, 1995; 60 FR 9079, Feb. 16, 1995]

(a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990, for use on telecommunications systems financed by RUS loan funds must conform to this standard. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 on January 19, 1990). Copies of ASTM A475-78 are available for inspection during normal business hours at the National Archives and Records Administration (NARA) and the Rural Utilities Service, Administrative Services Division, room 0175-S, U.S. Department of Agriculture, Washington, DC 20250, telephone 202-382-9551. For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103, telephone 215-299-5400.

(b) In addition to the requirements of ASTM 475-78, all coils and reels having Class B or C coatings shall be marked with a 3-inch wide and 6-inch long deep-colored stripe, green or orange, respectively, to identify the class of galvanized coating of the strand. This marking shall be applied to the exposed convolutions of the strand in the eye of the coils and located near the midpoint on the outside layer of strand on the reels. The marking shall not cover any welded joint markings.

[55 FR 1792, Jan. 19, 1990; 55 FR 3685, Feb. 2, 1990. Redesignated at 55 FR 39397, Sept. 27, 1990, as amended at 69 FR 18803, Apr. 9, 2004]

(a) Scope. (1) This section covers the requirements for filled telephone cables intended for direct burial installation either by trenching or by direct plowing, for underground application by placement in a duct, or for aerial installations by attachment to a support strand.

(i) The conductors are solid copper, individually insulated with an extruded solid insulating compound.

(ii) The insulated conductors are twisted into pairs which are then stranded or oscillated to form a cylindrical core.

(iii) For high frequency applications, the cable core may be separated into compartments with screening shields.

(iv) A moisture resistant filling compound is applied to the stranded conductors completely covering the insulated conductors and filling the interstices between pairs and units.

(v) The cable structure is completed by the application of suitable core wrapping material, a flooding compound, a shield or a shield/armor, and an overall plastic jacket.

(2) The number of pairs and gauge size of conductors which are used within the RUS program are provided in the following table:

(3) Screened cable, when specified, must meet all requirements of this section. The pair sizes of screened cables used within the RUS program are referenced in paragraph (e)(2)(i) of this section.

(4) All cables sold to RUS borrowers for projects involving RUS loan funds under this section must be accepted by RUS Technical Standards Committee “A” (Telephone). For cables manufactured to the specification of this section, all design changes to an accepted design must be submitted for acceptance. RUS will be the sole authority on what constitutes a design change.

(5) Materials, manufacturing techniques, or cable designs not specifically addressed by this section may be allowed if accepted by RUS. Justification for acceptance of modified materials, manufacturing techniques, or cable designs must be provided to substantiate product utility and long-term stability and endurance.

(6) The American National Standard Institute/Insulated Cable Engineers Association, Inc. (ANSI/ICEA) S-84-608-1988 Standard For Telecommunications Cable, Filled, Polyolefin Insulated, Copper Conductor Technical Requirements referenced throughout this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies of ANSI/ICEA S-84-608-1988 are available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from ICEA, P. O. Box 440, South Yarmouth, MA 02664, telephone number (508) 394-4424.

(7) American Society for Testing and Materials specifications (ASTM) A 505-87, Standard Specification for Steel, Sheet and Strip, Alloy, Hot-Rolled and Cold-Rolled, General Requirements For; ASTM B 193-87, Standard Test Method for Resistivity of Electrical Conductor Materials; ASTM B 224-80, Standard Classification of Coppers; ASTM B 694-86, Standard Specification for Copper, Copper Alloy, and Copper-Clad Stainless Steel Sheet and Strip for Electrical Cable Shielding; ASTM D 4565-90a, Standard Test Methods for Physical and Environmental Performance Properties of Insulations and Jackets for Telecommunications Wire and Cable; and ASTM D 4566-90, Standard Test Methods for Electrical Performance Properties of Insulations and Jackets for Telecommunications Wire and Cable referenced in this section are incorporated by reference by RUS. These incorporations by references were approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies of the ASTM standards are available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from ASTM, 1916 Race Street, Philadelphia, PA 19103-1187, telephone number (215) 299-5585.

(b) Conductors and conductor insulation. (1) The gauge sizes of the copper conductors covered by this specification must be 19, 22, 24, and 26 American Wire Gauge (AWG).

(2) Each conductor must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 2.1.

(3) Factory joints made in conductors during the manufacturing process must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 2.2.

(4) The raw materials used for conductor insulation must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 3.1 through 3.1.3.

(5) The finished conductor insulation must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 3.2.1 and 3.3.

(6) Insulated conductors must not have an overall diameter greater than 2 millimeters (mm) (0.081 inch (in.)).

(7) A permissible overall performance level of faults in conductor insulation must average not greater than one fault per 12,000 conductor meters (40,000 conductor feet) for each gauge of conductor.

(i) All insulated conductors must be continuously tested for insulation faults during the twinning operation with a method of testing acceptable to RUS. The length count and number of faults must be recorded. The information must be retained for a period of 6 months and be available for review by RUS when requested.

(ii) The voltages for determining compliance with the requirements of this section are as follows:

(8) Repairs to the conductor insulation during manufacture are permissible. The method of repair must be accepted by RUS prior to its use. The repaired insulation must be capable of meeting the relevant electrical requirements of this section.

(9) All repaired sections of insulation must be retested in the same manner as originally tested for compliance with paragraph (b)(7) of this section.

(10) The colored insulating material removed from or tested on the conductor, from a finished cable, must meet the performance requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 3.4.1, 3.4.2, 3.4.4, 3.4.5, and 3.4.6.

(c) Identification of pairs and twisting of pairs. (1) The insulation must be colored to identify:

(i) The tip and ring conductor of each pair; and

(ii) Each pair in the completed cable.

(2) The colors to be used in the pairs in the 25 pair group, together with the pair numbers must be in accordance with the table specified in ANSI/ICEA S-84-608-1988, paragraph 3.5.

(3) Positive identification of the tip and ring conductors of each pair by marking each conductor of a pair with the color of its mate is permissible. The method of marking must be accepted by RUS prior to its use.

(4) Other methods of providing positive identification of the tip and ring conductors of each pair may be employed if accepted by RUS prior to its use.

(5) The insulated conductors must be twisted into pairs.

(6) In order to provide sufficiently high crosstalk isolation, the pair twists must be designed to enable the cable to meet the capacitance unbalance and crosstalk loss requirements of paragraphs (k)(5), (k)(6), and (k)(8) of this section.

(7) The average length of pair twists in any pair in the finished cable, when measured on any 3 meter (10 foot) length, must not exceed the requirement specified in ANSI/ICEA S-84-608-1988, paragraph 3.5.

(d) Forming of the cable core. (1) Twisted pairs must be assembled in such a way as to form a substantially cylindrical group.

(2) When desired for lay-up reasons, the basic group may be divided into two or more subgroups called units.

(3) Each group, or unit in a particular group, must be enclosed in bindings of the colors indicated for its particular pair count. The pair count, indicated by the colors of insulation, must be consecutive as indicated in paragraph (d)(6) of this section through units in a group.

(4) The filling compound must be applied to the cable core in such a way as to provide as near a completely filled core as is commercially practical.

(5) Threads and tapes used as binders must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 4.2 and 4.2.1.

(6) The colors of the bindings and their significance with respect to pair count must be as follows:

(7) The use of the white unit binder in cables of 100 pairs or less is optional.

(8) When desired for manufacturing reasons, two or more 25 pair groups may be bound together with nonhygroscopic and nonwicking threads or tapes into a super-unit. Threads or tapes must meet the requirements specified in paragraph (d)(5) of this section. The group binders and the super-unit binders must be color coded such that the combination of the two binders must positively identify each 25 pair group from every other 25 pair group in the cable. Super-unit binders must be of the color shown in the following table:

(9) Color binders must not be missing for more than 90 meters (300 feet) from any 25 pair group or from any subgroup used as part of a super-unit. At any cable cross-section, no adjacent 25 pair groups and no more than one subgroup of any super-unit may have missing binders. In no case must the total number of missing binders exceed three. Missing super-unit binders must not be permitted for any distance.

(10) Any reel of cable which contains missing binders must be labeled indicating the colors and location of the binders involved. The labeling must be applied to the reel and also to the cable.

(e) Screened cable. (1) Screened cable must be constructed such that a metallic, internal screen(s) must be provided to separate and provide sufficient isolation between the compartments to meet the requirements of this section.

(2) At the option of the user or manufacturer, identified service pairs providing for voice order and fault location may be placed in screened cables.

(i) The number of service pairs provided must be one per twenty-five operating pairs plus two for a cable size up to and including 400 pairs, subject to a minimum of four service pairs. The pair counts for screened cables are as follows:

(ii) The service pairs must be equally divided among the compartments. The color sequence must be repeated in each compartment.

(iii) The electrical and physical characteristics of each service pair must meet all the requirements set forth in this section.

(iv) The colors used for the service pairs must be in accordance with the requirements of paragraph (b)(5) of this section. The color code used for the service pairs together with the service pair number are shown in the following table:

(3) The screen tape must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 5.1 through 5.4.

(4) The screen tape must be tested for dielectric strength by completely removing the protective coating from one end to be used for grounding purposes.

(i) Using an electrode, over a 30 centimeter (1 foot) length, apply a direct current voltage at the rate of rise of 500 volts/second until failure.

(ii) No breakdown should occur below 8 kilovolts.

(f) Filling compound. (1) After or during the stranding operation and prior to application of the core wrap, filling compound must be applied to the cable core. The compound must be as nearly colorless as is commercially feasible and consistent with the end product requirements and pair identification.

(2) The filling compound must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 4.4 through 4.4.4.

(3) The individual cable manufacturer must satisfy RUS that the filling compound selected for use is suitable for its intended application. The filling compound must be applied to the cable in such a manner that the cable components will not be degraded.

(g) Core wrap. (1) The core wrap must comply with the requirements specified in ANSI/ICEA-S-84-608-1988, paragraph 4.3.

(2) If required for manufacturing reasons, white or colored binders of nonhygroscopic and nonwicking material may be applied over the core and/or wrap. When used, binders must meet the requirements specified in paragraph (d)(5) of this section.

(3) Sufficient filling compound must be applied to the core wrap so that voids or air spaces existing between the core and the inner side of the core wrap are minimized.

(h) Flooding compound. (1) Sufficient flooding compound must be applied on all sheath interfaces so that voids and air spaces in these areas are minimized. When the optional armored design is used, the flooding compound must be applied between the core wrap and shield, between the shield and armor, and between the armor and the jacket so that voids and air spaces in these areas are minimized. The use of floodant over the outer metallic substrate is not required if uniform bonding, per paragraph (i)(7) of this section, is achieved between the plastic-clad metal and the jacket.

(2) The flooding compound must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 4.5 and the jacket slip test requirements of appendix A, paragraph (III)(5) of this section.

(3) The individual cable manufacturer must satisfy RUS that the flooding compound selected for use is acceptable for the application.

(i) Shield and optional armor. (1) A single corrugated shield must be applied longitudinally over the core wrap.

(2) For unarmored cable the shield overlap must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.2. Core diameter is defined as the diameter under the core wrap and binding.

(3) For cables containing the coated aluminum shield/coated steel armor (CACSP) sheath design, the coated aluminum shield must be applied in accordance with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.2, Dual Tape Shielding System.

(4) General requirements for application of the shielding material are as follows:

(i) Successive lengths of shielding tapes may be joined during the manufacturing process by means of cold weld, electric weld, soldering with a nonacid flux, or other acceptable means.

(ii) Shield splices must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.3.

(iii) The corrugations and the application process of the coated aluminum and copper bearing shields must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.1.

(iv) The shielding material must be applied in such a manner as to enable the cable to pass the cold bend test specified in paragraph (l)(3) of this section.

(5) The following is a list of acceptable materials for use as cable shielding. Other types of shielding materials may also be used provided they are accepted by RUS prior to their use.

(i) The 8-mil aluminum tape must be plastic coated on both sides and must comply with the requirements of ANSI/ICEA S-84-608-1988, paragraph 6.2.2.

(ii) The 5-mil copper tape must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.2.3.

(iii) The 10-mil copper tape must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.2.4.

(iv) The 6-mil copper clad stainless steel tape must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.2.5.

(v) The 5-mil copper clad stainless steel tape must be in the fully annealed condition and must conform to the requirements of American Society for Testing and Materials (ASTM) B 694-86, with a cladding ratio of 16/68/16.

(A) The electrical conductivity of the clad tape must be a minimum of 28 percent of the International Annealed Copper Standard (IACS) when measured per ASTM B 193-87.

(B) The tape must be nominally 0.13 millimeter (0.005 inch) thick with a minimum thickness of 0.11 millimeter (0.0045 inch).

(vi) The 5-mil copper clad alloy steel tape must be in the fully annealed condition and the copper component must conform to the requirements of ASTM B 224-80 and the alloy steel component must conform to the requirements of ASTM A 505-87, with a cladding ratio of 16/68/16.

(A) The electrical conductivity of the copper clad alloy steel tape must comply with the requirement specified in paragraph (i)(5)(v)(A) of this section.

(B) The thickness of the copper clad alloy steel tape must comply with the requirements specified in paragraph (i)(5)(v)(B) of this section.

(vii) The 6-mil and 7-mil 194 copper alloy tapes must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.2.6.

(6) The corrugation extensibility of the coated aluminum shield must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.4.

(7) When the jacket is bonded to the plastic coated aluminum shield, the bond between the jacket and shield must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 7.2.6.

(8) A single plastic-coated steel corrugated armor must be applied longitudinally directly over the coated aluminum shield listed in paragraph (i)(5) of this section with an overlap complying with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.2, Outer Steel Tape.

(9) Successive lengths of steel armoring tapes may be joined during the manufacturing process by means of cold weld, electric weld, soldering with a nonacid flux, or other acceptable means. Armor splices must comply with the breaking strength and resistance requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.3.

(10) The corrugations and the application process of the coated steel armor must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.3.1.

(i) The corrugations of the armor tape must coincide with the corrugations of the coated aluminum shield.

(ii) Overlapped portions of the armor tape must be in register (corrugations must coincide at overlap) and in contact at the outer edge.

(11) The armoring material must be so applied to enable the cable to pass the cold bend test as specified in paragraph (l)(3) of this section.

(12) The 6-mil steel tape must be electrolytic chrome-coated steel (ECCS) plastic coated on both sides and must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 6.2.8.

(13) When the jacket is bonded to the plastic-coated steel armor, the bond between the jacket and armor must comply with the requirement specified in ANSI/ICEA-S-84-608-1988, paragraph 7.2.6.

(j) Cable jacket. (1) The jacket must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 7.2.

(2) The raw materials used for the cable jacket must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 7.2.1.

(3) Jacketing material removed from or tested on the cable must meet the performance requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 7.2.3 and 7.2.4.

(4) The thickness of the jacket must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 7.2.2.

(k) Electrical requirements—(1) Conductor resistance. The direct current resistance of any conductor in a completed cable and the average resistance of all conductors in a Quality Control Lot must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.1.

(2) Resistance unbalance. (i) The direct current resistance unbalance between the two conductors of any pair in a completed cable and the average resistance unbalance of all pairs in a completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.2.

(ii) The resistance unbalance between tip and ring conductors shall be random with respect to the direction of unbalance. That is, the resistance of the tip conductors shall not be consistently higher with respect to the ring conductors and vice versa.

(3) Mutual capacitance. The average mutual capacitance of all pairs in a completed cable and the individual mutual capacitance of any pair in a completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.3.

(4) Capacitance difference. (i) The capacitance difference for completed cables having 75 pairs or greater must comply with the requirement specified in ANSI/ICEA S-84-608-1988, paragraph 8.4.

(ii) When measuring screened cable, the inner and outer pairs must be selected from both sides of the screen.

(5) Pair-to-pair capacitance unbalance—(i) Pair-to-pair. The capacitance unbalance as measured on the completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.5.

(ii) Screened cable. In cables with 25 pairs or less and within each group of multigroup cables, the pair-to-pair capacitance unbalance between any two pairs in an individual compartment must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.5. The pair-to-pair capacitance unbalances to be considered must be:

(A) Between pairs adjacent in a layer in an individual compartment;

(B) Between pairs in centers of 4 pairs or less in an individual compartment; and

(C) Between pairs in adjacent layers in an individual compartment when the number of pairs in the inner (smaller) layer is 6 or less. The center is counted as a layer.

(iii) In cables with 25 pairs or less, the root-mean-square (rms) value must include all the pair-to-pair unbalances measured for each compartment separately.

(iv) In cables containing more than 25 pairs, the rms value must include the pair-to-pair unbalances in the separate compartments.

(6) Pair-to-ground capacitance unbalance—(i) Pair-to-ground. The capacitance unbalance as measured on the completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.6.

(ii) When measuring pair-to-ground capacitance unbalance all pairs except the pair under test are grounded to the shield and/or shield/armor except when measuring cables containing super units in which case all other pairs in the same super unit must be grounded to the shield.

(iii) The screen tape must be left floating during the test.

(iv) Pair-to-ground capacitance unbalance may vary directly with the length of the cable.

(7) Attenuation. (i) For nonscreened and screened cables, the average attenuation of all pairs on any reel when measured at 150 and 772 kilohertz must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.7, Solid Column.

(ii) For T1C type cables over 12 pairs, the maximum average attenuation of all pairs on any reel must not exceed the values listed below when measured at a frequency of 1576 kilohertz at or corrected to a temperature of 20 ±1 °C. The test must be conducted in accordance with ASTM D 4566-90.

(8) Crosstalk loss. (i) The equal level far-end power sum crosstalk loss (FEXT) as measured on the completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.8, FEXT Table.

(ii) The near-end power sum crosstalk loss (NEXT) as measured on completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.8, NEXT Table.

(iii) Screened cable. (A) For screened cables the NEXT as measured on the completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 8.9 and 8.9.1.

(B) For T1C screened cable the NEXT as measured on the completed cable must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraphs 8.9 and 8.9.2.

(9) Insulation resistance. The insulation resistance of each insulated conductor in a completed cable must comply with the requirement specified in ANSI/ICEA S-84-608-1988, paragraph 8.11.

(10) High voltage test. (i) In each length of completed cable, the insulation between conductors must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.12, Solid Column.

(ii) In each length of completed cable, the dielectric between the shield and/or armor and conductors in the core must comply with the requirements specified in ANSI/ICEA S-84-608-1988, paragraph 8.13, Single Jacketed, Solid Column. In screened cable the screen tape must be left floating.

(iii) Screened cable. (A) In each length of completed screened cable, the dielectric between the screen tape and the conductors in the core must comply with the requirement specified in ANSI/ICEA S-84-608-1988, paragraph 8.14.

(B) In this test, the cable shield and/or armor must be left floating.

(11) Electrical variations. (i) Pairs in each length of cable having either a ground, cross, short, or open circuit condition will not be permitted.

(ii) The maximum number of pairs in a cable which may vary as specified in paragraph (k)(11)(iii) of this section from the electrical parameters given in this section are listed below. These pairs may be excluded from the arithmetic calculation.

(iii) Parameter variations. (A) Capacitance unbalance-to-ground. If the cable fails either the maximum individual pair or average capacitance unbalance-to-ground requirement and all individual pairs are 3937 picofarad/kilometer (1200 picofarad/1000 feet) or less, the number of pairs specified in paragraph (k)(11)(ii) of this section may be eliminated from the average and maximum individual calculations.

(B) Resistance unbalance. Individual pair of 7 percent for all gauges.

(C) Conductor resistance, maximum. The following table shows maximum conductor resistance:

(l) Mechanical requirements—(1) Compound flow test. All cables manufactured in accordance with the requirements of this section must be capable of meeting the compound flow test specified in ANSI/ICEA S-84-608-1988, paragraph 9.1 using a test temperature of 80 ±1 °C.

(2) Water penetration. All cables manufactured in accordance with the requirements of this section must be capable of meeting the water penetration test specified in ANSI/ICEA S-84-608-1988, paragraph 9.2.

(3) Cable cold bend test. All cables manufactured in accordance with the requirements of this section must be capable of meeting the cable cold bend test specified in ANSI/ICEA S-84-608-1988, paragraph 9.3.

(4) Cable impact test. All cables manufactured in accordance with the requirements of this section must be capable of meeting the cable impact test specified in ANSI/ICEA S-84-608-1988, paragraph 9.4.

(5) Jacket notch test (CACSP sheath only). All cables utilizing the coated aluminum/coated steel sheath (CACSP) design manufactured in accordance with the requirements of this section must be capable of meeting the jacket notch test specified in ANSI/ICEA S-84-608-1988, paragraph 9.5.

(6) Cable torsion test (CACSP sheath only). All cables utilizing the coated aluminum/coated steel sheath (CACSP) design manufactured in accordance with the requirements of this section must be capable of meeting the cable torsion test specified in ANSI/ICEA S-84-608-1988, paragraph 9.6.

(m) Sheath slitting cord (optional). (1) Sheath slitting cords may be used in the cable structure at the option of the manufacturer unless specified by the end user.

(2) When a sheath slitting cord is used it must be nonhygroscopic and nonwicking, continuous throughout a length of cable and of sufficient strength to open the sheath without breaking the cord.

(n) Identification marker and length marker. (1) Each length of cable must be identified in accordance with ANSI/ICEA S-84-608-1988, paragraphs 10.1 through 10.1.4. The color of the ink used for the initial outer jacket marking must be either white or silver.

(2) The markings must be printed on the jacket at regular intervals of not more than 0.6 meter (2 feet).

(3) The completed cable must have sequentially numbered length markers in accordance with ANSI/ICEA S-84-608-1988, paragraph 10.1.5. The color of the ink used for the initial outer jacket marking must be either white or silver.

(o) Preconnectorized cable (optional). (1) At the option of the manufacturer and upon request by the purchaser, cables 100 pairs and larger may be factory terminated in 25 pair splicing modules.

(2) The splicing modules must meet the requirements of RUS Bulletin 345-54, PE-52, RUS Specification for Telephone Cable Splicing Connectors (Incorporated by reference at § 1755.97), and be accepted by RUS prior to their use.

(p) Acceptance testing and extent of testing. (1) The tests described in appendix A of this section are intended for acceptance of cable designs and major modifications of accepted designs. What constitutes a major modification is at the discretion of RUS. These tests are intended to show the inherent capability of the manufacturer to produce cable products having long life and stability.

(2) For initial acceptance, the manufacturer must submit:

(i) An original signature certification that the product fully complies with each section of the specification;

(ii) Qualification Test Data, per appendix A of this section;

(iii) To periodic plant inspections;

(iv) A certification that the product does or does not comply with the domestic origin manufacturing provisions of the “Buy American” requirements of the Rural Electrification Act of 1938 (7 U.S.C. 901 et seq.);

(v) Written user testimonials concerning field performance of the product; and

(vi) Other nonproprietary data deemed necessary by the Chief, Outside Plant Branch (Telephone).

(3) For requalification acceptance, the manufacturer must submit an original signature certification that the product fully complies with each section of the specification, excluding the Qualification Section, and a certification that the product does or does not comply with the domestic origin manufacturing provisions of the “Buy American” requirements of the Rural Electrification Act of 1938 (7 U.S.C. 901 et seq.), for acceptance by August 30 of each year. The required data must have been gathered within 90 days of the submission. If the initial acceptance of a product to this specification was within 180 days of August 30, then requalification for that product will not be required for that year.

(4) Initial and requalification acceptance requests should be addressed to:

Chairman, Technical Standards Committee “A” (Telephone), Telecommunications Standards Division, Rural Utilities Service, Washington, DC 20250-1500.

(5) Tests on 100 percent of completed cable. (i) The shield and/or armor of each length of cable must be tested for continuity in accordance with ANSI/ICEA S-84-608-1988, paragraph 8.16.

(ii) The screen tape of each length of screened cable must be tested for continuity in accordance with ANSI/ICEA S-84-608-1988, paragraph 8.16.

(iii) Dielectric strength between conductors and shield and/or armor must be tested to determine freedom from grounds in accordance with paragraph (k)(10)(ii) of this section.

(iv) Dielectric strength between conductors and screen tape must be tested to determine freedom from grounds in accordance with paragraph (k)(10)(iii) of this section.

(v) Each conductor in the completed cable must be tested for continuity in accordance with ANSI/ICEA S-84-608-1988, paragraph 8.16.

(vi) Dielectric strength between conductors must be tested to insure freedom from shorts and crosses in each length of completed cable in accordance with paragraph (k)(10)(i) of this section.

(vii) Each conductor in the completed preconnectorized cable must be tested for continuity.

(viii) Each length of completed preconnectorized cable must be tested for split pairs.

(ix) The average mutual capacitance must be measured on all cables. If the average mutual capacitance for the first 100 pairs tested from randomly selected groups is between 50 and 53 nanofarad/kilometer (nF/km) (80 and 85 nanofarad/mile), the remainder of the pairs need not be tested on the 100 percent basis (See paragraph (k)(3) of this section).

(6) Capability tests. Tests on a quality assurance basis must be made as frequently as is required for each manufacturer to determine and maintain compliance with:

(i) Performance requirements for conductor insulation, jacketing material, and filling and flooding compounds;

(ii) Bonding properties of coated or laminated shielding and armoring materials and performance requirements for screen tape;

(iii) Sequential marking and lettering;

(iv) Capacitance difference, capacitance unbalance, crosstalk, and attenuation;

(v) Insulation resistance, conductor resistance and resistance unbalance;

(vi) Cable cold bend and cable impact tests;

(vii) Water penetration and compound flow tests; and

(viii) Jacket notch and cable torsion tests.

(q) Summary of records of electrical and physical tests. (1) Each manufacturer must maintain suitable summary records for a period of at least 3 years of all electrical and physical tests required on completed cable by this section as set forth in paragraphs (p)(5) and (p)(6) of this section. The test data for a particular reel must be in a form that it may be readily available to the purchaser or to RUS upon request.

(2) Measurements and computed values must be rounded off to the number of places or figures specified for the requirement according to ANSI/ICEA S-84-608-1988, paragraph 1.3.

(r) Manufacturing irregularities. (1) Repairs to the shield and/or armor are not permitted in cable supplied to end users under this section.

(2) Minor defects in jackets (defects having a dimension of 3 millimeters (0.125 inch) or less in any direction) may be repaired by means of heat fusing in accordance with good commercial practices utilizing sheath grade compounds.

(s) Preparation for shipment. (1) The cable must be shipped on reels. The diameter of the drum must be large enough to prevent damage to the cable from reeling or unreeling. The reels must be substantial and so constructed as to prevent damage to the cable during shipment and handling.

(2) The thermal wrap must comply with the requirements of ANSI/ICEA S-84-608-1988, paragraph 10.3. When a thermal reel wrap is supplied, the wrap must be applied to the reel and must be suitably secured in place to minimize thermal exposure to the cable during storage and shipment. The use of the thermal reel wrap as a means of reel protection will be at the option of the manufacturer unless specified by the end user.

(3) The outer end of the cable must be securely fastened to the reel head so as to prevent the cable from becoming loose in transit. The inner end of the cable must be securely fastened in such a way as to make it readily available if required for electrical testing. Spikes, staples, or other fastening devices which penetrate the cable jacket must not be used. The method of fastening the cable ends must be accepted by RUS prior to its use.

(4) Each length of cable must be wound on a separate reel unless otherwise specified or agreed to by the purchaser.

(5) The arbor hole must admit a spindle 63 millimeters (2.5 inches) in diameter without binding. Steel arbor hole liners may be used but must be accepted by RUS prior to their use.

(6) Each reel must be plainly marked to indicate the direction in which it should be rolled to prevent loosening of the cable on the reel.

(7) Each reel must be stenciled or labeled on either one or both sides with the information specified in ANSI/ICEA S-84-608-1988, paragraph 10.4 and the RUS cable designation:

Cable Designation BFC Cable Construction Pair Count Conductor Gauge A = Coated Aluminum Shield C = Copper Shield Y = Gopher Resistant Shield X = Armored, Separate Shield H = T1 Screened Cable H1C = T1C Screened Cable P = Preconnectorized Example: BFCXH100-22 Buried Filled Cable, Armored (w/separate shield), T1 Screened Cable, 100 pair, 22 AWG.

(8) When cable manufactured to the requirements of this section is shipped, both ends must be equipped with end caps acceptable to RUS.

(9) When preconnectorized cables are shipped, the splicing modules must be protected to prevent damage during shipment and handling. The protection method must be acceptable to RUS and accepted prior to its use.

(10) All cables ordered for use in underground duct applications must be equipped with a factory-installed pulling-eye on the outer end in accordance with ANSI/ICEA S-84-608-1988, paragraph 10.5.2.

(The information and recordkeeping requirements of this section have been approved by the Office of Management and Budget under the control number 0572-0059) Appendix A to § 1755.390—Qualification Test Methods

(I) The test procedures described in this appendix are for qualification of initial designs and major modification of accepted designs. Included in (V) of this appendix are suggested formats that may be used in submitting the test results to RUS.

(II) Sample selection and preparation. (1) All testing must be performed on lengths removed sequentially from the same 25 pair, 22 gauge jacketed cable. This cable must not have been exposed to temperatures in excess of 38 °C since its initial cool down after sheathing. The lengths specified are minimum lengths and if desirable from a laboratory testing standpoint longer lengths may be used.

(a) Length A shall be 10 ±0.2 meters (33 ±0.5 feet) long and must be maintained at 23 ±3 °C. One length is required.

(b) Length B shall be 12 ±0.2 meters (40 ±0.5 feet) long. Prepare the test sample by removing the jacket, shield or shield/armor and core wrap for a sufficient distance on both ends to allow the insulated conductors to be flared out. Remove sufficient conductor insulation so that appropriate electrical test connections can be made at both ends. Coil the sample with a diameter of 15 to 20 times its sheath diameter. Three lengths are required.

(c) Length C shall be one meter (3 feet) long. Four lengths are required.

(d) Length D shall be 300 millimeters (1 foot) long. Four lengths are required.

(e) Length E must be 600 millimeters (2 feet) long. Four lengths are required.

(f) Length F shall be 3 meters (10 feet) long and must be maintained at 23 ±3 °C for the duration of the test. Two lengths are required.

(2) Data reference temperature. Unless otherwise specified, all measurements must be made at 23 ±3 °C.

(III) Environmental tests—(1) Heat aging test—(a) Test samples. Place one sample each of lengths B, C, D and E in an oven or environmental chamber. The ends of Sample B must exit from the chamber or oven for electrical tests. Securely seal the oven exit holes.

(b) Sequence of tests. The samples are to be subjected to the following tests after conditioning:

(i) Water Immersion Test outlined in (III)(2) of this appendix;

(ii) Water Penetration Test outlined in (III)(3) of this appendix;

(iii) Insulation Compression Test outlined in (III)(4) of this appendix; and

(iv) Jacket Slip Strength Test outlined in (III)(5) of this appendix.

(c) Initial measurements. (i) For Sample B measure the open circuit capacitance for each odd numbered pair at 1, 150, and 772 kilohertz, and the attenuation at 150 and 772 kilohertz after conditioning the sample at the data reference temperature for 24 hours. Calculate the average and standard deviation for the data of the 13 pairs on a per kilometer or (on a per mile) basis.

(ii) The attenuation at 150 and 772 kilohertz may be calculated from open circuit admittance (Yoc) and short circuit impedance (Zsc) or may be obtained by direct measurement of attenuation.

(iii) Record on suggested formats in (V) of this appendix or on other easily readable formats.

(d) Heat conditioning. (i) Immediately after completing the initial measurements, condition the sample for 14 days at a temperature of 65 ±2 °C.

(ii) At the end of this period note any exudation of cable filler. Measure and calculate the parameters given in (III)(1)(c) of this appendix. Record on suggested formats in (V) of this appendix or on other easily readable formats.

(iii) Cut away and discard a one meter (3 foot) section from each end of length B.

(e) Overall electrical deviation. (i) Calculate the percent change in all average parameters between the final parameters after conditioning and the initial parameters in (III)(1)(c) of this appendix.

(ii) The stability of the electrical parameters after completion of this test must be within the following prescribed limits:

(A) Capacitance. The average mutual capacitance must be within 5 percent of its original value;

(B) The change in average mutual capacitance must be less than 5 percent over frequency 1 to 150 kilohertz; and

(C) Attenuation. The 150 and 772 kilohertz attenuation must not have increased by more than 5 percent over their original values.

(2) Water immersion electrical test—(a) Test sample selection. The 10 meter (33 foot) section of length B must be tested.

(b) Test sample preparation. Prepare the sample by removing the jacket, shield or shield/armor, and core wrap for sufficient distance to allow one end to be accessed for test connections. Cut out a series of 6 millimeter (0.25 inch) diameter holes along the test sample, at 30 centimeters (1 foot) intervals progressing successively 90 degrees around the circumference of the cable. Assure that the cable core is exposed at each hole by slitting the core wrapper. Place the prepared sample in a dry vessel which when filled will maintain a one meter (3 foot) head of water over 6 meters (20 feet) of uncoiled cable. Extend and fasten the ends of the cable so they will be above the water line and the pairs are rigidly held for the duration of the test.

(c) Capacitance testing. Measure the initial values of mutual capacitance of all odd pairs in each cable at a frequency of 1 kilohertz before filling the vessel with water. Be sure the cable shield or shield/armor is grounded to the test equipment. Fill the vessels until there is a one meter (3 foot) head of water on the cables.

(i) Remeasure the mutual capacitance after the cables have been submerged for 24 hours and again after 30 days.

(ii) Record each sample separately on suggested formats in (V) of this appendix or on other easily readable formats.

(d) Overall electrical deviation. (i) Calculate the percent change in all average parameters between the final parameters after conditioning with the initial parameters in (III)(2)(c) of this appendix.

(ii) The average mutual capacitance must be within 5 percent of its original value.

(3) Water penetration testing. (a) A watertight closure must be placed over the jacket of length C. The closure must not be placed over the jacket so tightly that the flow of water through pre-existing voids of air spaces is restricted. The other end of the sample must remain open.

(b) Test per Option A or Option B—(i) Option A. Weigh the sample and closure prior to testing. Fill the closure with water and place under a continuous pressure of 10 ±0.7 kilopascals (1.5 ±0.1 pounds per square inch gauge) for one hour. Collect the water leakage from the end of the test sample during the test and weigh to the nearest 0.1 gram. Immediately after the one hour test, seal the ends of the cable with a thin layer of grease and remove all visible water from the closure, being careful not to remove water that penetrated into the core during the test. Reweigh the sample and determine the weight of water that penetrated into the core. The weight of water that penetrated into the core must not exceed 8 grams.

(ii) Option B. Fill the closure with a 0.2 gram sodium fluorscein per liter water solution and apply a continuous pressure 10 ±0.7 kilopascals (1.5 ±0.1 pounds per square inch gauge) for one hour. Catch and weigh any water that leaks from the end of the cable during the one hour period. If no water leaks from the sample, carefully remove the water from the closure. Then carefully remove the jacket, shield or shield/armor and core wrap one at a time, examining with an ultraviolet light source for water penetration. After removal of the core wrap, carefully dissect the core and examine for water penetration within the core. Where water penetration is observed, measure the penetration distance. The distance of water penetration into the core must not exceed 127 millimeters (5.0 inches).

(4) Insulation compression test—(a) Test Sample D. Remove jacket, shield or shield/armor, and core wrap being careful not to damage the conductor insulation. Remove one pair from the core and carefully separate, wipe off core filler, and straighten the insulated conductors. Retwist the two insulated conductors together under sufficient tension to form 10 evenly spaced 360 degree twists in a length of 10 centimeters (4 inches).

(b) Sample testing. Center the mid 50 millimeters (2 inches) of the twisted pair between 2 smooth rigid parallel metal plates that are 50 millimeters × 50 millimeters (2 inches × 2 inches). Apply a 1.5 volt direct current potential between the conductors, using a light or buzzer to indicate electrical contact between the conductors. Apply a constant load of 67 newtons (l5 pound-force) on the sample for one minute and monitor for evidence of contact between the conductors. Record results on suggested formats in (V) of this appendix or on other easily readable formats.

(5) Jacket slip strength test—(a) Sample selection. Test Sample E from (III)(1)(a) of this appendix.

(b) Sample preparation. Prepare test sample in accordance with the procedures specified in ASTM D 4565-90a.

(c) Sample conditioning and testing. Remove the sample from the tensile tester prior to testing and condition for one hour at 50 ±2 °C. Test immediately in accordance with the procedures specified in ASTM D 4565-90a. A minimum jacket slip strength of 67 newtons (15 pound-force) is required. Record the highest load attained.

(6) Humidity exposure. (a) Repeat steps (III)(1)(a) through (III)(1)(c)(iii) of this appendix for separate set of samples B, C, D, and E which have not been subjected to prior environmental conditioning.

(b) Immediately after completing the measurements, expose the test sample to 100 temperature cyclings. Relative humidity within the chamber must be maintained at 90 ±2 percent. One cycle consists of beginning at a stabilized chamber and test sample temperature of 52 ±1 °C, increasing the temperature to 57 ±1 °C, allowing the chamber and test samples to stabilize at this level, then dropping the temperature back to 52 ±1 °C.

(c) Repeat steps (III)(1)(d)(ii) through (III)(5)(c) of this appendix.

(7) Temperature cycling. (a) Repeat steps (III)(1)(a) through (III)(1)(c)(iii) of this appendix for separate set of samples B, C, D, and E which have not been subjected to prior environmental conditioning.

(b) Immediately after completing the measurements, subject the test sample to the 10 cycles of temperature between a minimum of −40 °C and + 60 °C. The test sample must be held at each temperature extreme for a minimum of 1 1/2 hours during each cycle of temperature. The air within the temperature cycling chamber must be circulated throughout the duration of the cycling.

(c) Repeat steps (III)(1)(d)(ii) through (III)(5)(c) of this appendix.

(IV) Control sample—(1) Test samples. A separate set of lengths A, C, D, E, and F must have been maintained at 23 ±3 °C for at least 48 hours before the testing.

(2) Repeat steps (III)(2) through (III)(5)(c) of this appendix except use length A instead of length B.

(3) Surge Test. (a) One length of sample F must be used to measure the breakdown between conductors while the other length of F must be used to measure the core to shield breakdown.

(b) The samples must be capable of withstanding without damage, a single surge voltage of 20 kilovolts peak between conductors, and a 35 kilovolts peak surge voltage between conductors and the shield or shield/armor as hereinafter described. The surge voltage must be developed from a capacitor discharged through a forming resistor connected in parallel with the dielectric of the test sample. The surge generator constants must be such as to produce a surge of 1.5 × 40 microsecond wave shape.

(c) The shape of the generated wave must be determined at a reduced voltage by connecting an oscilloscope across the forming resistor with the cable sample connected in parallel with the forming resistor. The capacitor bank is charged to the test voltage and then discharged through the forming resistor and test sample. The test sample will be considered to have passed the test if there is no distinct change in the wave shape obtained with the initial reduced voltage compared to that obtained after the application of the test voltage.

(V) The following suggested formats may be used in submitting the test results to RUS:

[58 span 29338, May 20, 1993; 58 span 32749, June 11, 1993, as amended at 60 span 1711, Jan. 5, 1995; 69 span 18803, Apr. 9, 2004]

(a) General. (1) This section covers general requirements for a line concentrator (LC) system. This system shall operate in accordance with the manufacturer's specifications. Reliability shall be of prime importance in the design, manufacture and installation of the equipment. The equipment shall automatically provide for:

(i) Terminating subscriber lines at a location remote from the serving central office;

(ii) Concentrating the subscriber lines over a few transmission and supervisory paths to the serving central office; and

(iii) Terminating the lines at the central office without loss of individual identity. A subscriber connected to a line concentrator shall be capable of having essentially the same services as a subscriber connected directly to the central office equipment (COE). Intra-unit calling among subscribers connected to the concentrator may be provided, but is not required.

(2) Industry standards, or portions thereof, referred to in this paragraph (a) are incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552 (a) and 1 CFR part 51. Copies of these standards are available for inspection during normal business hours at RUS, room 2838, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(3) American National Standards Institute (ANSI) standards are available from ANSI Inc., 11 West 42nd Street, 13th floor, New York, NY 10036, telephone 212-642-4900.

(i) ANSI Standard S1.4-1983, Specification for Sound Level Meters, including Amendment S1.4A-1985.

(ii) [Reserved]

(4) American Society for Testing Materials (ASTM) are available from 1916 Race Street, Philadelphia, PA 19103, telephone 215-299-5400.

(i) ASTM Specification B33-91, Standard Specifications for Tinned Soft or Annealed Copper Wire for Electrical Purposes.

(ii) [Reserved]

(5) Bell Communications Research (Bellcore) standards are available from Bellcore Customer Service, 8 Corporate Place, Piscataway, NJ 08854, telephone 1-800-521-2673.

(i) span-TSY-000008, Issue 2, August 1987, Digital Interface between the SLC 96 Digital Loop Carrier System and a Local Digital Switch.

(ii) Bell Communications Research (Bellcore) document span-TSY-000057, Issue 1, April 1987, including Revision 1, November 1988, Functional Criteria for Digital Loop Carrier Systems.

(iii) Bell Communications Research (Bellcore) Document span-NWT-000303, Issue 2, December 1992, including Revision 1, December 1993, Integrated Digital Loop Carrier System Generic Requirements, Objectives, and Interface.

(6) Federal Standard H28, Screw-Thread Standards for Federal Services, March 31, 1978, including Change Notice 1, May 28, 1986; Change Notice 2, January 20, 1989; and Change Notice 3, March 12, 1990. Copies may be obtained from the General Services Administration, Specification Section, 490 East L'Enfant Plaza SW, Washington, DC 20407, telephone 202-755-0325.

(7) IEEE standards are available from IEEE Service Center, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08854, telephone 1-800-521-2673.

(i) IEEE Standard 455-1985, Standard Test Procedure for Measuring Longitudinal Balance of Telephone Equipment Operating in the Voice Band.

(ii) [Reserved]

(8) RUS standards are available from Publications and Directives Management Branch, Administrative Services Division, Rural Utilities Service, room 0180, South Building, U.S. Department of Agriculture, Washington, DC 20250-1500.

(i) RUS Bulletin 345-50, PE-60 (Sept 1979), RUS Specification for Trunk Carrier Systems.

(ii) [Reserved]

(b) Types of requirements. (1) Unless otherwise indicated, the requirements listed in this section are considered to be fixed requirements.

(2) The concentrator system shall communicate with standard T1 digital transmission format at a minimum between the concentrator and central office terminals. Analog conversion functions at remote and central office terminals shall be capable of being eliminated to accommodate end-to-end digital transmission.

(3) The LC shall operate properly as an integral part of the telephone network when connected to physical or carrier derived circuits and central offices meeting RUS specifications and other generally accepted telecommunications practices, such as Bellcore documents span-NWT-000303, Integrated Digital Loop Carrier System Generic Requirements, Objectives and Interface; span-TSY-000008, Digital Interface between the SLC 96 Digital Loop Carrier System and a Local Digital Switch; and span-TSY-000057, Functional Criteria for Digital Loop Carrier Systems.

(4) For RUS acceptance consideration of a LC, the manufacturer must certify and demonstrate that all requirements specified in this section are available and in compliance with this section.

(5) Certain requirements are included in this section for features which may not be needed for every application. Such features are identifiable by the inclusion in the requirements of some such phrase as “when specified by the owner” or “as specified by the owner.” In some cases where an optional feature will not be required by an owner, either now or in the future, a system which does not provide this feature shall be considered to be in compliance with the specification for the specific installation under consideration, but not in compliance with the entire specification.

(6) The owner may properly request bids from any supplier of an RUS accepted LC whose system provides all the features which will be required for a specific installation.

(7) When required by the owner, the supplier shall state compliance to the Carrier Serving Area (CSA) requirements, as stated in Bell Communications Research (Bellcore) Standard span-TSY-000057, Functional Criteria for Digital Loop Carrier Systems.

(c) Reliability. (1) The failure rate of printed circuit boards shall not exceed an average of 2.0 percent per month of all equipped cards in all system terminals during the first 3 months after cutover, and shall not exceed an average of 1.0 percent per month of all equipped cards in all system terminals during the second 3-month period. The failure rate for the equipment shall be less than 0.5 percent per month of all equipped cards in all system terminals after 6 months. A failure is considered to be the failure of a component on the PC board which requires it to be repaired or replaced.

(2) The line concentrator terminal units shall be designed such that there will be no more than 4 hours of total outages in 20 years.

(d) System type acceptance tests. General test results will be required on each system type. Any system provided in accordance with this section shall be capable of meeting any requirement in this section on a spot-check basis.

(e) Features required. The network control equipment and peripheral equipment shall be comprised of solid-state and integrated circuitry components as far as practical and in keeping with the state-of-the-art and economics of the subject system.

(f) Subscriber lines—(1) General. (i) The remote LC units shall operate satisfactorily with subscriber lines which meet all of the conditions under the bidder's specifications and all the requirements of this section. This section recognizes that the loop limit of the line concentrator is dependent upon the transmission facility between the LC central office termination and the LC remote unit. When voice frequency (physical) circuits are used, the loop limit from the COE to the subscriber shall be 1900 ohms (including the telephone set). When electronically derived circuits (carrier, lightwave, etc.) are used, the loop limits of the electronic system will control. The bidder shall identify the loop limits of the equipment to be supplied.

(ii) There should be provisions for such types of lines as ground start, loop start, regular subscriber, pay stations, etc.

(2) Dialing. (i) General. The line concentrator remote and central office terminal equipment shall satisfactorily transmit dialing information when used with subscriber dials having a speed of operation between 8 and 12 dial pulses per second and a break period of 55 to 65% of the total signaling period.

(ii) Subscriber dial interdigital time. The remote and central office LC equipment shall permit satisfactory telecommunications operation when used with subscriber rotary dial interdigital times of 200 milliseconds minimum, and pushbutton dialing with 50 milliseconds minimum.

(iii) Subscriber line pushbutton dialing frequencies. The frequency pairs assigned for pushbutton dialing when provided by the central office shall be as listed in this paragraph (f)(2)(iii), with an allowable variation of ±1.5 percent:

(3) Ringing. (i) When LC ringing is generated at the remote end, it shall be automatic and intermittent and shall be cut off from the called line upon removal of the handset at the called station during either the ringing or silent period.

(ii) When ringing generators are provided in the LC on an ancillary basis, they shall be accepted or technically accepted by RUS.

(iii) Where ringing is generated at the remote end, the ringing system shall provide sufficient ringing on a bridged basis over the voltage and temperature limits of this specification and over subscriber loops within the limits stated by the manufacturer. The manufacturer shall state the minimum number (not less than two) of main station ringers that can be used for each ringing option available.

(g) Traffic. (1)(i) The minimum grade of service for traffic in the line concentrator shall be B =. 005 using the Traffic Table, based on the Erlang Lost-Calls-Cleared Formula. Required grade of service, traffic assumptions and calculations for the particular application being implemented shall be supplied by the bidder.

(ii) Service to customers served by a traffic sensitive LC should not be noticeably different than the service to customers served by the dedicated physical pairs from the central office so that uniform grade of service will be provided to all customers in any class of service. Reference § 1755.522(p)(1)(i), RUS General Specification for Digital, Stored Program Controlled Central Office Equipment.

(2) Traffic and Plant Registers. Traffic measurements consist of three types—peg count, usage, and congestion. A peg count register scores one count per call attempt per circuit group such as trunks, digit receivers, senders, etc. Usage counters measure the traffic density in networks, trunks and other circuit groups. Congestion registers score the number of calls which fail to find an idle circuit in a trunk group or to find an idle path through the switching network when attempting to connect two given end points. These conditions constitute “network blocking.”

(3) When required, traffic data will be stored in electronic storage registers or a block of memory consisting of one or more traffic counters for each item to be measured. The bidder shall indicate what registers are to be supplied, their purpose and the means for displaying the information locally (or at a remote location when available).

(h) Transmission requirements—(1) General. Unless otherwise stated, the requirements in paragraphs (h) (2) through (20) of this section are specified in terms of analog measurements made from Main Distributing Frame (MDF) terminals to MDF terminals excluding cabling loss.

(2) Telephone transmitter battery supply. A minimum of 20 milliamperes, dc, shall be provided for the transmitter of the telephone set at the subscriber station under all loop conditions specified by the bidder. The telephone set is assumed to have a resistance of 200 ohms.

(3) Impedance—subscriber loops. For the purpose of this section, the input impedance of all subscriber loops served by the equipment is arbitrarily considered to be 900 ohms in series with 2.16 microfarad capacitor at voice frequencies.

(4) Battery noise. Noise across the remote terminal battery at power panel distribution bus terminals shall not exceed 35 dBrnC during the specified busy hour.

(5) Stability. The long-term allowable variation in loss through the line concentrator system shall be ±0.5 dB from the loss specified by the bidder.

(6) Return loss. The specified return loss values are determined by the service and type of port at the measuring end. Two-wire ports are measured at 900 ohms in series with 2.16 microfarads, and 4-wire ports are measured at 600 ohms resistive. When other balance networks are supplied, test equipment arranged for operation with the supplied network(s) may be used. The requirement given shall meet the following cited values on each balance network available in the system:

Line-to-Line or Line-to-Trunk (2-Wire) Echo Return Loss (ERL)—18 dB, Minimum Singing Return Loss (SRL)—Low—15 dB, Minimum Singing Return Loss (SRL)—High—18 dB, Minimum

(7) Longitudinal balance. The minimum longitudinal balance, with dc loop currents between 20 to 70 mA, shall be 60 dB at all frequencies between 60 and 2000 Hz, 55 dB at 2700 Hz and 50 dB at 3400 Hz. The method of measurement shall be as specified in the IEEE standard 455, “Standard Testing Procedure for Measuring Longitudinal Balance of Telephone Equipment Operating in the Voice Band.” Source voltage level shall be 10 volts root mean square (rms) where conversation battery feed originates at the remote end.

(8) 60 hz longitudinal current immunity. The LC 60 Hz longitudinal current immunity shall be measured in accordance with Figure 1 of this section. Under test conditions cited on Figure 1 of this section, the system noise shall be 23 dBrnC or less as follows:

(9) Steady noise (idle channel at 900 ohm impedance). Steady noise: Measure on terminated call. Noise measurements shall comply with the following:

Maximum—23 dBrnC0 Average—18 dBrnC0 or Less 3KHz Flat—Less than 35 dBrnO as an Objective

(10) Impulse noise. LC central office terminal equipment shall have an impulse noise limit of not more than five counts exceeding 54 dBrnC0 voice band weighted in a 5-minute period on six such measurements made during the busy hour. A WILCOM T-194C Transmission Test Set, or equivalent, should be used for the measurements. The measurement shall be made by establishing a normal connection from the noise counter through the switching equipment in its off-hook condition to a quiet termination of 900 ohms impedance. Office battery and signaling circuit wiring shall be suitably segregated from voice and carrier circuit wiring, and frame talking battery filters provided, if and as required, in order to meet these impulse noise limits.

(11) Crosstalk coupling. Worst case equal level crosstalk shall be 65 dB minimum in the range 200 to 3400 Hz. This shall be measured between any two paths through the system by connecting a 0 dBm0 level tone to the disturbing pair.

(12) Digital error rate. The digital line concentrator shall not introduce more than one error in 10 8 bits averaged over a 5-minute period, excluding the least significant bit.

(13) Quantizing distortion. (i) The system shall meet the following requirements:

(ii) Due to possible loss of the least significant bit on direct digital connections, a signal to distortion degradation of up to 2 dB may be allowed where adequately justified by the bidder.

(14) Overload level. The overload level shall be + 3 dBm0.

(15) Gain tracking (linearity) shall meet the following requirements:

(16) Frequency response (loss relative to 1004 Hz) for line-to-line (via trunk group or intra-link) connections shall meet the following requirements:

(17) Envelope delay distortion. On any properly established connection, the envelope delay distortion shall not exceed the following limits:

(18) Absolute delay. The absolute one-way delay through the line concentrator, excluding delays associated with the central office switching equipment, shall not exceed 1000 microseconds analog-to-analog measured at 1800 Hz.

(19) Insertion loss. The insertion loss in both directions of transmission at 1004 Hz shall be included in the insertion loss requirements for the connected COE switch and shall not increase the overall losses through the combined equipment beyond the values for the COE alone, when operated through a direct digital interface. Systems operated with a (VF) line circuit interface may introduce up to 3 dB insertion loss. Reference § 1755.522(q)(3).

(20) Detailed requirements for direct digital connections. (i) This paragraph (h)(20) covers the detailed requirements for the provision of interface units which will permit direct digital connection between the host central office and line concentrator subscriber terminals over digital facilities. The digital transmission system shall be compatible with T1 type span lines using a DS1 interface and other digital interfaces that may be specified by the owner. The RUS specification for the T1 span line equipment is PE-60. Other span line techniques may also be used. Diverse span line routing may be used when specified by the owner.

(ii) The output of a digital-to-digital port shall be Pulse Code Modulation (PCM), encoded in eight-bit words using the mu-255 encoding law and D3 encoding format, and arranged to interface with a T1 span line.

(iii) Signaling shall be by means of Multifrequency (MF) or Dual Pulsing (DP) and the system which is inherent in the A and B bits of the D3 format. In the case where A and B bits are not used for signaling or system control, these bits shall only be used for normal voice and data transmission.

(iv) When a direct digital interface between the span line and the host central office equipment is to be implemented, the following requirements shall be met:

(A) The span line shall be terminated in a central office as a minimum a DS1 (1.544Mb/s) shall be provided;

(B) The digital central office equipment shall be programmed to support the operation of the digital port with the line concentrator subscriber terminal;

(C) The line concentrator subscriber terminal used with a direct digital interface shall be interchangeable with the subscriber terminal used with a central office terminal.

(i) Alarms. The system shall send alarms for such conditions as blown fuses, blocked controls, power failure in the remote terminal, etc., along with its own status indication and status of dry relay contact closures or solid-state equivalent to the associated central office alarm circuits. Sufficient system alarm points shall be provided from the remote terminal to report conditions to the central office alarm system. The alarms shall be transmitted from the remote terminal to the central office terminal as long as any part of the connecting link is available for this transmission. Fuses shall be of the alarm and indicator type, and their rating designated by numerals or color code on fuse positions.

(j) Electrical protection—(1) Surge protection. (i) Adequate electrical protection of line concentrator equipment shall be included in the design of the system. The characteristics and application of protection devices must be such that they enable the line concentrator equipment to withstand, without damage or excessive protector maintenance, the dielectric stresses and currents that are produced in line-to-ground and tip-to-ring circuits through the equipment as a result of induced or conducted lightning or power system fault-related surges. All wire terminals connected to outside plant wire or cable pairs shall be protected from voltage and current surges.

(ii) Equipment must pass laboratory tests, simulating a hostile electrical environment, before being placed in the field for the purpose of obtaining field experience. For acceptance consideration RUS requires manufacturers to submit recently completed results (within 90 days of submittal) of data obtained from the prescribed testing. Manufacturers are expected to detail how data and tests were conducted. There are five basic types of laboratory tests which must be applied to exposed terminals in an effort to determine if the equipment will survive. Figure 2 of this section, Summary of Electrical Requirements and Tests, identifies the tests and their application as follows:

(iii) Electrical protection requirements for line concentrator equipment can be summarized briefly as follows:

(A) Current surge tests simulate the stress to which a relatively low impedance path may be subjected before main frame protectors break down. Paths with a 100 Hz impedance of 50 ohms or less shall be subjected to current surges, employing a 10 × 1000 microsecond waveshape as defined in Figure 3 of this section, Surge Waveshape. For the purpose of determining this impedance, arresters which are mounted within the equipment are to be considered zero impedance. The crest current shall not exceed 500A; however, depending on the impedance of the test specimen this value of current may be lower. The crest current through the sample, multiplied by the sample's 100 Hz impedance, shall not exceed 1000 V. Where sample impedance is less than 2 ohms, peak current shall be limited to 500A as shown in Figure 4 of this section, Current Surge Tests. Figures 3 and 4 follow:

(B) Sixty Hertz (60 Hz) current carrying tests shall be applied to simulate an ac power fault which is conducted to the unit over the cable pairs. The test shall be limited to 10 amperes Root Mean Square (rms) of 60 Hz ac for a period of 11 cycles (0.1835 seconds) and shall be applied longitudinally from line to ground.

(C) AC power service surge voltage tests shall be applied to the power input terminals of ac powered devices to simulate switching surges or lightning-induced transients on the ac power system. The test shall employ a 1.2 × 50 microsecond waveshape with a crest voltage of 2500 V. Communications line protectors may be left in place for these tests.

(D) Voltage surge tests which simulate the voltage stress to which a relatively high impedance path may be subjected before primary protectors break down and protect the circuit. To ensure coordination with the primary protection while reducing testing to the minimum, voltage surge tests shall be conducted at a 1000 volts with primary arresters removed for devices protected by carbon blocks, or the + 3 sigma dc breakdown voltage of other primary arresters. Surge waveshape should be 10 × 1000 microseconds.

(E) Arrester response delay tests are designed to stress the equipment in a manner similar to that caused by the delayed breakdown of gap type arresters when subjected to rapidly rising voltages. Arresters shall be removed for these tests, the peak surge voltage shall be the + 3 sigma breakdown voltage of the arrester in question on a voltage rising at 100 V per microsecond, and the time for the surge to decay to half voltage shall equal at least the delay time of the tube as explained in Figure 5 of this section, Arrester Response Delay Time as follows:

(iv) Tests shall be conducted in the following sequence. As not all tests are required in every application, non-applicable tests should be omitted:

(A) Current Impulse Test;

(B) Sixty Hertz (60 Hz) Current Carrying Tests;

(C) AC Power Service Impulse Voltage Test;

(D) Voltage Impulse Test; and

(E) Arrester Response Delay Time Test.

(v) A minimum of five applications of each polarity for the surge tests and three for the 60 Hz Current Carrying Tests are the minimum required. All tests shall be conducted with not more than 1 minute between consecutive applications in each series of three or five applications to a specific configuration so that heating effects will be cumulative. See Figure 6 of this section, 60 Hz Current Surge Tests as follows:

(vi) Tests shall be applied between each of the following terminal combinations for all line operating conditions:

(A) Line tip to ring;

(B) Line ring to ground;

(C) Line tip to ground; and

(D) Line tip and ring tied together to ground.

(2) Dielectric strength. (i) Arresters shall be removed for all dielectric strength tests.

(ii) Direct current potentials shall be applied between all line terminals and the equipment chassis and between these terminals and grounded equipment housings in all instances where the circuitry is dc open circuit from the chassis, or connected to the chassis through a capacitor. The duration of all dielectric strength tests shall be at least 1 second. The applied potential shall be at a minimum equal to the plus 3 sigma dc breakdown voltage of the arrester, provided by the line concentrator manufacturer.

(3) Insulation resistance. Following the dielectric tests, the insulation resistance of the installed electrical circuits between wires and ground, with the normal equipment grounds removed, shall not be less than 10 megohms at 500 volts dc at a temperature of 68 °F (20 °C) and at a relative humidity of approximately 50 percent. The measurement shall be made after the meter stabilizes, unless the requirement is met sooner. Arresters shall be removed for these tests.

(4) Self-protection. (i) All components shall be capable of being continuously energized at rated voltage without injury. Design precautions must be taken to prevent damage to other equipment components when a particular component fails.

(ii) Printed circuit boards or similar equipment employing electronic components should be self-protecting against external grounds applied to the connector terminals. Board components and coatings applied to finished products shall be of such material or so treated that they will not support combustion.

(iii) Every precaution shall be taken to protect electrostatically sensitive components from damage during handling. This shall include written instructions and recommendations.

(k) Miscellaneous—(1) Interconnect wire. All interconnect wire shall be of soft annealed tinned copper wire meeting the requirements of ASTM Specification B33-91 and of suitable cross-section to provide safe current carrying capacity and mechanical strength. The insulation of installed wire, connected to its equipment and frames, shall be capable of withstanding the same insulation resistance and dielectric strength requirements as given in paragraphs (j)(2) and (j)(3) of this section at a temperature of 120 °F (49 °C), and a relative humidity of 90 percent.

(2) Wire wrapped terminals. These terminals are preferred and where used shall be of a material suitable for wire wrapping. The connections to them shall be made with a wire wrapping tool with the following minimum number of successive non-overlapping turns of bare tinned copper wire in contact with each terminal:

(i) 6 turns of 30 gauge;

(ii) 6 turns of 26 gauge;

(iii) 6 turns of 24 gauge; or

(iv) 5 turns of 22 gauge.

(3) Protection against corrosion. All metal parts of equipment frames, distributing frames, cable supporting framework and other exposed metal parts shall be constructed of corrosion resistant materials or materials plated or painted to render them adequately corrosion resistant.

(4) Screws and bolts. Screw threads for all threaded securing devices shall be of American National Standard form in accordance with Federal Standard H28, unless exceptions are granted to the manufacturer of the switching equipment. All bolts, nuts, screws, and washers shall be of nickel-copper alloy, steel, brass or bronze.

(5) Environmental requirements. (i) The bidder shall specify the environmental conditions necessary for safe storage and satisfactory operation of the equipment being bid. If requested, the bidder shall assist the owner in planning how to provide the necessary environment for the equipment.

(ii) To the extent practicable, the following temperature range objectives shall be met:

(A) For equipment mounted in central office and subscriber buildings, the carrier equipment shall operate satisfactory within an ambient temperature range of 32 °F to 120 °F (0 °C to 49 °C) and at 80 percent relative humidity between 50 °F and 100 °F (10 °C and 38 °C); and

(B) Equipment mounted outdoors in normal operation (with cabinet doors closed) shall operate satisfactorily within an ambient temperature range (external to cabinet) of −40 °F to 140 °F (−40 °C to 60 °C) and at 95 percent relative humidity between 50 °F to 100 °F (10 °C to 38 °C). As an alternative to the (60 °C) requirement, a maximum ambient temperature of 120 °F (49 °C) with equipment (cabinet) exposed to direct sunlight may be substituted.

(6) Stenciling. Equipment units and terminal jacks shall be adequately designated and numbered. They shall be stenciled so that identification of equipment units and leads for testing or traffic analysis can be made without unnecessary reference to prints or descriptive literature.

(7) Quantity of equipment bays. Consistent with system arrangements and ease of maintenance, space shall be provided on the floor plan for an orderly layout of future equipment bays. Readily accessible terminals will be provided for connection to interbay and frame cables to future bays. All cables, interbay and intrabay (excluding power), if technically feasible, shall be terminated at both ends by connectors.

(8) Radio and television interference. Measures shall be employed by the bidders to limit the radiation of radio frequencies generated by the equipment so as not to interfere with radio, television receivers, or other sensitive equipment.

(9) Housing. (i) When housed in a building supplied by the owner, a complete floor plan including ceiling height, floor loading, power outlets, cable entrances, equipment entry and travel, type of construction, and other pertinent information shall be supplied.

(ii) In order to limit corrosion, all metal parts of the housing and mounting frames shall be constructed of suitable corrosion resistant materials or materials protectively coated to render them adequately resistant to corrosion under the climatic and atmospheric conditions existing in the area in which the housing is to be installed.

(10) Distributing frame. (i) The line concentrator terminal equipment located at the central office shall be protected by the central office main distribution frame. The bidder may supply additional protection capability as appropriate. All protection devices (new or existing) shall be arranged to operate in a coordinated manner to protect equipment, limit surge currents, and protect personnel.

(ii) The distributing frame shall provide terminals for terminating all incoming cable pairs. Arresters shall be provided for all incoming cable pairs, or for a smaller number of pairs if specified.

(iii) The current carrying capacity of each arrester and its associated mounting shall coordinate with a #22 gauge copper conductor without causing a self-sustaining fire or permanently damaging other arrester positions. Where all cable pairs entering the housing are #24 gauge or finer, the arresters and mountings need only coordinate with #24 gauge cable conductors.

(iv) Remote terminal protectors may be mounted and arranged so that outside cable pairs may be terminated on the left or bottom side of protectors (when facing the vertical side of the MDF) or on the back surface of the protectors. Means for easy identification of pairs shall be provided.

(v) Protectors shall have a “dead front” (either insulated or grounded) where live metal parts are not readily accessible.

(vi) Protectors shall be provided with an accessible terminal of each incoming conductor which is suitable for the attachment of a temporary test lead. They shall also be constructed so that auxiliary test fixtures may be applied to open and test the subscriber's circuit in either direction. Terminals shall be suitable for wire wrapped connections or connectorized.

(vii) If specified, each protector group shall be furnished with a factory assembled tip cable for splicing to the outside cable; the tip cable shall be 20 feet (6.1 m) in length, unless otherwise specified. Tip cable used shall be RUS accepted.

(viii) Protector makes and types used shall be RUS accepted.

(l) Power equipment—(1) General. When specified, batteries and charging equipment shall be supplied for the remote terminal of the line concentrator.

(2) Operating voltage. (i) The nominal operating voltage of the central office and remote terminal shall be 48 volts dc, provided by a battery with the positive side tied to system ground.

(ii) Where equipment is dc powered, it must operate satisfactorily over a range of 50 volts ±6 volts dc.

(iii) Where equipment is ac powered, it must operate satisfactorily over a range of 120±10 volts or 220±10 volts ac.

(3) Batteries. (i) Unless otherwise specified by the owner, sealed batteries shall be supplied for the remote line concentrator terminal.

(ii) The batteries shall have an ampere hour load capacity of no less than 8 busy hours. When an emergency ac supply source is available, the battery reserve may be reduced to 3 busy hours.

(iii) The batteries shall be sealed when they are mounted in the cabinet with the concentrator equipment.

(iv) When specified by the owner, battery heaters shall be supplied in a bidder-furnished housing.

(4) Charging equipment. (i) One charger capable of carrying the full dc power load of the remote terminal shall be supplied unless otherwise specified by the owner.

(ii) Charging shall be on a full float basis. The rectifiers shall be of the full wave, self-regulating, constant voltage, solid-state type and shall be capable of being turned on and off manually.

(iii) When charging batteries, the voltage at the battery terminals shall be adjustable and shall be set at the value recommended for the particular battery being charged, provided it is not above the maximum operating voltage of the central office switching equipment. The voltage shall not vary more than ±0.02 volt dc per cell between 10% load and 100% load. Between 3% and 10% load, the output voltage shall not vary more than ±0.04 volt dc per cell. Beyond full load current the output voltage shall drop sharply. The above output voltage shall be maintained with input line voltage variations of plus or minus 10 percent. Provision shall be made to manually change the output voltage of the rectifier to 2.25 volts per cell to provide an equalization charge on the battery.

(iv) The charger noise, when measured with a suitable noise measuring set and under the rated battery capacitance and load conditions, shall not exceed 22 dBrnC. See Figure 7 of this section, Charger Noise Test as follows:

(v) The charging equipment shall be provided with a means for indicating a failure of charging current whether due to ac power failure, an internal failure in the charger, or to other circumstances which might cause the output voltage of the charger to drop below the battery voltage. Where a supplementary constant current charger is used, an alarm shall be provided to indicate a failure of the charger.

(vi) Audible noise developed by the charging equipment shall be kept to a minimum. Acoustic noise resulting from operation of the rectifier shall be expressed in terms of dB indicated on a sound level meter conforming to American National Standards Institute S1.4, and shall not exceed 65 dB (A-weighting) measured at any point 5 feet (1.5m) from any vertical surface of the rectifier.

(vii) The charging equipment shall be designed so that neither the charger nor the central office equipment is subject to damage in case the battery circuit is opened for any value of load within the normal limits.

(5) Power panel. (i) Battery and charger control switches, dc voltmeters, dc ammeters, fuses and circuit breakers, supervisory and timer circuits shall be provided as required. Portable or panel mounted frequency meters or voltmeters shall be provided as specified by the owner.

(ii) Power panels, cabinets and shelves, and associated wiring shall be designed initially to handle the line concentrator terminal when it reaches its ultimate capacity as specified by the owner.

(iii) The power panel shall be of the “dead front” type.

(6) Ringing equipment. The ringing system shall provide sufficient ringing on a bridged basis over the voltage and temperature limits of this section and over subscriber drops within the limits stated by the bidder. The ringing system shall be without operational problems such as bell tapping during dialing. The bidder shall state the minimum number (not less than two) of main station ringers that can be used for each ringing option available.

(7) Interrupter equipment. The interrupter may be an integral part of the system or may be part of the associated central office equipment connected to the line concentrator central office terminal.

(8) Special systems. Manufacturers of LC systems that operate by extending ringing current from the central office shall state their required input ringing (voltage and frequency) and the limitations on the connected subscriber loop.

(m) Fusing requirements—(1) General. (i) The equipment shall be completely wired and equipped with fuses, trouble signals, and all associated equipment for the wire capacity of the frames or cabinets provided.

(ii) Design precautions shall be taken to prevent the possibility of equipment damage arising from the insertion of an electronic package into the wrong connector or the removal of a package from any connector or improper insertion of the correct card in its connector.

(2) Fuses. Fuses and circuit breakers shall be of an alarm and indicator type, except where the fuse or breaker location is indicated on the alarm printout. Their rating shall be designated by numerals or color codes on the fuse or the panel.

(n) Trouble location and test—(1) Equipment. (i) Trouble indications in the system may be displayed in the form of lights on the equipment units or printed circuit boards.

(ii) When required, a jack or other connector shall be provided to connect a fault or trouble recorder (printer or display).

(2) Maintenance system. (i) The maintenance system shall monitor and maintain the system operation without interruption of call processing except for major failures.

(ii) The maintenance system shall be arranged to provide the ability to determine trouble to an individual card, functional group of cards, or other equipment unit.

(o) Spare parts. Lists of spare parts and maintenance tools as recommended by the bidder shall be provided. The cost of such tools and spare parts shall be indicated and shall not be included in the base price.

(p) Drawings and printed material. (1) The bidder shall supply instructional material for each line concentrator system involved at the time of delivery of the equipment. It is not the intent of this section to require system documentation necessary for the repair of individual circuit boards.

(2) Three complete sets of legible drawings shall be provided for each central office to be accessed. Each set shall include all of the following:

(i) Drawings of major equipment items such as frames, with the location of major component items of equipment shown therein;

(ii) Wiring diagrams indicating the specific method of wiring used on each item of equipment and interconnection wiring between items of equipment;

(iii) Maintenance drawings covering each equipment item that contains replaceable parts, appropriately identifying each part by name and part number; and

(iv) Job drawings including all drawings that are individual to the particular line concentrator involved such as mainframe, power equipment, etc.

(3) The following information shall also be furnished:

(i) A complete index of required drawings;

(ii) An explanation of electrical principles of operation of overall concentrator system;

(iii) A list of tests which can be made with each piece of test equipment furnished and an explanation of the method of making each test;

(iv) A sample of each form recommended for use in keeping records;

(v) The criteria for analyzing results of tests and determining appropriate corrective action;

(vi) A set of general notes on methods of isolating equipment faults to specific printed circuit cards in the equipment;

(vii) A list of typical troubles which might be encountered, together with general indications as to probable location of each trouble; and

(viii) All special line concentrator system grounding requirements.

(4) When installation is to be done by the bidder a complete set of drawings shall be provided by the owner, such as floor plans, lighting, grounding and ac power access.

(q) Installation and acceptance—(1) General. Paragraphs (q)(2)(i) through (q)(3)(xxi) of this section covers the general requirements for the installation of line concentrator equipment by the bidder, and outlines the general conditions to be met by the owner in connection with such installation work. The responsibilities apply in both the central office installation and remote terminal installations, unless otherwise noted.

(2) Responsibilities of owner. The owner shall:

(i) Allow the bidder and its employees free access to the premises and facilities at all hours during the progress of the installation;

(ii) Provide access to the remote site and any other site for development work needed during the installation;

(iii) Take such action as necessary to ensure that the premises are dry and free from dust and in such condition as not to be hazardous to the installation personnel or the material to be installed (not required when remote terminal is not installed in a building);

(iv) Provide heat or air conditioning when required and general illumination in rooms in which work is to be performed or materials stored;

(v) Provide suitable openings in buildings to allow material to be placed in position (not required when a remote terminal is not installed in a building);

(vi) Provide the necessary conduit and commercial and dc-ac inverter output power to the locations shown on the approved floor plan drawings;

(vii) Provide 110 volts a.c., 60 Hz commercial power equipped with a secondary arrester and a reasonable number of outlets for test, maintenance and installation equipment;

(viii) Provide suitable openings or channels and ducts for cables and conductors from floor to floor and from room to room;

(ix) Provide suitable ground leads, as designated by the bidder (not required when remote terminal is not installed in a building);

(x) Provide the necessary wiring, central office ground and commercial power service, with a secondary arrester, to the location of an exterior remote terminal installation based on the voltage and load requirements furnished voltage and load requirements furnished by the bidder;

(xi) Test at the owners expense all lines and trunks for continuity, leakage and loop resistance and ensure that all lines and trunks are suitable for operation with the central office and remote terminal equipment specified;

(xii) Make alterations and repairs to buildings necessary for proper installation of material, except to repair damage for which the bidder or its employees are responsible;

(xiii) Connect outside cable pairs on the distributing frame (those connected to protectors);

(xiv) Furnish all line, class of service assignment, and party line assignment information to permit bidder to program the data base memory within a reasonable time prior to final testing;

(xv) Release for the bidder's use, as soon as possible, such portions of the existing plant as are necessary for the proper completion of such tests as require coordination with existing facilities including facilities for T1 span lines with properly installed repeaters between the central office and the remote terminal installations;

(xvi) Make prompt inspections as it deems necessary when notified by the bidder that the equipment, or any part thereof, is ready for acceptance;

(xvii) Provide adequate fire protection apparatus at the remote terminal, including one or more fire extinguishers or fire extinguishing systems of the gaseous type, that has low toxicity and effect on equipment;

(xviii) Provide necessary access ports for cable, if underfloor cabling is selected;

(xix) Install equipment and accessory plant devices mounted external to the central office building and external to the repeater and other outside housings including filters, repeater housings, splicing of repeater cable stubs, externally mounted protective devices and other such accessory devices in accordance with written instructions provided by the bidder; and

(xx) Make all cross connections (at the MDF or Intermediate Distribution Frame IDF) between the physical trunk or carrier equipment and the central office equipment unless otherwise specified in appendix A of this section.

(3) Responsibilities of bidder. The bidder shall:

(i) Allow the owner and its representatives access to all parts of the building at all times;

(ii) Obtain the owner's permission before proceeding with any work necessitating cutting into or through any part of the building structure such as girders, beams, concrete or tile floors, partitions or ceilings (does not apply to the installation of lag screws, expansion bolts, and similar devices used for fastening equipment to floors, columns, walls, and ceilings);

(iii) Be responsible for and repair all damage to the building due to carelessness of the bidder's workforce, exercise reasonable care to avoid any damage to the owner's switching equipment or other property, and report to the owner any damage to the building which may exist or may occur during its occupancy of the building;

(iv) Consult with the owner before cutting into or through any part of the building structure in all cases where the fireproofing or moisture proofing may be impaired;

(v) Take necessary steps to ensure that all fire fighting apparatus is accessible at all times and all flammable materials are kept in suitable places outside the building;

(vi) Not use gasoline, benzene, alcohol, naphtha, carbon tetrachloride or turpentine for cleaning any part of the equipment;

(vii) Be responsible for delivering the CO and remote terminal equipment to the sites where they will be needed;

(viii) Install the equipment in accordance with the specifications for the line concentrator;

(ix) Have all leads brought out to terminal blocks on the MDF (or IDF if stated in appendix A of this section) and have all terminal blocks identified and permanently labeled;

(x) Use separate shielded type leads grounded at one end only unless otherwise specified by the owner or bidder or tip cables meeting RUS cable crosstalk requirements for carrier frequencies inside the central office;

(xi) Group the cables to separate carrier frequency, voice frequency, signaling, and power leads;

(xii) Make the necessary power and ground connections (location as shown in appendix A of this section) to the purchaser's power terminals and ground bus unless otherwise stated in appendix A of this section (ground wire shall be 6 AWG unless otherwise stated);

(xiii) Place the battery in service in compliance with the recommendations of the battery manufacturer;

(xiv) Make final charger adjustments using the manufacturer's recommended procedure;

(xv) Run all jumpers, except line and trunk jumpers (those connected to protectors) unless otherwise specified in appendix A of this section;

(xvi) Establish and update all data base memories with subscriber information as supplied by the owner until an agreed turnover time;

(xvii) Give the owner notice of completion of the installation at least one week prior to completion;

(xviii) Permit the owner or its representative to conduct tests and inspections after installation has been completed in order that the owner may be assured the requirements for installation are met;

(xix) Allow access, before turnover, by the owner or its representative, upon request, to the test equipment which is to be turned over as a part of the delivered equipment, to permit the checking of the circuit features which are being tested and to permit the checking of the amount of connected equipment to which the test circuits have access;

(xx) Notify the owner promptly of the completion of work of the central office terminals, remote terminals or such portions thereof as are ready for inspection; and

(xxi) Correct promptly all defects for which the bidder is responsible.

(4) Information to be furnished by bidder. The bidder shall accompany its bid with the following information:

(i) Two copies of the equipment list and the traffic calculations from which the quantities in the equipment list are determined;

(ii) Two copies of the traffic tables from which the quantities are determined, if other than the Erlang B traffic tables;

(iii) A block diagram of the line concentrator and associated maintenance equipment will be provided;

(iv) A prescribed method and criteria for acceptance of the completed line concentrator which will be subject to review;

(v) This special grounding requirements including the recommended configuration, suggested equipment and installation methods to be used to accomplish them;

(vi) The special handling and equipment requirements to avoid damage resulting from the discharge of static electricity (see paragraph (j)(4)(iii) of this section) or mechanical damage during transit installation and testing;

(vii) The location of technical assistance service, its availability and conditions for owner use and charges for the service by the bidder; and

(viii) The identification of the subscriber loop limits available beyond the line concentrator.

(5) Installation requirements. (i) All work shall be done in a neat, workmanlike manner. Equipment frames or cabinets shall be correctly located, carefully aligned, anchored, and firmly braced. Cables shall be carefully laid with sufficient radius of curvature and protected at corners and bends to ensure against damage from handling or vibration. Exterior cabinet installations for remote terminals shall be made in a permanent, eye-pleasing manner.

(ii) All multiple and associated wiring shall be continuous, free from crosses, reverses, and grounds and shall be correctly wired at all points.

(iii) An inspection shall be made by the owner or its representatives prior to performing operational and performance tests on the equipment, but after all installing operations which might disturb apparatus adjustments have been completed. The inspection shall be of such character and extent as to disclose with reasonable certainty any unsatisfactory condition of apparatus or equipment. During these inspections, or inspections for apparatus adjustments, or wire connections, or in testing of equipment, a sufficiently detailed examination shall be made throughout the portion of the equipment within which such condition is observed, or is likely to occur, to disclose the full extent of its existence, where any of the following conditions are observed:

(A) Apparatus or equipment units failing to compare in quantity and type to that specified for the installation;

(B) Apparatus or equipment units damaged or incomplete;

(C) Apparatus or equipment affected by rust, corrosion or marred finish; and

(D) Other adverse conditions resulting from failure to meet generally accepted standards of good workmanship.

(6) Operational tests. (i) Operational tests shall be performed on all circuits and circuit components to ensure their proper functioning in accordance with appropriate explanation of the operation of the circuit.

(ii) All equipment shall be tested to ensure proper operation with all components connected in all possible combinations and each line shall be tested for proper ring, ring trip and supervision.

(iii) All fuses shall be verified for continuity and correct rating. Alarm indication shall be demonstrated for each equipped fuse position. An already failed fuse compatible with the fuse position may be used.

(iv) Each alarm or signal circuit shall be checked for correct operation.

(v) A sufficient quantity of locally originating and incoming calls shall be made to demonstrate the function of the line concentrator including all equipped transmission paths. When intra-link calling is supplied, all intra-link transmission paths shall be demonstrated.

(7) Acceptance tests and data required. (i) Data shall be supplied to the owner by the bidder in writing as a part of the final documents in closing out the contract as follows:

(A) A detailed cross connect drawing of alarm to power board, central office battery to physical trunks or carrier system, wiring options used in terminals, channels, filters, repeaters, etc., marked in the owner's copy of the equipment manual or supplied separately;

(B) The measured central office supply voltages applied to the equipment terminals or repeaters at the time the jack and test point readings are made and ac supply voltages where equipment is powered from commercial ac sources;

(C) A list of all instruments, including accessories, by manufacturer and type number, used to obtain the data; and

(D) The measurements at all jack or test points recommended by the manufacturer, including carrier frequency level measurements at all carrier terminals and repeaters where utilized.

(ii) Data in the form of a checklist or other notations shall be supplied showing the results of the operational tests.

(iii) The bidder shall furnish to the owner a record of the battery cell or multicell unit voltages measured at the completion of the installation of the switching system before it is placed in commercial service. This is not required at a site where the owner furnishes dc power.

(8) Joint inspection requirements. (i) The bidder shall notify the owner in writing at least one week before the date the complete system will be ready for inspection and tests. A joint inspection shall be made by the bidder and the owner (or owner's engineer) to determine that the equipment installation is acceptable. The inspection shall include physical inspection, a review of acceptance test data, operational tests, and sample measurements.

(A) The owner shall review the acceptance test data and compare it to the requirements of this section.

(B) Sample measurements shall be made on all systems installed under this contract. Test methods should follow procedures described in paragraph (g)(5) of this section.

(C) A check shall be made of measured test point and jack readings for compliance with the manufacturer's specifications. This applies also to channels, terminals, carrier frequency repefault locating circuits.

(ii) In the event that the measured data or operational tests show that equipment fails to meet the requirements quirements of this section, the deficiencies are to be resolved as set forth in Article II of the 397 Special Equipment Contract. (Copies are available from RUS, room 0174, U.S. Department of Agriculture, Washington, DC 20250-1500.) The reports of the bidder and the owner shall be detailed as to deficiencies, causes, corrective action necessary, corrective action to be taken, completion time, etc.

(The information and recordkeeping requirements of this section have been approved by the Office of Management and Budget under the control number 0572-0059) Appendix A to § 1755.397—Specification for Line Concentrator Detailed Equipment Requirements (Information To Be Supplied by Owner) Telephone Company (Owner) Name: Location: Number of LC's Required: ________ Line Concentrator Locations:

Location	No. of Lines	Central Office

1. General

1.1 Notwithstanding the bidder's equipment lists, the equipment and materials furnished by the bidder must meet the requirements of paragraphs (a) through (p) of this section, and this appendix A.

1.2 Paragraph (a) through (p) of this section cover the minimum general requirements for line concentrator equipment.

1.3 Paragraph (q) of this section covers the requirements for installation, inspection and testing when such service is included as part of the contract.

1.4 This appendix A covers the technical data for application engineering and detailed equipment requirements insofar as they can be established by the owner. This appendix A shall be filled in by the owner.

1.5 Appendix B of this section covers detailed information on the line concentrator equipment, information on system reliability and traffic capacity as proposed by the bidder. Appendix B of this section is to be filled in by the bidder and must be presented with the bid.

Office Name (By Location) LC Designation 2. Number of Subscriber Lines

	Equipped	Wired only	Single-Party			Pay Station (Type:________)			Other (Describe:________)			Total

3. Loop Resistance

3.1 Number of non-pay station lines having a loop resistance, including the telephone set as follows:

3.1.1 For physical trunks between the remote and the office units, the loop resistance is to include the resistance of the trunk.

	No. of lines	1200-1900 ohms		1901-3200 ohms		3201-4500 ohms

3.1.2 Number of pay station lines having a loop resistance, excluding the telephone set, greater than:

	No. of lines	1200 ohms (Prepay)		1000 ohms (Semi-Postpay)

When physical trunks are used, these resistances include that of the facility between the CO and the remote.

3.1.3 Range extension equipment, if required, is to be provided:

________ By Bidder ________ By Owner (Quantity and Type) 4. Traffic Data

4.1 Average combined originating and terminating hundred call seconds (CCS) per line in the busy hour:

______ CCS/Line. (Assume originating & terminating equal.)

4.2 Percent Intra-Calling ________

4.3 Total Busy Hour Calls ________

5. TYPE or RINGING

5.1 Frequency No.	1.	2.	3.	4.	Frequency (Hz)					Max. No. of Phones/Freq.

5.2 Minimum ringing generator capacity to be supplied shall be sufficient to serve ________ lines (each frequency).

6. Central Office Equipment Interface

6.1 COE will be:

6.1.1 COE Manufacturer

Type Year Generic

6.1.2 ________ See digital central office specification for the switchboard at ____________________ .

6.2 Interface will be:

6.2.1 ________ Line Circuit(s) 6.2.2 ________ Direct Digital Interface 6.2.3 ________ Other (Describe)

6.3 Mounting rack for line concentrator furnished by:

________ Bidder ________ Owner (Specify width and height of rack available) (Width) (Height)

6.4 Equipment to be installed in existing building:

________ Yes (Attach detailed plan) ________ No 7. Transmission Facilities

7.1 Transmission facilities between the central office and remote terminals shall be:

7.1.1 Type:

________ VF Carrier Derived Circuits ________ Digital Span Line (DS1) ________ Other (Attach a layout of the transmission facilities between the central office and the remote terminals describing transmission and signaling parameters, routing and resistance where applicable.)

7.1.2 Utilizes physical plant

________ Cable Pairs (Existing/New) ________ Other Note:

Unless otherwise stated, physical plant will be supplied by the owner.

7.1.3 Terminal equipment for transmission facility to be supplied by:

________ Owner ________ Bidder

7.1.3.1 Carrier e/w voice terminations ________ Yes ________ No

Manufacturer and type Central office voice terminations Equipped ________, Wired Only ________

7.1.3.2 Digital span line (DS1) supplied by

________ Owner ________ Bidder Manufacturer and Type

7.1.3.3 Number of repeaters (per span line) ________

7.1.3.4 Diverse (alternate) span line routing required

________ Yes (Describe in Item 11) ________ No

7.1.3.5 Span line terminations only ________ Yes ________ No

7.1.3.6 Span line power required (CO and Remote Terminals) ________ Yes ________ No

7.1.3.7 Physical facility between CO and remote Loop Resistance ________ ohms, Length ________ meters

8. Power Equipment Requirements

8.1 Central Office Terminal

8.1.1 Owner-furnished −48 volt dc power ________ Yes ________ No

8.1.2 Other (Describe)

8.1.3 Standby power is available ________ Yes ________ No

8.2 Remote Terminal

8.2.1 Owner-furnished −48 vdc power ________ Yes ________ No

8.2.2 Bidder-furnished power supply ________ Yes ________ No

8.2.3 AC power available at site:

________ 110 vac, 60 Hz, single-phase ________ Other (Describe in Item 11)

8.2.4 A battery reserve of ________ busy hours shall be provided for this line concentrator terminal when it reaches ________ lines at the traffic rates specified.

8.2.5 Batteries supplied shall be:

________ Lead Calcium ________ Stabilized Electrolyte ________ Sealed Lead Acid ________ Other (Describe in item 11)

8.2.6 Standby power is available ________ Yes ________ No

9. Remote Terminal

9.1 Mounting

9.1.1 ________ Outside Housing (To be furnished by bidder)

9.1.2 ________ Concrete Slab to be furnished by owner (Bidder to supply construction details after award.)

9.1.3 ________ Manhole, environmentally controlled (Describe in Item 11)

9.1.4 ________ Pedestal Mounting

9.1.5 ________ Pole Mounting (Owner-furnished installed pole)

9.1.6 ________ Prefab Building (Owner-furnished site)

9.2 Equipment is to be installed in an existing building.

________ Yes ________ No (Attach detailed plan.)

9.3 Other (Describe)

10. Alternates 11. Explanatory Notes Appendix B to § 1755.397—Specification for Line Concentrators Detailed Requirements; Bidder Supplied Information Telephone Company (Owner) Name: Location: Line Concentrator Equipment Locations Central Office Terminal: Remote Terminal: 1. General

1.1 The equipment and materials furnished by the bidder must meet the requirements of paragraphs (a) through (p) of this section.

1.2 Paragraph (a) through (p) of this section cover the minimum general requirements for line concentrator equipment.

1.3 Paragraph (q) of this section covers requirements for installation, inspection and testing when such service is included as part of the contract.

1.4 Appendix A of this section covers the technical data for application engineering and detailed equipment requirements insofar as they can be established by the owner. Appendix A of this section is to be filled in by the owner.

1.5 This appendix B covers detailed information on the line concentrator equipment, information as to system reliability and traffic capacity as proposed by the bidder. This appendix B shall be filled in by the bidder and must be presented with the bid.

2. Performance Objectives

2.1 Reliability (See paragraph (c) of this section)

2.2 Busy Hour Load Capacity and Traffic Delay (See Paragraph (g) of this section)

3. Equipment Quantities Dependent on System Design

3.1 Transmission Facilities between the Central Office and Remote Terminals

Type	Quantity equipped	Quantity wired only

4. Power Requirements 4.1 Central Office Terminal Voltage Current Drain (Amps) Normal ________, Peak ________ Fuse Qty ________, Size ________, Type ________ Heat Dissipation (BTU/Hr.) ________ 4.2 Remote Terminal AC or DC Voltage Current Drain (Amps) Normal ________, Peak ________ Fuse Qty ________, Size ________, Type ________ Heat Dissipation (BTU/Hr.) ________

Power required for heating or cooling equipment in remote bidder-furnished housing

5. Temperature and Humidity Limitations 5.1 Temperature

	Central office	Remote*	Maximum °F (°C)			Minimum °F (°C)

5.2 Relative Humidity

	Central office	Remote*	Maximum			Minimum

* Show conditions outside bidder-furnished housing.

6. Explanatory Notes [60 FR 44729, Aug. 29, 1995, as amended at 69 FR 18803, Apr. 9, 2004]

Sections 1755.400 through 1755.407 cover the requirements for acceptance tests and measurements on installed copper and fiber optic telecommunications plant and equipment.

[62 FR 23960, May 2, 1997]

(a) Acceptance tests outlined in §§ 1755.400 through 1755.407 are applicable to plant constructed by contract or force account. This testing standard provides for the following:

(1) Specific types of tests or measurements for the different types of telecommunications plant and equipment;

(2) The method of measurement and types of measuring equipment;

(3) The expected results and tolerances permitted to meet the acceptable standards and objectives;

(4) Suggested formats for recording the results of the measurements and tests; and

(5) Some probable causes of nonconformance and methods for corrective action, where possible.

(b) Alternative methods of measurements that provide suitable alternative results shall be permitted with the concurrence of the Rural Utilities Service (RUS).

(c) For the purpose of this testing standard, a “measurement” shall be defined as an evaluation where quantitative data is obtained (e.g., resistance in ohms, structural return loss in decibels (dB), etc.) and a “test” shall be defined as an evaluation where no quantitative data is obtained (e.g., a check mark indicating conformance is usually the result of the test).

(d) The sequence of tests and measurements described in this standard have been prepared as a guide. Variations from the sequence may be necessary on an individual application basis.

(e) There is some overlap in the methods of testing shown; also, the extent of each phase of testing may vary on an individual basis. The borrower shall determine the overall plan of testing, the need and extent of testing, and the responsibility for each phase of testing.

[62 FR 23960, May 2, 1997]

(a) The resistance of the central office (CO) and the remote switching terminal (RST) ground shall be measured before and after it has been bonded to the master ground bar (MGB) where it is connected to the building electric service ground.

(b) The ground resistance of electronic equipment such as span line repeaters, carrier terminal equipment, concentrators, etc. shall be measured.

(c) Method of measurement. The connection of test equipment for the ground resistance measurement shall be as shown in Figure 1. Refer to RUS Bulletin 1751F-802, “Electrical Protection Grounding Fundamentals,” for a comprehensive discussion of ground resistance measurements.

(d) Test equipment. The test equipment for making this measurement is shown in Figure 1 as follows:

(e) Applicable results. (1) For the CO and RST, the resistance after the bond has been made to the MGB electric service ground shall not exceed 5 ohms. Where the measured ground resistance exceeds 5 ohms, the borrower shall determine what additional grounding, if any, shall be provided.

(2) For electronic equipment, the ground resistance shall not exceed 25 ohms. Where the measured ground resistance exceeds 25 ohms, the borrower shall determine what additional grounding, if any, shall be provided.

(3) When ground resistance measurements exceed the ground resistance requirements of paragraphs (e)(1) and (e)(2) of this section, refer to RUS Bulletin 1751F-802, “Electrical Protection Grounding Fundamentals,” for suggested methods of reducing the ground resistance.

(f) Data record. Results of the CO and RST ground resistance measurements shall be recorded. A suggested format similar to Format I, Outside Plant Acceptance Tests—Subscriber Loops, in § 1755.407 or a format specified in the applicable construction contract may be used. Results of the electronic equipment ground resistance measurements shall be recorded. A suggested format similar to Format II, Outside Plant Acceptance Tests—Trunk Circuits, in § 1755.407 or a format specified in the applicable construction contract may be used. Data showing approximate moisture content of the soil at the time of measurement, the temperature, the type of soil and a description of the test equipment used shall also be included.

(g) Probable causes for nonconformance. Refer to RUS Bulletin 1751F-802, “Electrical Protection Grounding Fundamentals,” and Telecommunications Engineering and Construction Manual (TE&CM) Section 810, “Electrical Protection of Electronic Analog and Digital Central Office Equipment,” for possible causes of nonconformance and suggested methods for corrective action.

[62 FR 23960, May 2, 1997]

(a) Shield or shield/armor continuity. (1) Tests and measurements shall be made to ensure that cable shields or shield/armors are electrically continuous. There are two areas of concern. The first is shield or shield/armor bonding within a pedestal or splice and the second is shield or shield/armor continuity between pedestals or splices.

(2) Measurement techniques outlined here for verification of shield or shield/armor continuity are applicable to buried cable plant. Measurements of shield continuity between splices in aerial cable plant should be made prior to completion of splicing. Conclusive results cannot be obtained on aerial plant after all bonds have been completed to the supporting strand, multigrounded neutral, etc.

(3) Method of measurement. (i) The shield or shield/armor resistance measurements shall be made between pedestals or splices using either a Wheatstone bridge or a volt-ohm meter. For loaded plant, measurements shall be made on cable lengths that do not exceed one load section. For nonloaded plant, measurements shall be made on cable lengths that do not exceed 5,000 feet (ft) (1,524 meters (m)). All bonding wires shall be removed from the bonding lugs at the far end of the cable section to be measured. The step-by-step measurement procedure shall be as shown in Figure 2.

(ii) Cable shield or shield/armor continuity within pedestals or splices shall be measured with a cable shield splice continuity test set. The step-by-step measurement procedure outlined in the manufacturer's operating instructions for the specific test equipment being used shall be followed.

(4) Test equipment. (i) The test equipment for measuring cable shield or shield/armor resistance between pedestals or splices is shown in Figure 2 as follows:

(ii) A cable shield splice continuity tester shall be used to measure shield or shield/armor continuity within pedestals or splices.

(5) Applicable results. (i) The shield or shield/armor resistance per 1000 ft and per kilometer (km) for cable diameters and types of shielding materials are given in Table 1 (English Units) and Table 2 (Metric Units), respectively as follows:

(ii) All values of shield and shield/armor resistance provided in Tables 1 and 2 in (a)(5)(i) of this section are considered approximations. If the measured value corrected to 68 °F (20 °C) is within #30 percent (%) of the value shown in Table 1 or 2, the shield and shield/armor shall be assumed to be continuous.

(iii) To correct the measured shield resistance to the reference temperature of 68 °F (20 °C) use the following formulae:

R68 = Rt/[1 + A(t − 68)] for English Units R20 = Rt/[1 + A(t − 20)] for Metric Units Where: R68 = Shield resistance corrected to 68 °F in ohms. R20 = Shield resistance corrected to 20 °C in ohms. Rt = Shield resistance at measurement temperature in ohms. A = Temperature coefficient of the shield tape. t = Measurement temperature in °F or (°C).

(iv) The temperature coefficients (A) for the shield tapes to be used in the formulae referenced in paragraph (a)(5)(iii) of this section are as follows:

(A) 5 and 10 mil copper = 0.0021 for English units and 0.0039 for Metric units;

(B) 8 mil coated aluminum and 8 mil coated aluminum/6 mil coated steel = 0.0022 for English units and 0.0040 for Metric units;

(C) 5 mil copper clad stainless steel and 5 mil copper clad alloy steel = 0.0024 for English units and 0.0044 for Metric units;

(D) 6 mil copper clad stainless steel = 0.0019 for English units and 0.0035 for Metric units; and

(E) 6 and 7 mil alloy 194 = 0.0013 for English units and 0.0024 for Metric units.

(v) When utilizing shield continuity testers to measure shield and shield/armor continuity within pedestals or splices, refer to the manufacturer's published information covering the specific test equipment to be used and for anticipated results.

(6) Data record. Measurement data from shield continuity tests shall be recorded together with anticipated Table 1 or 2 values (see paragraph (a)(5)(i) of this section) in an appropriate format to permit comparison. The recorded data shall include specific location, cable size, cable type, type of shield or shield/armor, if known, etc.

(7) Probable causes for nonconformance. Among probable causes for nonconformance are broken or damaged shields or shield/armors, bad bonding harnesses, poorly connected bonding clamps, loose bonding lugs, etc.

(b) Conductor continuity. After placement of all cable and wire plant has been completed and joined together in continuous lengths, tests shall be made to ascertain that all pairs are free from grounds, shorts, crosses, and opens, except for those pairs indicated as being defective by the cable manufacturer. The tests for grounds, shorts, crosses, and opens are not separate tests, but are inherent in other acceptance tests discussed in this section. The test for grounds, shorts, and crosses is inherent when conductor insulation resistance measurements are conducted per paragraph (c) of this section, while tests for opens are inherent when tests are conducted for loop resistance, insertion loss, noise, or return loss measurements, per paragraphs (d), (e), or (f) of this section. The borrower shall make certain that all defective pairs are corrected, except those noted as defective by the cable manufacturer in accordance with the marking provisions of the applicable cable and wire specifications. All defective pairs that are not corrected shall be reported in writing with details of the corrective measures attempted.

(c) Dc insulation resistance (IR) measurement. (1) IR measurements shall be made on completed lengths of insulated cable and wire plant.

(2) Method of measurement. (i) The IR measurement shall be made between each conductor and all other conductors, sheath, shield and/or shield/armor, and/or support wire electrically connected together and to the main distributing frame (MDF) ground. The measurement shall be made from the central office with the entire length of the cable under test and, where used with all protectors and load coils connected. For COs containing solid state arresters, the solid state arresters shall be removed before making the IR measurements. Field mounted voice frequency repeaters, where used, may be left connected for the IR test but all carrier frequency equipment, including carrier repeaters and terminals, shall be disconnected. Pairs used to feed power remote from the CO shall have the power disconnected and the tip and ring conductors shall be opened before making IR tests. All conductors shall be opened at the far end of the cable being measured.

(ii) IR tests are normally made from the MDF with all CO equipment disconnected at the MDF, but this test may be made on new cables at field locations before they are spliced to existing cables. The method of measurement shall be as shown in Figure 3 as follows:

(iii) If the IR of the conductor cannot be measured because of breakdown of lightning arresters by the test voltage, the arrester units shall be removed and the conductor IR retested. If the IR then meets the minimum requirements, the conductor will be considered satisfactory. Immediately following the IR tests, all arrester units which have been removed shall be reinstalled.

(3) Test equipment. (i) IR measurements shall be made with either an insulation resistance test set or a direct current (dc) bridge type megohmmeter.

(ii) The IR test set shall have an output voltage not to exceed 500 volts dc and shall be of the hand cranked or battery operated type.

(iii) The dc bridge type megohmmeter, which may be alternating current (ac) powered, shall have scales and multiplier which make it possible to accurately read IR from 1 megohm to 1 gigohm. The voltage applied to the conductors under test shall not exceed “250 volts dc” when using an instrument having adjustable test voltage levels. This will help to prevent breakdown of lightning arresters.

(4) Applicable results. (i) For all new insulated cable or wire facilities, the expected IR levels are normally greater than 1,000 to 2,000 megohm-mile (1,609 to 3,218 megohm-km). A value of 500 megohm-mile (805 megohm-km) at 68 °F (20 °C) shall be the minimum acceptable value of IR. IR varies inversely with the length and the temperature.

(ii) The megohm-mile (megohm-km) value for a conductor may be computed by multiplying the actual scale reading in megohms on the test set by the length in miles (km) of the conductor under test.

(iii) The objective insulation resistance may be determined by dividing 500 by the length in miles (805 by the length in km) of the cable or wire conductor being tested. The resulting value shall be the minimum acceptable meter scale reading in megohms.

(iv) Due to the differences between various insulating materials and filling compounds used in manufacturing cable or wire, it is impractical to provide simple factors to predict the magnitude of variation in insulation resistance due to temperature. The variation can, however, be substantial for wide excursions in temperature from the ambient temperature of 68 °F (20 °C).

(v) Borrowers should be certain that tip and ring IR measurements of each pair are approximately the same. Borrowers should also be certain that IR measurements are similar for cable or wire sections of similar length and cable or wire type. If some pairs measure significantly lower, borrowers should attempt to improve these pairs in accordance with cable manufacturer's recommendations.

Note:

Only the megohm-mile (megohm-km) requirement shall be cause for rejection, not individual measurement differences.

(5) Data record. The measurement data shall be recorded. Suggested formats similar to Format I, Outside Plant Acceptance Tests—Subscriber Loops, or Format II, Outside Plant Acceptance Tests—Trunk Circuits, in § 1755.407 or formats specified in the applicable construction contract may be used.

(6) Probable causes for nonconformance. (i) When an IR measurement is below 500 megohm-mile (805 megohm-km), the cable or wire temperature at the time of testing must then be taken into consideration. If this temperature is well above 68 °F (20 °C), the measurement shall be disregarded and the cable or wire shall be remeasured at a time when the temperature is approximately 68 °F (20 °C). If the result is then 500 megohm-mile (805 megohm-km) or greater, the cable or wire shall be considered satisfactory.

(ii) Should the cable or wire fail to meet the 500 megohm-mile (805 megohm-km) requirement when the temperature is known to be approximately 68 °F (20 °C) there is not yet justification for rejection of the cable or wire. Protectors, lightning arresters, etc., may be a source of low insulation resistance. These devices shall be removed from the cable or wire and the cable or wire IR measurement shall be repeated. If the result is acceptable, the cable or wire shall be considered acceptable. The removed devices which caused the low insulation resistance value shall be identified and replaced, if found defective.

(iii) When the cable or wire alone is still found to be below the 500 megohm-mile (805 megohm-km) requirement after completing the steps in paragraph (c)(6)(i) and/or paragraph (c)(6)(ii) of this section, the test shall be repeated to measure the cable or wire in sections to isolate the piece(s) of cable or wire responsible. The cable or wire section(s) that is found to be below the 500 megohm-mile (805 megohm-km) requirement shall be either repaired in accordance with the cable or wire manufacturer's recommended procedure or shall be replaced as directed by the borrower.

(d) Dc loop resistance and dc resistance unbalance measurement. (1) When specified by the borrower, dc loop resistance and dc resistance unbalance measurements shall be made on all cable pairs used as trunk circuits. The dc loop resistance and dc resistance unbalance measurements shall be made between CO locations. Measurements shall include all components of the cable path.

(2) Dc loop resistance and dc resistance unbalance measurements shall be made on all cable pairs used as subscriber loop circuits when:

(i) Specified by the borrower;

(ii) A large number of long loops terminate at one location (similar to trunk circuits); or

(iii) Circuit balance is less than 60 dB when computed from noise measurements as described in paragraph (e) of this section.

(3) Dc resistance unbalance is controlled to the maximum possible degree by the cable specification. Allowable random unbalance is specified between tip and ring conductors within each reel. Further random patterns should occur when the cable conductor size changes. Cable meeting the unbalance requirements of the cable specification may under some conditions result in unacceptable noise levels as discussed in paragraph (d)(6)(iii) of this section.

(4) Method of measurement. The method of measurement shall be as detailed in Figures 4 and 5.

(5) Test equipment. The test equipment is shown in Figures 4 and 5 as follows:

(6) Applicable results. (i) The measured dc loop resistance shall be within ±5% of the calculated dc loop resistance when corrected for temperature.

(ii) The calculated dc loop resistance is computed as follows:

(A) Multiply the length of each different gauge by the applicable resistance per unit length as shown in Table 3 as follows:

(B) Add the individual resistances for each gauge to give the total calculated dc loop resistance at a temperature of 68 °F (20 °C).

(C) Correct the total calculated dc loop resistance at the temperature of 68 °F (20 °C) to the measurement temperature by the following formulae:

Rt = R68 × [1 + 0.0022 × t − 68)] for English Units Rt = R20 × [1 + 0.0040 × (t − 20)] for Metric Units Where: Rt = Loop resistance at the measurement temperature in ohms. R68 = Loop resistance at a temperature of 68 °F in ohms. R20 = Loop resistance at a temperature of 20 °C in ohms. t = Measurement temperature in °F or (°C).

(D) Compare the calculated dc loop resistance at the measurement temperature to the measured dc loop resistance to determine compliance with the requirement specified in paragraph (d)(6)(i) of this section.

(iii) Resistance varies directly with temperature change. For copper conductor cables, the dc resistance changes by ±1% for every ±5 °F (2.8 °C) change in temperature from 68 °F (20 °C).

(iv) The dc resistance unbalance between the individual conductors of a pair shall not exceed that value which will result in a circuit balance of less than 60 dB when computed from noise measurements as described in paragraph (e) of this section. It is impractical to establish a precise limit for overall circuit dc resistance unbalance due to the factors controlling its contribution to circuit noise. These factors include location of the resistance unbalance in relation to a low impedance path to ground (close to the central office) and the magnitude of unbalance in short lengths of cable making up the total circuit length. The objective is to obtain the minimum unbalance throughout the entire circuit when it is ascertained through noise measurements that dc resistance unbalance may be contributing to poor cable balance.

(v) Pairs with poor noise balance may be improved by reversing tip and ring conductors of pairs at cable splices. Where dc resistance unbalances are systematic over the total trunk circuit or loop circuit length, tip and ring reversals may be made at frequent intervals. Where the unbalances are concentrated in a shorter section of cable, only one tip and ring reversal should be required. Concentrated dc resistance unbalance produces maximum circuit noise when located adjacent to the central office. Concentrated dc resistance unbalance will contribute to overall circuit noise at a point approximately two-thirds ( 2/3) of the distance to the subscriber. All deliberate tip and ring reversals shall be tagged and identified to prevent plant personnel from removing the reversals when resplicing these connections in the future. The number of tip and ring reversals shall be held to a minimum.

(vi) A systematic dc resistance unbalance can sometimes be accompanied by other cable parameters that are marginal. Among these are pair-to-pair capacitance unbalance, capacitance unbalance-to-ground, and 150 kilohertz (kHz) crosstalk loss. Engineering judgment has to be applied in each case. Rejection of cable for excessive dc resistance unbalance shall only apply to a single reel length, or shorter.

(7) Data record. The measurement data for dc loop resistance and dc resistance unbalance shall be recorded. Suggested formats similar to Format I for subscriber loops and Format II for trunk circuits in § 1755.407 or formats specified in the applicable construction contract may be used.

(8) Probable causes for nonconformance. Dc loop resistance and dc resistance unbalance are usually the result of the resistance of individual conductors used in the manufacture of the cable. Resistance unbalance can be worsened by defective splicing of the conductors (splicing connectors, improper crimping tool, etc.).

(e) Subscriber loop measurement (loop checking). (1) When specified by the borrower, insertion loss and noise measurements shall be performed on subscriber loops after connection of a line circuit to the loop by the one person method using loop checking equipment from the customer access location. For this method, the central office should be equipped with a 900 ohm plus two microfarad quiet termination and a milliwatt generator having the required test frequencies; or a portable milliwatt generator having the desired frequencies may be used, especially, where several small offices are involved.

(2) At a minimum, insertion loss and frequency response of subscriber loop plant shall be measured at 1,000, 1,700, 2,300, and 2,800 Hertz (Hz). When additional testing frequencies are desired, the additional frequencies shall be specified in the applicable construction contract.

(3) Measurements of insertion loss and noise shall be made on five percent or more of the pairs. A minimum of five pairs shall be tested on each route. Pairs shall be selected on a random basis with greater consideration in the selection given to the longer loops. Consideration shall be given to measuring a large percentage, up to 100 percent, of all loops.

(4) Method of measurement—(i) Insertion loss. The step-by-step measurement procedure shall be as shown in Figure 6. The output level of the milliwatt generator tones shall be determined prior to leaving the CO. This shall be accomplished by dialing the milliwatt generator number from a spare line at the MDF and measuring with the same equipment to be used in the tests at customer access locations. The output levels shall be recorded for reference later. Insertion loss measurements shall be made across the tip and ring terminals of the pair under test. Figure 6 is as follows:

(ii) Noise. The step-by-step measurement procedure shall be as shown in Figure 7. Prior to leaving the CO for testing, dial the 900 ohm plus two microfarad quiet termination from a spare pair and measure the termination to determine that it actually is quiet. Circuit noise (noise-metallic) shall be measured at the customer access location across the tip and ring terminals of the pair under test. Power influence (direct reading with loop checking equipment) shall be measured at the customer access location from tip and ring conductors-to-ground (this connection is completed via the test unit). The power influence measurement includes the entire talking connection from the quiet termination to the customer. (That is, the power influence measurement includes all the CO equipment which normally makes up the connection.) Figure 7 is as follows:

(5) Test equipment. (i) Loop checking equipment which is available from several manufacturers may be used for these measurements. The equipment should have the capability of measuring loop current, insertion loss, circuit noise (NM) and power influence (PI). The test equipment manufacturer's operating instructions shall be followed.

(ii) There should be no measurable transmission loss when testing through loop extenders.

(6) Applicable results—(i) Insertion loss. (A) For D66 loaded cables (a specific loading scheme using a 66 millihenry inductor spaced nominally at 4,500 ft [1,371 m] intervals) measured at a point one-half section length beyond the last load point, the measured nonrepeated insertion loss shall be within ±10% at 1000, 1700, 2300, and 2800 Hz, ±15% at 3400 Hz and ±20% at 4000 Hz of the calculated insertion loss at the same frequencies and temperature.

(B) For H88 loaded cables (a specific loading scheme using an 88 millihenry inductor spaced nominally at 6,000 ft [1,829 m] intervals) measured at a point one-half section length beyond the last load point, the measured nonrepeatered insertion loss shall be within ±10% at 1000, 1700, and 2300 Hz, ±15% at 2800 Hz, and ±20% at 3400 Hz of the calculated insertion loss at the same frequencies and temperature.

(C) For nonloaded cables, the measured insertion loss shall be within ±10% at 1000, 1700, 2300, and 2800 Hz, ±15% at 3400 Hz and ±20% at 4000 Hz of the calculated insertion loss at the same frequencies and temperature.

(D) For loaded cables, the calculated loss at each desired frequency shall be computed as follows:

(1) Multiply the length in miles (km) of each different gauge in the loaded portion of the loop (between the office and a point one-half load section beyond the furthest load point) by the applicable decibel (dB)/mile (dB/km) value shown in Table 4 or 5. This loss represents the total loss for each gauge in the loaded portion of the loop;

(2) Multiply the length in miles (km) of each different gauge in the end section or nonloaded portion of the cable (beyond a point one-half load section beyond the furthest load point) by the applicable dB/mile (dB/km) value shown in Table 6. This loss represents the total loss for each gauge in the nonloaded portion of the loop; and

(3) The total calculated insertion loss is computed by adding the individual losses determined in paragraphs (e)(6)(i)(D)(1) and (e)(6)(i)(D)(2) of this section.

(E) For nonloaded cables, the calculated loss at each desired frequency shall be computed by multiplying the length in miles (km) of each different gauge by the applicable dB/mile (dB/km) value shown in Table 6 and then adding the individual losses for each gauge to determine the total calculated insertion loss for the nonloaded loop.

(F) The attenuation information in Tables 4, 5, and 6 are based on a cable temperature of 68 °F (20 °C). Insertion loss varies directly with temperature. To convert measured losses for loaded cables to a different temperature, use the following value for copper conductors: For each ±5 °F (±2.8 °C) change in the temperature from 68 °F (20 °C), change the insertion loss at any frequency by ±1%. To convert measured losses for nonloaded cables to a different temperature, use the following value for copper conductors: For each ±10 °F (±5.6 °C) change in the temperature from 68 °F (20 °C), change the insertion loss at any frequency by ±1%. Tables 4, 5, and 6 are as follows:

(G) For loaded subscriber loops, the 1 kHz loss shall be approximately 0.45 dB per 100 ohms of measured dc loop resistance. This loss shall be the measured loss less the net gain of any voice frequency repeaters in the circuit. Testing shall also be conducted to verify that the loss increases gradually as the frequency increases. The loss on H88 loaded loops should be down only slightly at 2.8 kHz but drop rapidly above 2.8 kHz. The loss on D66 loaded loops shall be fairly constant to about 3.4 kHz and there shall be good response at 4.0 kHz. When voice frequency repeaters are in the circuit there will be some frequency weighting in the build-out network and the loss at the higher frequencies will be greater than for nonrepeatered loops.

(H) For nonloaded subscriber loops, the 1 kHz loss shall be approximately 0.9 dB per 100 ohms of measured dc loop resistance. Testing shall also be conducted to verify that the loss is approximately a straight line function with no abrupt changes. The 3 kHz loss should be approximately 70% higher than the 1 kHz loss.

(ii) Noise. The principal objective related to circuit noise (noise-metallic) and the acceptance of new plant is that circuit noise levels be 20 dBrnc or less (decibels above reference noise, C-message weighted (a weighting derived from listening tests, to indicate the relative annoyance or speech impairment by an interfering signal of frequency (f) as heard through a “500-type” telephone set)). For most new, properly installed, plant construction, circuit noise will usually be considerably less than 20 dBrnc unless there are unusually long sections of telephone plant in parallel with electric power facilities and/or power influence of paralleling electric facilities is abnormally high. When circuit noise is 20 dBrnc or less, the loop plant shall be considered acceptable. When measured circuit noise is greater than 20 dBrnc, loop plant shall still be considered acceptable providing circuit balance (power influence reading minus circuit noise readings) is 60 dB or greater and power influence readings are 85 dBrnc or greater. When circuit noise is greater than 20 dBrnc and circuit balance is less than 60 dB and/or power influence is less than 85 dBrnc, loop plant shall not be considered acceptable and the loop plant shall be remedied to make circuit balance equal to or greater than 60 dB.

(7) Data record. Measurement data shall be recorded. A suggested format similar to Format I for subscriber loops in § 1755.407 or a format specified in the applicable construction contract may be used.

(8) Probable causes for nonconformance—(i) Insertion loss. Some of the more common causes for failing to obtain the desired results may be due to reversed load coil windings, missing load coils, bridge taps between load coils, load coil spacing irregularities, excessive end sections, cables having high or low mutual capacitance, load coils having the wrong inductance, load coils inadvertently installed in nonloaded loops, moisture or water in cable, split pairs, and improperly spliced connections. The above factors can occur singularly or in combination. Experience to date indicates that the most common problems are missing load coils, reversed load coil windings or bridge taps.

(ii) Noise. Some of the common causes for failing to obtain the desired results may be due to high power influence from paralleling electrical power systems, poor telephone circuit balance, discontinuous cable shields, inadequate bonding and grounding of cable shields, high capacitance unbalance-to-ground of the cable pairs, high dc loop resistance unbalance, dc loop current less than 20 milliamperes, etc. The above factors can occur singularly or in combination. See TE&CM Section 451, Telephone Noise Measurement and Mitigation, for steps to be taken in reducing telecommunications line noise.

(f) One-person open circuit measurement (subscriber loops). (1) When specified by the borrower, open circuit measurements shall be made on all loaded and nonloaded subscriber loops upon completion of the cable work to verify that the plant is free from major impedance irregularities.

(2) For loaded loops, open circuit measurements shall be made using one of the following methods:

(i) Impedance or pulse return pattern, with cable pair trace compared to that of an artificial line of the same length and gauge. For best results, a level tracer or fault locator with dual trace capability is required;

(ii) Return loss using a level tracer, with cable pair compared to an artificial line of the same length and gauge connected in lieu of a Precision Balance Network (PBN). This method can be made with level tracers having only single trace capability; or

(iii) Open circuit structural return loss using a level tracer. This method can be made with level tracer having only single trace capability.

(3) Of the three methods suggested for loaded loops, the method specified in paragraph (f)(2)(ii) of this section is the preferred method because it can yield both qualitative and quantitative results. The methods specified in paragraphs (f)(2)(i) and (f)(2)(iii) of this section can be used as trouble shooting tools should irregularities be found during testing.

(4) For nonloaded loops, open circuit measurements shall be made using the method specified in paragraph (f)(2)(i) of this section.

(5) Method of measurement. Open circuit measurements shall be made at the CO on each loaded and nonloaded pair across the tip and ring terminals of the pair under test. All CO equipment shall be disconnected at the MDF for this test. For loaded loops containing voice frequency repeaters installed in the CO or field mounted, the open circuit measurement shall be made after the repeaters have been disconnected. Where field mounted repeaters are used, the open circuit measurement shall be made at the repeater location in both directions.

(i) Impedance or pulse return pattern. The step-by-step measurement procedure using the impedance or pulse return pattern for loaded and nonloaded loops shall be as shown in Figure 8. An artificial line of the same makeup as the cable to be tested shall be set up. The traces of the impedance or pulse return pattern from the cable pair and the artificial line shall be compared and should be essentially identical. If the impedance or pulse return traces from the cable pair are different than the artificial line trace, cable faults are possible. When the cable pair trace indicates possible defects, the defects should be identified and located. One method of identifying and locating defects involves introducing faults into the artificial line until its trace is identical with the cable trace.

(ii) Return loss balanced to artificial line. The step-by-step measurement procedure using the return loss balanced to artificial line for loaded loops shall be as shown in Figure 9. An artificial line of the same makeup as the cable to be tested shall be set up. The artificial line is connected to the external network terminals of the test set. The cable pair under test is compared to this standard. When defects are found, they should be identified and located by introducing faults into the artificial line. This is more difficult than with the method referenced in paragraph (f)(5)(i) of this section since this measurement is more sensitive to minor faults and only a single trace is used.

(iii) Open circuit structural return loss using level tracer. The step-by-step measurement procedure using the level tracer for loaded loops shall be as shown in Figure 10. The cable pair is compared to a PBN.

(6) Test equipment. Equipment for performing these tests is shown in Figures 8 through 10. For loaded loops, artificial loaded lines must be of the same gauge and loading scheme as the line under test. For nonloaded loops, artificial nonloaded lines must be of the same gauge as the line under test. Artificial lines should be arranged using switches or other quick connect arrangements to speed testing and troubleshooting. Figures 8 through 10 are as follows:

(7) Applicable results. (i) For loaded and nonloaded loops, the two traces in the pulse return pattern or impedance method (paragraph (f)(5)(i) of this section) shall be essentially identical. The degree of comparison required of the two traces is to be determined by experience.

(ii) For loaded loops, results for return loss measurements using a level tracer, with artificial line, in lieu of a PBN (paragraph (f)(5)(ii) of this section) shall meet the following requirements:

(A) For D66 and H88 loaded cables the structural return loss (SRL) values shall range between 28 and 39 dB, respectively, at the critical frequency of structural return loss (CFSRL) within the pass band of the loading system being used. The minimum SRL value for uniform gauge shall be 25 dB CFSRL. These SRL values apply for loaded cables of uniform gauge for the entire length of the subscriber loop circuit. Subscriber loop circuits shall meet the loading spacing deviations and the cable mutual capacitance requirements in the applicable RUS cable specifications;

(B) For mixed gauge loaded cables the SRL values shall be 25 and 27 dB CFSRL, respectively, and the minimum SRL value shall be 22 dB CFSRL; and

(C) The two traces in the pulse return pattern should be essentially identical. The degree of comparison required of the two traces is determined by experience.

(iii) For loaded loops, the results of open circuit structural return loss measurements using a level tracer (paragraph (f)(5)(iii) of this section) shall meet the following requirements. For D66 and H88 loaded cables with uniform or mixed gauges, the worst value allowed for measured open circuit structural return loss between 1,000-3,500 Hz and 1,000-3,000 Hz, respectively, shall be approximately 0.9 dB (round trip) for each 100 ohms outside plant dc loop resistance including the resistance of the load coils. The value of 0.9 dB per 100 ohms for the round trip loss remains reasonably accurate as long as:

(A) The subscriber end section of the loaded pair under test is approximately 2,250 ft (685 m) for D66 loading or 3,000 ft (914 m) for H88 loading in length; and

(B) The one-way 1,000 Hz loss does not exceed 10 dB.

(iv) For loaded loops, the measured value of open circuit structural return loss can only be as accurate as the degree to which the dc loop resistance of the loaded pair under test is known. Most accurate results shall be obtained when the dc loop resistance is known by actual measurements as described in paragraph (d) of this section. Furthermore, where the dc loop resistance is measured at the same time as the open circuit structural return loss, no correction for temperature is needed because the loss is directly proportional to the loop resistance. Where it is not practical to measure the dc loop resistance, it shall be calculated and corrected for temperature as specified in paragraph (d)(6)(ii) of this section. When measuring existing plant, care shall be taken to verify the accuracy of the records, if they are used for the calculation of the dc loop resistance. For buried plant, the temperature correction shall be based at the normal depth of the cable in the ground. (Temperature can be measured by boring a hole to cable depth with a ground rod, placing a thermometer in the ground at the cable depth, and taking and averaging several readings during the course of the resistance measurements.) For aerial cable it shall be based on the temperature inside the cable sheath.

(v) For loaded loops, the best correlation between the measured and the expected results shall be obtained when the cable is of one gauge, one size, and the far end section is approximately 2,250 ft (685 m) for D66 loading or 3,000 ft (914 m) for H88 loading. Mixing gauges and cable sizes will result in undesirable small reflections whose frequency characteristics and magnitude cannot be accurately predicted. In subscriber loop applications, cable gauge may be somewhat uniform but the cable pair size most likely will not be uniform as cable pair sizes taper off toward the customer access location and a downward adjustment of 1 dB of the allowed value shall be acceptable. “Long” end sections (as defined in TE&CM Section 424, “Guideline for Telecommunications Subscriber Loop Plant”) lower the expected value, a further downward adjustment of 3 dB in the allowed value shall be acceptable.

(vi) For loaded loops, the limiting factor when making open circuit structural return loss measurements is when the 1,000 Hz one-way loss of the loaded cable pair under test becomes 10 dB or greater; it becomes difficult to detect the presence of irregularities beyond the 10 dB point on the loop. To overcome this difficulty, loaded loops having a one-way loss at 1,000 Hz greater than 10 dB shall be opened at some convenient point (such as a pedestal or ready access enclosure) and loss measurements at the individual portions measuring less than 10 dB one-way shall be made separately. When field mounted voice frequency repeaters are used, the measurement shall be made at the repeater location in both directions.

(8) Data record. (i) When performing a pulse return pattern or impedance open circuit measurement on loaded and nonloaded loops, a “check mark” indicating that the pair tests good or an “X” indicating that the pair does not test good shall be recorded in the SRL column. A suggested format similar to Format I for subscriber loops in § 1755.407 or a format specified in the applicable construction contract may be used.

(ii) When performing open circuit return loss measurements using the return loss balanced to an artificial line or return loss using a level tracer on loaded loops, the value of the poorest (lowest numerical value) SRL and its frequency in the proper column between 1,000 and 3,500 Hz for D66 loading or between 1,000 and 3,000 Hz for H88 loading shall be recorded. A suggested format similar to Format I for subscriber loops in § 1755.407 or a format specified in the applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the more common causes for failing to obtain the desired results may be due to reversed load coil windings, missing load coils, bridge taps between load coils, load coil spacing irregularities, excessive end sections, cables having high or low mutual capacitance, load coils inadvertently installed in nonloaded loops, moisture or water in the cable, load coils having the wrong inductance, split pairs, and improperly spliced connectors. The above can occur singularly or in combination. Experience to date indicates that the most common problems are missing load coils, reversed load coil windings or bridge taps.

(g) Cable insertion loss measurement (carrier frequencies). (1) When specified by the borrower, carrier frequency insertion loss measurements shall be made on cable pairs used for T1, T1C, and/or station carrier systems. Carrier frequency insertion loss shall be made on a minimum of three pairs. Select at least one pair near the outside of the core unit layup. If the three measured pairs are within 10% of the calculated loss in dB corrected for temperature, no further testing is necessary. If any of the measured pairs of a section are not within 10% of the calculated loss in dB, all pairs in that section used for carrier transmission shall be measured.

(2) Method of measurement. The step-by-step method of measurement shall be as shown in Figure 11.

(3) Test equipment. The test equipment is shown in Figure 11 as follows:

(4) Applicable results. (i) The highest frequency to be measured is determined by the type of carrier system. For T1 type carrier, the highest frequency is normally 772 kHz. For T1C type carrier, the highest frequency is normally 1576 kHz. The highest frequency to be measured for station carrier is 140 kHz.

(ii) The measured insertion loss of the cable shall be within ±10% of the calculated loss in dB when the loss is corrected for temperature.

(iii) The calculated insertion loss is computed as follows:

(A) Multiply the length of each different gauge by the applicable dB per unit length as shown in Table 7 or 8 as follows:

(B) Add the individual losses for each gauge to give the total calculated insertion loss at a temperature of 68 °F (20 °C);

(C) Correct the total calculated insertion loss at the temperature of 68 °F (20 °C) to the measurement temperature by the following formulae:

At = A68 × [1 + 0.0012 × (t − 68)] for English Units At = A20 × [1 + 0.0022 × (t − 20)] for Metric Units Where: At = Insertion loss at the measurement temperature in dB. A68 = Insertion loss at a temperature of 68 °F in dB. A20 = Insertion loss at a temperature of 20 °C in dB. t = Measurement temperature in °F or (°C); and

(D) Compare the calculated insertion loss at the measurement temperature to the measured insertion loss to determine compliance with the requirement specified in paragraph (g)(4)(ii) of this section. (Note: Attenuation varies directly with temperature. For each ±10 °F (5.6 °C) change in temperature increase or decrease the attenuation by ±1%.)

(iv) If the measured value exceeds the ±10% allowable variation, the cause shall be determined and corrective action shall be taken to remedy the problem.

(5) Data record. Results of carrier frequency insertion loss measurements for station, T1, and/or T1C type carrier shall be recorded. Suggested formats similar to Format III, Outside Plant Acceptance Tests—T1 or T1C Carrier Pairs, and Format IV, Outside Plant Acceptance Tests—Station Carrier Pairs, in § 1755.407 or formats specified in the applicable construction contract may be used.

(6) Probable causes for nonconformance. If the measured loss is low, the cable records are likely to be in error. If the measured loss is high, there may be bridge taps, load coils or voice frequency build-out capacitors connected to the cable pairs or the cable records may be in error. Figures 12 and 13 are examples that show the effects of bridge taps and load coils in the carrier path. Figures 12 and 13 are as follows:

[62 span 23962, May 2, 1997]

(a) Armor continuity. (1) Tests and measurements shall be made to ensure that the armor of fiber optic cables is continuous. There are two areas of concern. The first is armor bonding within a splice and the second is armor continuity between splices.

(2) Measurement techniques outlined here for verification of armor continuity are applicable to buried fiber optic cable plant. Measurements of armor continuity between splices in aerial, armored, fiber optic cable should be made prior to completion of splicing. Conclusive results cannot be obtained on aerial plant after all bonds have been completed to the supporting strand, multigrounded neutral, etc.

(3) Method of measurement. Armor continuity within splices shall be measured with a cable shield splice continuity test set. The step-by-step measurement procedure outlined in the manufacturer's operating instructions for the specific test equipment being used shall be followed.

(4) Test equipment. A cable shield splice continuity tester shall be used to measure armor continuity within splices.

(5) Applicable results. When utilizing shield continuity testers to measure armor continuity within splices, refer to the manufacturer's published information covering the specific test equipment to be used and for anticipated results.

(6) Data record. Measurement data from armor continuity tests shall be recorded together with anticipated values in an appropriate format to permit comparison. The recorded data shall include specific location, cable size, and cable type, if known, etc.

(7) Probable causes for nonconformance. Among probable causes for nonconformance are broken or damaged armors, bad bonding harnesses, poorly connected bonding clamps, loose bonding lugs, etc.

(b) Fiber optic splice loss measurement. (1) After placement of all fiber optic cable plant has been completed and spliced together to form a continuous optical link between end termination points, splice loss measurements shall be performed on all field and central office splice points.

(2) Method of measurement. (i) Field splice loss measurements shall be made between the end termination points at 1310 and/or 1550 nanometers for single mode fibers and in accordance with Figure 14. Two splice loss measurements shall be made between the end termination points. The first measurement shall be from termination point A to termination point B. The second measurement shall be from termination point B to termination point A.

(ii) CO splice loss measurements shall be made at 1310 and/or 1550 nanometers for single mode fibers and in accordance with Figure 15. Two splice loss measurements shall be made between the end termination points. The first measurement shall be from termination point A to termination point B. The second measurement shall be from termination point B to termination point A.

(3) Test equipment. The test equipment is shown in Figures 14 and 15. The optical time domain reflectometer (OTDR) used for the testing should have dual wave length capability. Figures 14 and 15 are as follows:

(4) Applicable results. (i) The splice loss for each single mode field splice shall be the bi-directional average of the two OTDR readings. To calculate the actual splice loss, substitute the OTDR readings maintaining the sign of the loss (+) or apparent gain (−) into the following equation:

(ii) When specified in the applicable construction contract, the splice loss of each field splice at 1310 and/or 1550 nanometers shall not exceed the limit specified in the contract.

(iii) When no limit is specified in the applicable construction contract, the splice loss of each field splice shall not exceed 0.2 dB at 1310 and/or 1550 nanometers.

(iv) The splice loss for each single mode CO splice shall be the bi-directional average of the two OTDR reading. To calculate actual splice loss, substitute the OTDR reading, maintaining the sign of the loss (+) or apparent gain (−), into the equation specified in paragraph (b)(4)(i) of this section.

(v) When specified in the applicable construction contract, the splice loss of each central office splice at 1310 and/or 1550 nanometers shall not exceed the limit specified in the contract.

(vi) When no limit is specified in the applicable construction contract, the splice loss of each central office splice shall not exceed 1.2 dB at 1310 and/or 1550 nanometers.

(5) Data record. The measurement data shall be recorded. A suggested format similar to Format V, Outside Plant Acceptance Test—Fiber Optic Telecommunications Plant, in § 1755.407 or a format specified in the applicable construction contract may be used.

(6) Probable causes for nonconformance. When the results of the splice loss measurements exceed the specified limits the following factors should be checked:

(i) Proper end preparation of the fibers;

(ii) End separation between the fiber ends;

(iii) Lateral misalignment of fiber cores;

(iv) Angular misalignment of fiber cores;

(v) Fresnel reflection;

(vi) Contamination between fiber ends;

(vii) Core deformation; or

(viii) Mode-field diameter mismatch.

(c) End-to-end attenuation measurement. (1) After placement of all fiber optic cable plant has been completed and spliced together to form a continuous optical link between end termination points, end-to-end attenuation measurements shall be performed on each optical fiber within the cable.

(2) Method of measurement. For single mode fibers, the end-to-end attenuation measurements of each optical fiber at 1310 and/or 1550 nanometers in each direction between end termination points shall be performed in accordance with Figure 16.

(3) Test equipment. The test equipment is shown in Figure 16 as follows:

(4) Applicable results. The end-to-end attenuation of each single mode optical fiber at 1310 and/or 1550 nanometers shall not exceed the limits specified in the applicable construction contract.

(5) Data record. The measurement data shall be recorded. A suggested format similar to Format V for fiber optic telecommunications plant in § 1755.407 or on a format specified in the applicable construction contract may be used.

(6) Probable causes for nonconformance. Failure of each optical fiber to meet the end-to-end attenuation limit could be attributed to the following:

(i) Excessive field or central office splice loss;

(ii) Excessive cable attenuation; or

(iii) Damage to the fiber optic cable during installation.

(d) End-to-end fiber signature measurement. (1) After placement of all fiber optic cable plant has been completed and spliced together to form a continuous optical link between end termination points, end-to-end fiber signature testing shall be performed on each optical fiber within the cable.

(2) Method of measurement. For single mode fibers, the end-to-end fiber signature measurement of each optical fiber in each direction shall be performed between end termination points at 1310 and/or 1550 nanometers in accordance with Figure 17.

(3) Test equipment. The test equipment is shown in Figure 17 as follows:

(4) Applicable results. The appearance of each optical fiber between end termination points.

(5) Data record. Plot the trace of each optical fiber and retain as a permanent record for future comparison if needed.

(6) Probable causes for nonconformance. None.

[62 FR 23989, May 2, 1997; 62 FR 25017, May 7, 1997]

(a) The data transmission measurements listed in this section shall be used to determine the acceptability of trunk and nonloaded subscriber loop circuits for data modem transmission.

(b) Signal-to-C notched noise (S/CNN) measurement. (1) When specified by the borrower, S/CNN measurements shall be made on trunk circuits and nonloaded subscriber loops. For trunk circuits, the measurement shall be made between CO locations. For nonloaded subscriber loops, the measurement shall be made from the CO to the station protector of the NID at the customer's access location.

(2) S/CNN is the logarithmic ratio expressed in dB of a 1,004 Hz holding tone signal compared to the C-message weighted noise level. S/CNN is one of the most important transmission parameters affecting the performance of data transmission because proper modem operation requires low noise relative to received power level. Since modulated carriers are used in data communication systems, noise measurements need to be performed with power on the connection to activate equipment having signal-level-dependent noise sources. For 4 kHz channels, a 1,004 Hz holding tone is used to activate the signal-dependent equipment on the channel or connection.

(3) Method of measurement. The S/CNN measurement shall be made using a 1,004 Hz holding tone at −13 dBm0 (decibels relative to one milliwatt, referred to a zero transmission level point) and performed in accordance with American National Standards Institute (ANSI) T1.506-1990, American National Standard for Telecommunications—Network Performance—Transmission Specifications for Switched Exchange Access Network including supplement ANSI T1.506a-1992, and American National Standards Institute/Institute of Electrical and Electronics Engineers (ANSI/IEEE) 743-1984, IEEE Standard Methods and Equipment for Measuring the Transmission Characteristics of Analog Voice Frequency Circuits. The ANSI T1.506-1990, American National Standard for Telecommunications—Network Performance—Transmission Specifications for Switched Exchange Access Network is incorporated by reference in accordance with 5 U.S.C. 522(a) and 1 CFR part 51. Copies of ANSI T1.506-1990 are available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from ANSI, Customer Service, 11 West 42nd Street, New York, New York 10036, telephone number (212) 642-4900. The ANSI/IEEE 743-1984, IEEE Standard Methods and Equipment for Measuring the Transmission Characteristics of Analog Voice Frequency Circuits is incorporated by reference in accordance with 5 U.S.C. 522(a) and 1 CFR part 51. Copies of ANSI/IEEE 743-1984 are available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration. Copies are available from ANSI, Customer Service, 11 West 42nd Street, New York, New York 10036, telephone number (212) 642-4900.

(4) Test equipment. The equipment for performing the measurement shall be in accordance with ANSI/IEEE 743-1984.

(5) Applicable results. The S/CNN for both trunk and nonloaded subscriber loop circuits shall not be less than 31 dB.

(6) Data record. The measurement data shall be recorded. Suggested formats similar to Format VI, Voiceband Data Transmission Tests—Nonloaded Subscriber Loops, and Format VII, Voiceband Data Transmission Tests—Trunk Circuits, in § 1755.407 or formats specified in the applicable construction contract may be used.

(7) Probable causes for nonconformance. Some of the causes for failing to obtain the desired results may be due to excessive harmonic distortion, quantizing noise, phase and amplitude jitter, and loss in digital pads used for level settings.

(c) Signal-to-intermodulation distortion (S/IMD) measurement. (1) When specified by the borrower, S/IMD measurements shall be made on trunk circuits and nonloaded subscriber loops. For trunk circuits, the measurement shall be made between CO locations. For nonloaded subscriber loops, the measurement shall be made from the CO to the station protector of the NID at the customer's access location.

(2) S/IMD is a measure of the distortion produced by extraneous frequency cross products, known as intermodulation products, when a multi-tone tone signal is applied to a system.

(3) Intermodulation distortion (IMD) is caused by system nonlinearities acting upon the harmonic frequencies produced from an input of multiple tones. The products resulting from IMD can be more damaging than noise in terms of producing data transmission errors.

(4) IMD is measured as a signal to distortion ratio and is expressed as the logarithmic ratio in dB of the composite power of four resulting test frequencies to the total power of specific higher order distortion products that are produced. The higher order products are measured at both the 2nd order and 3rd order and are designated R2 and R3, respectively. The four frequency testing for IMD is produced with four tones of 857, 863, 1,372, and 1,388 Hz input at a composite power level of −13 dBm0.

(5) Method of measurement. The S/IMD measurement shall be performed in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(6) Test equipment. The equipment for performing the measurement shall be in accordance with ANSI/IEEE 743-1984.

(7) Applicable results. The 2nd order (R2) S/IMD for both trunk and nonloaded subscriber loop circuits shall not be less than 40 dB. The 3rd order (R3) S/IMD for both trunk and nonloaded subscriber loop circuits shall not be less than 40 dB.

(8) Data record. The measurement data shall be recorded. Suggested formats similar to Format VI for nonloaded subscriber loops and Format VII for trunk circuits in § 1755.407 or formats specified in the applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the causes for failing to obtain the desired results may be due to channel nonlinearities, such as compression and clipping, which cause harmonic and intermodulation distortion in a voiceband signal.

(d) Envelope delay distortion (EDD) measurement. (1) When specified by the borrower, EDD measurements shall be made on trunk circuits and nonloaded subscriber loops. For trunk circuits, the measurement shall be made between CO locations. For nonloaded subscriber loops, the measurement shall be made from the CO to the station protector of the NID at the customer's access location.

(2) EDD is a measure of the linearity or uniformity of the phase versus frequency characteristics of a transmission facility. EDD is also known as relative envelope delay (RED).

(3) EDD is specifically defined as the delay relative to the envelope delay at the reference frequency of 1,704 Hz. EDD is typically measured at two frequencies, one low and one high in the voiceband. The low frequency measurement is made at 604 Hz. The high frequency measurement is made at 2,804 Hz.

(4) Method of measurement. The EDD measurement shall be performed in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(5) Test equipment. The equipment for performing the measurement shall be in accordance with ANSI/IEEE 743-1984.

(6) Applicable results. The EDD for both trunk and nonloaded subscriber loop circuits at the low frequency of 604 Hz shall not exceed 1,500 microseconds. The EDD for both trunk and nonloaded subscriber loop circuits at the high frequency of 2,804 Hz shall not exceed 1,000 microseconds.

(7) Data record. The measurement data shall be recorded. Suggested formats similar to Format VI for nonloaded subscriber loops and Format VII for trunk circuits in § 1755.407 or formats specified in the applicable construction contract may be used.

(8) Probable causes for nonconformance. Some of the causes for failing to obtain the desired results may be due to nonlinearity of the phase versus frequency characteristic of the transmission facility. This nonlinear phase versus frequency characteristic of the transmission facility causes the various frequency components to travel at different transit times which results in successively transmitted data pulses to overlap at the receive end. The overlapping of the pulses at the receive end results in distortion of the received signal. Excessive EDD on the transmission facility may be reduced using data modems with equalization or by conditioning the transmission line.

(e) Amplitude jitter (AJ) measurement. (1) When specified by the borrower, AJ measurements shall be made on trunk circuits and nonloaded subscriber loops. For trunk circuits, the measurement shall be made between CO locations. For nonloaded subscriber loops, the measurement shall be made from the CO to the station protector of the NID at the customer's access location.

(2) AJ is any fluctuation in the peak amplitude value of a fixed tone signal at 1,004 Hz from its nominal value. AJ is expressed in peak percent amplitude modulation.

(3) AJ is measured in two separate frequency bands, 4-300 Hz and 20-300 Hz. The 4-300 Hz band is important for modems employing echo canceling capabilities. The 20-300 Hz band is used for modems that do not employ echo cancelers.

(4) Amplitude modulation can affect the error performance of voiceband data modems. The measurement of amplitude jitter indicates the total effect on the amplitude of the holding tone of incidental amplitude modulation and other sources including quantizing and message noise, impulse noise, gain hits, phase jitter, and additive tones such as single-frequency interference.

(5) Method of measurement. The AJ measurement shall be performed in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(6) Test equipment. The equipment for performing the measurement shall be in accordance with ANSI/IEEE 743-1984.

(7) Applicable results. The AJ for both trunk and nonloaded subscriber loop circuits in the 4-300 Hz frequency band shall not exceed 6%. The AJ for both trunk and nonloaded subscriber loop circuits in the 20-300 Hz frequency band shall not exceed 5%.

(8) Data record. The measurement data shall be recorded. Suggested formats similar to Format VI for nonloaded subscriber loops and Format VII for trunk circuits in § 1755.407 or formats specified in the applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the causes for failing to obtain the desired results may be due to excessive S/CNN, impulse noise, and phase jitter.

(f) Phase jitter (PJ) measurement. (1) When specified by the borrower, PJ measurements shall be made on trunk circuits and nonloaded subscriber loops. For trunk circuits, the measurement shall be made between CO locations. For nonloaded subscriber loops, the measurement shall be made from the CO to the station protector of the NID at the customer's access location.

(2) PJ is any fluctuation in the zero crossings of a fixed tone signal (usually 1,004 Hz) from their nominal position in time within the voiceband. PJ is expressed in terms of either degrees peak-to-peak (° p-p) or in terms of a Unit Interval (UI). One UI is equal to 360° p-p.

(3) PJ measurements are typically performed in two nominal frequency bands. The frequency bands are 20-300 Hz band and either the 2-300 Hz band or the 4-300 Hz band. The 20-300 Hz band is important to all phase-detecting modems. The 4-300 Hz band or the 2-300 Hz band is important for modems employing echo canceling capabilities.

(4) Phase jitter can affect the error performance of voiceband data modems that use phase detection techniques. The measurement of phase jitter indicates the total effect on the holding tone of incidental phase modulation and other sources including quantizing and message noise, impulse noise, phase hits, additive tones such as single-frequency interference, and digital timing jitter.

(5) Method of measurement. The PJ measurement shall be performed in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(6) Test equipment. The equipment for performing the measurement shall be in accordance with ANSI/IEEE 743-1984.

(7) Applicable results. The PJ for both trunk and nonloaded subscriber loop circuits in the 4-300 Hz frequency band shall not exceed 6.5° p-p. The PJ for both trunk and nonloaded subscriber loop circuits in the 20-300 Hz frequency band shall not exceed 10.0° p-p.

(8) Data record. The measurement data shall be recorded. Suggested formats similar to Format VI for nonloaded subscriber loops and Format VII for trunk circuits in § 1755.407 or formats specified in the applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the causes for failing to obtain the desired results may be due to excessive S/CNN, impulse noise, and amplitude jitter.

(g) Impulse noise measurement. (1) When specified by the borrower, impulse noise measurements shall be made on trunk circuits and nonloaded subscriber loops. For trunk circuits, the measurement shall be made between CO locations. For nonloaded subscriber loops, the measurement shall be made from the CO to the station protector of the NID at the customer's access location.

(2) Impulse noise is a measure of the presence of unusually large noise excursions of short duration that are beyond the normal background noise levels on a facility. Impulse noise is typically measured by counting the number of occurrences beyond a particular noise reference threshold in a given time interval. The noise reference level is C-message weighted.

(3) Method of measurement. The impulse noise measurement shall be performed using a 1,004 Hz tone at −13 dBm0 and in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(4) Test equipment. The equipment for performing the measurement shall be in accordance with ANSI/IEEE 743-1984.

(5) Applicable results. The impulse noise for both trunk and nonloaded subscriber loop circuits shall not exceed 65 dBrnC0 (decibels relative to one picowatt reference noise level, measured with C-message frequency weighting, referred to a zero transmission level point). The impulse noise requirement shall be based upon a maximum of 5 counts in a 5 minute period at equal to or greater than the indicated noise thresholds.

(6) Data record. The measurement data shall be recorded. Suggested formats similar to Format VI for nonloaded subscriber loops and Format VII for trunk circuits in § 1755.407 or formats specified in the applicable construction contract may be used.

(7) Probable causes for nonconformance. Some of the causes for failing to obtain the desired results may be due to excessive transient signals originating from the various switching operations.

[62 FR 23996, May 2, 1997, as amended at 69 FR 18803, Apr. 9, 2004]

(a) Shield or armor ground resistance measurements shall be made on completed lengths of copper cable and wire plant and fiber optic cable plant.

(b) Method of measurement. (1) The shield or armor ground resistance measurement shall be made between the copper cable and wire shield and ground and between the fiber optic cable armor and ground, respectively. The measurement shall be made either on cable and wire lengths before splicing and before any ground connections are made to the cable or wire shields or armors. Optionally, the measurement may be made on cable and wire lengths after splicing, but all ground connections must be removed from the section under test.

(2) The method of measurement using either an insulation resistance test set or a dc bridge type megohmmeter shall be as shown in Figure 18 as follows:

(c) Test equipment. (1) The shield or armor ground resistance measurements may be made using an insulation resistance test set, a dc bridge type megohmmeter, or a commercially available fault locator.

(2) The insulation resistance test set should have an output voltage not to exceed 500 volts dc and may be hand cranked or battery operated.

(3) The dc bridge type megohmmeter, which may be ac powered, should have scales and multipliers which make it possible to accurately read resistance values of 50,000 ohms to 10 megohms. The voltage that is applied to the shield or armor during the test should not be less than “250 volts dc” nor greater than “1,000 volts dc” when using an instrument having adjustable test voltage levels.

(4) Commercially available fault locators may be used in lieu of the above equipment, if the devices are capable of detecting faults having resistance values of 50,000 ohms to 10 megohms. Operation of the devices and method of locating the faults should be in accordance with manufacturer's instructions.

(d) Applicable results. (1) For all new copper cable and wire facilities and all new fiber optic cable facilities, the shield or armor ground resistance levels normally exceed 1 megohm-mile (1.6 megohm-km) at 68 °F (20 °C). A value of 100,000 ohm-mile (161,000 ohm-km) at 68 °F (20 °C) shall be the minimum acceptable value of the shield or armor ground resistance.

(2) Shield or armor ground resistance varies inversely with length and temperature. In addition other factors which may affect readings could be soil conditions, faulty test equipment and incorrect test procedures.

(3) For the resistance test method and dc bridge type megohmmeter, the ohm-mile (ohm-km) value for the shield or armor ground resistance shall be computed by multiplying the actual scale reading in ohms on the test set by the length in miles (km) of the cable or wire under test.

(4)(i) The objective shield or armor ground resistance may be determined by dividing 100,000 by the length in miles (161,000 by the length in km) of the cable or wire under test. The resulting value is the minimum acceptable meter scale reading in ohms. Examples for paragraphs (d)(3) and (d)(4) of this section are as follows:

Equation 1. Test Set: Scale Reading * Length = Resistance-Length 75,000 ohms * 3 miles = 225,000 ohm-mile (75,000 ohms * 4.9 km = 367,000 ohm-km) Equation 2. 100,000 ohm-mile ÷ Length = Minimum Acceptable Meter Scale Reading 100,000 ohm-mile ÷ 3 miles = 33,333 ohms (161,000 ohm-km ÷ 4.9 km = 32,857 ohms)

(ii) Since the 33,333 ohms (32,857 ohms) is the minimum acceptable meter scale reading and the meter scale reading was 75,000 ohms, the cable is considered to have met the 100,000 ohm-mile (161,000 ohm-km) requirement.

(5) Due to the differences between various jacketing materials used in manufacturing cable or wire and to varying soil conditions, it is impractical to provide simple factors to predict the magnitude of variation in shield or armor to ground resistance due to temperature. The variations can, however, be substantial for wide excursions in temperature from the ambient temperature of 68 °F (20 °C).

(e) Data record. The data shall be corrected to the length requirement of ohm-mile (ohm-km) and a temperature of 68 °F (20 °C) and shall be recorded on a form specified in the applicable construction contract.

(f) Probable causes for nonconformance. (1) When results of resistance measurements are below the 100,000 ohm-mile (161,000 ohm-km) requirement at 68 °F (20 °C), the jacket temperature, soil conditions, test equipment and method shall be reviewed before the cable or wire is considered a failure. If the temperature is approximately 68 °F (20 °C) and soil conditions are acceptable, and a reading of less than 100,000 ohm-mile (161,000 ohm-km) is indicated, check the calibration of the equipment; as well as, the test method. If the equipment was found to be out of calibration, recalibrate the equipment and remeasure the cable or wire. If the temperature was 86 °F (30 °C) or higher, the cable or wire shall be remeasured at a time when the temperature is approximately 68 °F (20 °C). If the test was performed in unusually wet soil, the cable or wire shall be retested after the soil has reached normal conditions. If after completion of the above steps, the resistance value of 100,000 ohm-mile (161,000 ohm-km) or greater is obtained, the cable or wire shall be considered acceptable.

(2) When the resistance value of the cable or wire is still found to be below 100,000 ohm-mile (161,000 ohm-km) requirement after completion of the steps listed in paragraph (f)(1) of this section, the fault shall be isolated by performing shield or armor ground resistance measurements on individual cable or wire sections.

(3) Once the fault or faults have been isolated, the cable or wire jacket shall be repaired in accordance with § 1755.200, RUS Standard for Splicing Copper and Fiber Optic Cables or the entire cable or wire section may be replaced at the request of the borrower.

[62 FR 23998, May 2, 1997]

The following suggested formats listed in this section may be used for recording the test data:

[62 FR 24000, May 2, 1997]

(a) Sections 1755.501 through 1755.510 cover service installations at permanent or mobile home customer access locations. Sections 1755.501 through 1755.510 do not cover service installations at customer access locations associated with boat yards or marinas.

(b) Service installations for customer access locations in boat yards or marinas shall be performed in accordance with Article 800, Communications Circuits, of the American National Standards Institute/National Fire Protection Association (ANSI/NFPA) 70-1999, National Electrical Code ® (NEC ®). The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ® is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/NFPA 70-1999, NEC ®, are available for inspection during normal business hours at Rural Utilities Service (RUS), room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

For the purpose of this section and §§ 1755.502 through 1755.510, the following terms are defined as follows:

American National Standards Institute (ANSI). A private sector standards coordinating body which serves as the United States source and information center for all American National Standards.

Ampacity. As defined in the ANSI/NFPA 70-1999, NEC ®: The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.) The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/NFPA 70-1999, NEC ®, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

AWG. American Wire Gauge.

BET. Building entrance terminal.

Bonding (Bonded). As defined in the ANSI/NFPA 70-1999, NEC ®: The permanent joining of metallic parts to form an electrically conductive path that will ensure electrical continuity and the capacity to conduct safely any current likely to be imposed. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Bonding harness wire. A reliable electrical conductor purposefully connected between metal parts which are required to be electrically connected (bonded) to one another to ensure the metal parts are at similar electrical potential.

Building entrance terminal (BET). A BET is comprised of a housing suitable for indoor and outdoor installation which contains quick-connect or binding post terminals for terminating both telecommunications service cable conductors and inside wiring cable conductors. The BET also includes primary station protectors and a means of terminating the metallic shields of service entrance cables.

Demarcation point (DP). As defined in the Federal Communications Commission (FCC) rules in 47 CFR part 68: The point of demarcation or interconnection between telecommunications company communications facilities and terminal equipment, protective apparatus, or wiring at a subscriber's premises. Carrier-installed facilities at, or constituting, the demarcation point shall consist of wire or a jack conforming to subpart F of 47 CFR part 68. “Premises” as used herein generally means a dwelling unit, other building or a legal unit of real property such as a lot on which a dwelling unit is located, as determined by the telecommunications company's reasonable and nondiscriminatory standard operating practices. The “minimum point of entry” as used herein shall be either the closest practicable point to where the wiring crosses a property line or the closest practicable point to where the wiring enters a multiunit building or buildings. The telecommunications company's reasonable and nondiscriminatory standard operating practices shall determine which shall apply. The telecommunications company is not precluded from establishing reasonable clarifications of multiunit premises for determining which shall apply. Multiunit premises include, but are not limited to, residential, commercial, shopping center, and campus situations.

(1) Single unit installations. For single unit installations existing as of August 13, 1990, and installations installed after that date, the demarcation point shall be a point within 12 inches (in.) (305 millimeters (mm)) of the primary protector, where there is no protector, within 12 in. (305 mm) of where the telecommunications wire enters the customer's premises.

(2) Multiunit installations. (i) In multiunit premises existing as of August 13, 1990, the demarcation point shall be determined in accordance with the local carrier's reasonable and nondiscriminatory standard operating practices. Provided, however, that where there are multiple demarcation points within the multiunit premises, a demarcation point for a customer shall not be further inside the customer's premises than a point 12 in. (305 mm) from where the wiring enters the customer's premises.

(ii) In multiunit premises in which wiring is installed after August 13, 1990, including additions, modifications, and rearrangements of wiring existing prior to that date, the telecommunications company may establish a reasonable and nondiscriminatory practice of placing the demarcation point at the minimum point of entry. If the telecommunications company does not elect to establish a practice of placing the demarcation point at the minimum point of entry, the multiunit premises owner shall determine the location of the demarcation point or points. The multiunit premises owner shall determine whether there shall be a single demarcation point for all customers or separate such locations for each customer. Provided, however, that where there are multiple demarcation points within the multiunit premises, a demarcation point for a customer shall not be further inside the customer's premises than a point 12 in. (305 mm) from where the wiring enters the customer's premises.

DP. Demarcation point.

Eligible country. Any country that applies with respect to the United States an agreement ensuring reciprocal access for United States products and services and United States suppliers to the markets of that country, as determined by the United States Trade Representative.

FCC. Federal Communications Commission.

Fuse link. As defined in the ANSI/NFPA 70-1999, NEC ®: A fine gauge section of wire or cable that serves as a fuse (that is, open-circuits to interrupt the current should it become excessive) that coordinates with the telecommunications cable and wire plant, and protective devices. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Grounding conductor. As defined in the ANSI/NFPA 70-1999, NEC ®: A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Listed. As defined in the ANSI/NFPA 70-1999, NEC ®: Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or services meets identified standards or has been tested and found suitable for a specified purpose. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Manufactured home. As defined in the ANSI/NFPA 70-1999, NEC ®: A factory-assembled structure or structures that bears a label identifying it as a manufactured home that is transportable in one or more sections, that is built on a permanent chassis and designed to be used as a dwelling with or without a permanent foundation where connected to the required utilities, and includes the plumbing, heating, air conditioning, and electric systems contained therein. Unless otherwise indicated, the term “mobile home” includes manufactured homes. Fine Print Note (FPN) No. 1: See the applicable building code for definition of the term permanent foundation. FPN No. 2: See 24 CFR part 3280, Manufactured Home Construction and Safety Standards, of the Federal Department of Housing and Urban Development for additional information on the definition. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Mobile home. As defined in the ANSI/NFPA 70-1999, NEC ®: A factory-assembled structure or structures transportable in one or more sections that is built on a permanent chassis and designed to be used as a dwelling without a permanent foundation where connected to the required utilities, and includes the plumbing, heating, air-conditioning, and electric systems contained therein. Unless otherwise indicated, the term “mobile home” includes manufactured homes. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Motor home. As defined in the ANSI/NFPA 70-1999, NEC ®: A vehicular unit designed to provide temporary living quarters for recreational, camping, or travel use built on or permanently attached to a self-propelled motor vehicle chassis or on a chassis cab or van that is an integral part of the completed vehicle. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Network interface device (NID). A NID is comprised of a housing suitable for outdoor installation which contains a compartment accessible by only telecommunications employees which includes a primary station protector and the means for terminating telecommunications service wire conductors and metallic shields, and a compartment accessible by customers which includes an RJ-11 plug and jack of the type specified in the FCC rules in 47 CFR part 68.

NID. Network interface device.

Primary station protector. An assembly which complies with RUS Bulletin 345-39, RUS Specification for Telephone Station Protectors. Copies of RUS Bulletin 345-39 are available upon request from RUS, U.S. Department of Agriculture (USDA), 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

Qualified Installer. A person who has extensive installation experience, complete knowledge and understanding of RUS Bulletin 1751F-805, Electrical Protection At Customer Locations; RUS Bulletin 1753F-153 (RUS Form 515d), Specifications and Drawings for Service Installations at Customer Access Locations, and applicable portions of the ANSI/NFPA 70-1999, NEC ®, and ANSI/IEEE C2-1997, NESC. Copies of RUS Bulletins 1751F-805 and 1753F-153 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

Recreational vehicle. As defined in the ANSI/NFPA 70-1999, NEC ®: A vehicular-type unit primarily designed as temporary living quarters for recreational, camping, or travel use, which either has its own motive power or is mounted on or drawn by another vehicle. The basic entities are: travel trailer, camping trailer, truck camper, and motor home. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

RUS. Rural Utilities Service.

RUS accepted (material and equipment). Equipment which RUS has reviewed and determined that:

(1) Final assembly or manufacture of the equipment is completed in the United States, its territories and possessions, or in an eligible country;

(2) The cost of components within the material or equipment manufactured in the United States, its territories and possessions, or in an eligible country is more than 50 percent of the total cost of all components used in the material or equipment; and

(3) The material or equipment is suitable for use on systems of RUS telecommunications borrowers.

RUS technically accepted (material and equipment). Equipment which RUS has reviewed and determined that the material or equipment is suitable for use on systems of RUS telecommunications borrowers but the material or equipment does not satisfy both paragraphs (1) and (2) of this definition:

(1) Final assembly or manufacture of the equipment is not completed in the United States, its territories and possessions, or in an eligible country; and

(2) The cost of components within the material or equipment manufactured in the United States, its territories and possessions, or in an eligible country is 50 percent or less than the total cost of all components used in the material or equipment.

SEA. Service entrance aerial.

SEB. Service entrance buried.

Travel trailer. As defined in the ANSI/NFPA 70-1999, NEC ®: A vehicular unit, mounted on wheels, designed to provide temporary living quarters for recreational, camping, or travel use, of such size and weight as not to require special highway movement permits when towed by a motorized vehicle, and of gross trailer area less than 320 square feet (29.7 square meters). (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

Truck camper. As defined in the ANSI/NFPA 70-1999, NEC ®: A portable unit constructed to provide temporary living quarters for recreational, travel or camping use, consisting of a roof, floor, and sides, designed to be loaded onto and unloaded from the bed of a pick-up truck. (Reprinted with permission from NFPA 70-1999, the National Electrical Code ®, Copyright © 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.)

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

(a) Sections 1755.503 through 1755.510 cover approved methods of making service installations at customer access locations in telecommunications systems of RUS borrowers.

(b) Requirements in §§ 1755.503 through 1755.510 cover facilities of the type described in the FCC rules in 47 CFR part 68 for one and multi-party customer owned premises wiring.

[66 FR 43317, Aug. 17, 2001]

(a) For the purposes of this section and §§ 1755.504 through 1755.510, a NID shall be as defined in § 1755.501 and shall contain both a fuseless primary station protector and a modular plug and jack for each conductor pair, up to a maximum of 11 pairs, and shall be provided by the telecommunications company and used by customers.

(b) For the purposes of this section and §§ 1755.504 through 1755.510, BET shall be as defined in § 1755.501 and shall contain both primary station protectors and connector terminals for each conductor pair, of 12 or more pairs, and shall be provided by the telecommunications company and used by customers. The primary station protectors may be either fuseless or fused.

(c) The requirements provided in this section and §§ 1755.504 through 1755.510 have been designed to coordinate with the provisions of the ANSI/NFPA 70-1999, NEC ®, and the American National Standards Institute/Institute of Electrical and Electronics Engineers, Inc. (ANSI/IEEE) C2-1997, National Electrical Safety Code (NESC). The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, and the ANSI/IEEE C2-1997, NESC, are incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of ANSI/NFPA 70-1999, NEC ®, are available from NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/IEEE C2-1997, NESC, are available from IEEE Service Center, 455 Hoes Lane, Piscataway, New Jersey 08854, telephone number 1 (800) 678-4333. Copies of the ANSI/NFPA 70-1999, NEC ®, and the ANSI/IEEE C2-1997, NESC, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Most state and local authorities require that utility construction comply with either the ANSI/NFPA 70-1999, NEC ®, and ANSI/IEEE C2-1997, NESC, or some earlier editions of the ANSI/NFPA 70, NEC ®, and ANSI/IEEE C2, NESC. Some authorities have their own more stringent codes which may or may not be embellishments of the ANSI/NFPA 70, NEC ®, and ANSI/IEEE C2, NESC.

(d) RUS borrowers shall make certain that all construction financed with RUS loan funds comply with:

(1) The provisions of this section and §§ 1755.504 through 1755.510 and the ANSI/NFPA 70-1999, NEC ®, and ANSI/IEEE C2-1997, NESC codes, or any more stringent local codes; or

(2) The provisions of this section and §§ 1755.504 through 1755.510 with borrower added adjustments to bring construction into compliance with any more stringent local codes.

(e) This section and §§ 1755.504 through 1755.510 are intended primarily for the installer who will perform the work. It assumes that decisions regarding the selection of grounding electrodes, locations, and types of equipment have been made by the RUS borrower or the engineer delegated by the RUS borrower.

(f) Only a qualified installer as defined in § 1755.501 shall be assigned to make installations without advance planning and without direct supervision.

(g) This section and §§ 1755.504 through 1755.509 contain information which is normally not provided on the construction drawings which are included in § 1755.510.

(h) All work shall be conducted in a careful and professional manner. Service wire and cable shall not be trampled on, run over by vehicles, pulled over or around abrasive objects or otherwise subjected to abuse.

(i) When situations not covered by this section and §§ 1755.504 through 1755.510 arise, the RUS borrower or the engineer delegated by the borrower, shall specify the installation procedure to be used. The requirements of paragraph (j) of this section shall be complied with in every installation.

(j) NIDs, BETs, and fused primary station protectors shall be installed and grounded to meet the requirements of the ANSI/NFPA 70-1999, NEC ®, or local laws or ordinances, whichever are more stringent.

(k) Battery polarity and conductor identification shall be maintained throughout the system as indicated on construction drawings 815 and 815-1 contained in § 1755.510. Color codes and other means of conductor identification of buried and aerial service wires shall conform to the requirements of this section and §§ 1755.504 through 1755.510.

(l) All materials for which RUS makes acceptance determinations, such as service wires and cables, ground rods, ground rod clamps, etc., used in service entrance installations shall be RUS accepted or RUS technically accepted. Borrowers shall require contractors to obtain the borrower's approval before RUS technically accepted materials are to be used in service entrance installations. Borrower's shall also ensure that the cost of the RUS technically accepted materials are at least 6 percent less than the cost of equivalent RUS accepted materials, as specified in “Buy American” Requirement of the Rural Electrification Act of 1938, as amended (7 U.S.C. 903 note). Materials used in service entrance installations which are of the type which RUS does not make acceptance determinations shall be of a suitable quality for their intended application as determined by the RUS borrower or the engineer delegated by the RUS borrower.

(m) On completion of an installation, borrowers shall require the installer to make all applicable tests required by §§ 1755.400 through 1755.407, RUS standard for acceptance tests and measurements of telecommunications plant.

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

(a) The demarcation point (DP) provides the physical and electrical interface between the telecommunications company's facilities and the customer's premises wiring.

(b) The Federal Communications Commission (FCC) rules in 47 CFR part 68 require telecommunications providers to establish a “DP” which marks a separation of the provider's facilities from the customer's (owned) premises wiring and equipment.

(c) RUS borrowers shall observe the FCC DP requirement by installing NIDs, BETs, or fused primary station protectors when required by section 800-30(a)(2) of ANSI/NFPA 70-1999, NEC ®, at all new or significantly modified customer access locations which are financed with RUS loan funds. The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from NFPA, 1 Batterymarch Park, P. O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/NFPA 70-1999, NEC ®, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(d) For all customer access locations of less than 12 pairs, RUS borrowers shall establish DPs by using either NIDs or fused primary station protectors when required by section 800-30(a)(2) of ANSI/NFPA 70-1999, NEC ®. For customer access locations of 12 pairs or greater, RUS borrowers shall establish DPs using either NIDs, BETs, or fused primary station protectors when required by section 800-30(a)(2) of ANSI/NFPA 70-1999, NEC ®.

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

(a) Buried services of two or three pairs shall consist of Service Entrance Buried (SEB) assembly units, in accordance with RUS Bulletin 1753F-153 (RUS Form 515d), Specifications and Drawings for Service Installations at Customer Access Locations. The wire used for buried services shall conform to the requirements of § 1755.860, RUS specification for filled buried wires, and shall be RUS accepted or RUS technically accepted. The conductor size for two and three pair buried service wires shall be 22 American Wire Gauge (AWG). Copies of RUS Bulletin 1753F-153 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 690-2268.

(b) Buried services of six or more pairs shall be RUS accepted or RUS technically accepted 22 AWG filled buried cable conforming to the requirements of § 1755.390, RUS specification for filled telephone cables.

(c) Buried service wire or cable shall be terminated in buried plant housings using either splicing connectors or filled terminal blocks in accordance with the applicable paragraphs of § 1755.200, RUS standard for splicing copper and fiber optic cables.

(d) Buried service wire or cable shall be identified at buried plant housings in accordance with construction drawing 958 contained in § 1755.510.

(e) Buried service wire or cable shall be installed up to the building in the same general manner as buried exchange cable but in addition must meet the following requirements:

(1) Light weight lawn plows or trenchers shall be used;

(2) The shortest feasible route commensurate with the requirements of § 1755.508(i), (j), and (k), and paragraph (f)(1) of this section shall be followed;

(3) Buried service wire or cable shall be plowed or trenched to a depth of 12 in. (305 mm) or greater where practicable in soil, 36 in. (914 mm) in ditches, or 3 in. (76 mm) in rock. Depths shall be measured from the top of the wire or cable to the surface of the ground or rock;

(4) In the case of a layer of soil over rock either the minimum depth in rock measured to the surface of the rock, or the minimum depth in soil measured to the surface of the soil may be used; and

(5) Where adequate advance planning has been done, burial of telecommunications services jointly with electric power services may be feasible. If a decision has been reached by management to provide joint occupancy services, the services may be installed using the recommendations in RUS Bulletin 1751F-640, “Design of Buried Plant—Physical Considerations.” Copies of RUS Bulletin 1751F-640 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

(f) Buried service wire or cable shall be installed on or in buildings as follows:

(1) Each buried service wire or cable shall contact the building as close to the NID, BET, or fused primary station protector as practicable. Service wire or cable runs on buildings shall normally consist of a single vertical run held to the minimum practical length. Horizontal and diagonal runs shall not be permitted.

(2) Buried service wire or cable shall be located so as to avoid damage from lawn mowers, animals, gardening operations, etc.

(3) Buried service wire or cable shall be installed against a foundation wall or pillar to provide adequate support and mechanical protection.

(4) Where it is likely that the service wire or cable shall be subjected to mechanical damage, the wire or cable shall be enclosed in a guard in accordance with assembly unit drawing BM83 contained in § 1755.510.

(5) The first above-ground attachment for a buried service wire or cable, unless it is enclosed in a guard, shall not be more than 4 in. (100 mm) above final grade.

(6) Uninsulated attachment devices may be used to attach buried service wire and cable to masonry and other types of noncombustible buildings and on any type of building if fuseless primary station protectors incorporated in NIDs or BETs are used and installations fully comply with section 800-30(a)(1) of ANSI/NFPA 70-1999, NEC ®. The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1(800)344-3555. Copies of ANSI/NFPA 70-1999, NEC ®, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(7) Insulated attachments shall be used to separate service wires or cables from woodwork where section 800-30(a)(2) of ANSI/NFPA 70-1999, NEC ® requiring the use of fused primary station protectors must be observed.

(8) Minimum separation between buried service wire or cable and other facilities shall be as listed in Table 1, as follows:

(9) Wire and cable attachments to buildings for outside mounted NIDS, BETs, or fused primary station protectors shall be in accordance with construction drawing 962 contained in § 1755.510.

(10) Appropriate devices for attaching service wire or cable on or in buildings vary with the type of building construction and the wire or cable size. Figures 1 and 2 illustrate various types of anchoring devices and their applications. The size and type of fastening device for the wire or cable size and type of surface shall be in accordance with the manufacturer's recommendation; Figures 1 and 2 are as follows:

(11) Experience indicates that there are objections from many owners of buildings covered with aluminum or vinyl siding to the drilling of holes in the siding for the attachment of wires or cables, and NIDs, BETs, or fused primary station protectors. It is, therefore, important to obtain permission from the owner before drilling holes in such siding.

(12) If the NID, BET, or fused primary station protector must be mounted inside (not recommended by RUS), the service entrance into the building shall be installed in accordance with section 800-12(c) of ANSI/NFPA 70-1999, NEC ®. After pulling-in the wire or cable, the free space around the cable or wire shall be carefully sealed both outside and inside with a duct sealer that has RUS acceptance or RUS technical acceptance.

(13) If the customer requests an all buried installation for an alarm system or objects to above-ground facilities because of appearance and one-party service is involved, the entrance hole shall be made below grade as shown in sketch C of construction drawing 510-2 contained in § 1755.510. Care shall be exercised to prevent damage to the building foundation. The hole shall be sealed as specified in paragraph (f)(12) of this section. The installation shall comply with all the requirements of section 800-12(c) of ANSI/NFPA 70-1999, NEC ®.

(g) When the NID, BET, or fused primary station protector is to be installed inside the building, the installation shall comply with section 800-12(c) of ANSI/NFPA 70-1999, NEC ®, and the outside plant wire or cable shall preferably be installed in a rigid metal or intermediate metal conduit that is grounded to an electrode in accordance with section 800-40(b) of ANSI/NFPA 70-1999, NEC ®, as shown in sketch A of Figure 3 in paragraph (h)(2) of this section. The shield of the outside plant wire or cable shall be bonded to the grounding terminal of the NID, BET, or fused primary station protector which in turn shall be connected to the closest, existing, and accessible grounding electrode, of the electrodes cited in section 800-40(b) of ANSI/NFPA 70-1999, NEC ®.

(h) An inside NID, BET, or fused primary station protector installation may also be made without use of a rigid metal or intermediate metal conduit provided that the ingress of the outside plant wire or cable complies with section 800-12(c) of ANSI/NFPA 70-1999, NEC ®, and provided either of the following are observed:

(1) The NID, BET, or fused primary station protector is located as close as practicable to the point where the outside plant wire or cable emerges through an exterior wall. The length of outside plant wire or cable exposed within the building shall be as short as practicable but in no case shall it be longer than 50 feet (ft) (15.2 meters (m)) in accordance with the allowable exception No. 3 of section 800-50 of ANSI/NFPA 70-1999, NEC ®. See sketch B of Figure 3 in paragraph (h)(2) of this section. The shield of the outside plant wire or cable shall be bonded to the grounding terminal of the NID, BET, or fused primary station protector which in turn shall be connected to the closest, existing and accessible grounding electrode, of the electrodes cited in section 800-40(b) of ANSI/NFPA 70-1999, NEC ® (Fine print Note No. 2 of ANSI/NFPA 70-1999, NEC ®, section 800-50, warns that the full 50 ft (15.2 m) may not be authorized for outside unlisted cable (not in a metal or intermediate metal conduit) within a building if it is practicable to place the NID, BET, or fused primary station protector closer than 50 ft (15.2 m) to the cable entrance point, e.g., if there is an acceptable and accessible grounding electrode of the type cited in section 800-40(b) of ANSI/NFPA 70-1999, NEC ®, anywhere along the proposed routing of the outside cable within the building); or

(2) Where the NID, BET, or fused primary station protector must be located within the building remote from the entrance point and the entrance point of the outside plant wire or cable cannot be designed to be closer to the NID, BET, or fused primary station protector location, the outside plant wire or cable shall be spliced, as close as practicable to the point where the outside plant wire or cable emerges through an outside wall, to an inside wiring cable that is “Listed” as being suitable for the purpose in accordance with part E of article 800 of ANSI/NFPA 70-1999, NEC ®. The length of outside plant wire or cable exposed within the building shall be as short as practicable but in no case shall it be longer than 50 ft (15.2 m) in accordance with the allowable exception No. 3 of section 800-50 of ANSI/NFPA 70-1999, NEC ®. See sketch C of Figure 3. The shield of the outside plant wire or cable shall be bonded to the grounding terminal of the NID, BET, or fused primary station protector which in turn shall be connected to the closest, existing, and accessible grounding electrode, of the electrodes cited in section 800-40(b) of ANSI/NFPA 70-1999, NEC ® (Fine print Note No. 2 of the ANSI/NFPA 70-1999, NEC ®, section 800-50, warns that the full 50 ft (15.2 m) may not be authorized for outside unlisted cable (not in a metal or intermediate metal conduit) if it is practicable to place the NID, BET, or fused primary station protector closer than 50 ft (15.2 m) to the cable entrance point, e.g., if there is an acceptable and accessible grounding electrode of the type cited in section 800-40(b) of ANSI/NFPA 70-1999, NEC ®, anywhere along the proposed routing of the outside cable within the building). Figure 3 is as follows:

(i) The polarity of buried wire or cable “tip” and “ring” conductors shall be maintained by making the connections in accordance with Table 2, as follows:

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

(a) Aerial services of one through six pairs shall consist of Service Entrance Aerial (SEA) assembly units, in accordance with RUS Bulletin 1753F-153 (RUS Form 515d), Specifications and Drawings for Service Installations at Customer Access Locations. The wire used for aerial services shall conform to the requirements of §§ 1755.700 through 1755.704, RUS specification for aerial service wires, and shall be RUS accepted or RUS technically accepted. Copies of RUS Bulletin 1753F-153 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

(b) If aerial wire services are to be connected to aerial cable pairs, the NIDs or fused primary station protectors and grounds shall be installed and connected before the aerial service wires are attached to the customer's structure.

(c) Kinks or splices shall not be permitted in aerial service wire spans.

(d) Aerial service wires shall be run in accordance with the construction drawings contained in § 1755.510 and shall conform to all clearance requirements of the ANSI/NFPA 70-1999, NEC ®, and ANSI/IEEE C2-1997, NESC, or local laws or ordinances, whichever are the most stringent. The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, and ANSI/IEEE C2-1997, NESC, are incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies of ANSI/NFPA 70-1999, NEC ®, are available from NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/IEEE C2-1997, NESC, are available from IEEE Service Center, 455 Hoes Lane, Piscataway, New Jersey 08854, telephone number 1 (800) 678-4333. Copies of ANSI/NFPA 70-1999, NEC ®, and ANSI/IEEE C2-1997, NESC, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(e) Aerial service wire shall be installed using the maximum practicable sag consistent with the required ground clearance and good construction practices. In no event shall the minimum sags be less than the values shown on construction drawing 505 contained in § 1755.510 for various span lengths and loading areas provided. Span lengths shall not exceed 250 ft (76 m).

(f) To reduce vibration and galloping, aerial service wire shall be twisted one complete turn for each 10 ft (3 m) of span length at the time of installation.

(g) The methods of attaching aerial service wires at poles shall be as illustrated in construction drawings 503-2 and 504 contained in § 1755.510.

(h) Horizontal and vertical climbing spaces on poles used jointly with power circuits shall be provided in conformance with the requirements of Rule 236 of ANSI/IEEE C2-1997, NESC.

(i) Not more than four aerial service wires shall be distributed from any one 7/16 in. (10 mm) drive hook, or more than two aerial service wires from any one 5/16 in. (8 mm) drive hook. Aerial service wires and drive hooks shall be arranged so that the load does not pull the drive hook out of the pole. When more than one drive hook is required, the drive hooks shall be staggered with a minimum separation of 1 in. (25.4 mm) horizontally on centers and 1.5 in. (40 mm) vertically on centers. If drive hooks are placed within 3 in. (76 mm) of the top of the pole and on the opposite side of the pole's circumference, a vertical separation of at least 3 in. (76 mm) shall be provided. A drive hook shall not be placed on the top of a pole or stub pole.

(j) When connecting aerial service wires to cable pairs at terminals, sufficient slack shall be provided so that each aerial service wire shall reach any binding post position as shown on construction drawing 312-1 contained in § 1755.510.

(k) Aerial service wire attachments on utility poles and the manner of placing bridle rings and entering cable terminals shall be as shown on construction drawing 503-2 contained in § 1755.510.

(l) Not more than two conductors shall be connected to any terminal binding post. Where it is necessary to bridge more than two aerial service wires at the same closure, the aerial service wires shall be terminated in aerial service wire terminals connected in parallel with a No. 20 AWG bridle wire which shall be terminated on the binding posts of the filled terminal block.

(m) Where aerial service wire is attached to aerial plastic cable, it shall be brought directly into a ready-access closure and shall be terminated on the binding posts of the filled terminal block as shown on construction drawing 503-2 contained in § 1755.510.

(n) The conductor of copper coated steel reinforced aerial service wires identified by tracer ridges shall be used as the ring (negative battery) conductor of the pair, and shall normally be connected to the right or lower binding post of a pair on filled terminal blocks and NIDs or fused primary station protectors.

(o) Nonmetallic reinforced aerial service wire pair identification. (1) The tip and ring conductors of nonmetallic reinforced aerial service wires shall be identified in accordance with Table 3, as follows:

(2) The ring (negative battery) conductor of the pair shall normally be connected to the right or lower binding post of a pair on filled terminal blocks and NIDs or fused primary station protectors.

(p) When it is necessary to avoid intervening obstacles between a pole and a building, span clamp attachments shall be used to support the aerial service wires at points between the poles that are supporting the cable on the suspension strand as indicated by construction drawings 501-1 and 501-2 contained in § 1755.510.

(q) Aerial service wire strung from pole to pole shall be placed entirely below or entirely above any existing wire or cable. When adequate ground clearance can be obtained, preference shall be given to placing aerial service wire below wire and cable.

(r) When more than one aerial service wire is installed from pole to pole, the first aerial service wire shall be sagged in accordance with construction drawing 505 contained in § 1755.510. Succeeding aerial service wires shall be sagged with 2 in. (50.8 mm) more sag for each aerial service wire.

(s) Aerial service wire spans from pole lines to buildings shall follow the shortest feasible route commensurate with the requirements of paragraph (t) of this section and shall be sagged in accordance with construction drawing 505 contained in § 1755.510. The route shall avoid trees and other obstructions to the extent practicable. Where trees cannot be avoided, tree trimming permission shall be obtained from the owner or the owner's representative, and all limbs and foliage within 2 ft (600 mm) of the finally sagged wire shall be removed. If tree trimming permission cannot be obtained, the matter shall be referred to the borrower for resolution before proceeding with the installation.

(t) Aerial service wires shall contact buildings as closely as practicable at a point directly above the NID, or fused primary station protector. Generally, horizontal drop wire runs on buildings shall not exceed 20 ft (6 m). The warning given in § 1755.505(f)(11) regarding drilling holes in aluminum and vinyl siding applies also to attaching aerial service wires.

(u) The point of the first building attachment shall be located so that the aerial service wire will be clear of roof drainage points.

(v) Where practicable, aerial service wires shall pass under electrical guys, power distribution secondaries and services, tree limbs, etc.

(w) Aerial service wire shall not pass in front of windows or immediately above doors.

(x) Aerial service wires shall be routed so as to have a minimum clearance of 2 ft (600 mm) from any part of a short wave, ham radio, etc. antenna mast and a television antenna mast in its normal vertical position and of the possible region through which it sweeps when being lowered to a horizontal position.

(y) Aerial service wires shall be installed such that all clearances and separations comply with either section 237 of ANSI/IEEE C2-1997, NESC, or ANSI/NFPA 70-1999, NEC ®, or local laws or ordinances, whichever is the most stringent.

(z) Aerial service wire attachments to buildings shall be as follows:

(1) First attachments on buildings shall be made in accordance with construction drawings 506, 507, or 508-1 contained in § 1755.510, as applicable;

(2) Intermediate attachments on buildings shall be made in accordance with construction drawings 510 or 510-1 contained in § 1755.510; and

(3) Uninsulated attachments shall be permitted to be used as follows:

(i) Wherever NIDS are used as permitted by section 800-30(a)(1) of the ANSI/NFPA 70-1999, NEC ®; and

(ii) On masonry and other types of nonflammable buildings.

(aa) Insulated attachments shall be used on wooden frame, metallic siding and other types of combustible buildings where fused primary station protectors are used, as required by section 800-30(a)(2) of ANSI/NFPA 70-1999, NEC ®.

(bb) Aerial service wire runs on buildings shall be attached vertically and horizontally in a neat and most inconspicuous possible manner. See construction drawing 513 contained in § 1755.510. Horizontal runs on buildings are undesirable and shall be kept to a minimum. Diagonal runs shall not be made.

(cc) Aerial service wire runs on buildings shall be located so as not to be subjected to damage from passing vehicles, pedestrians, or livestock.

(dd) Minimum separation between aerial service wires and other facilities on or in buildings shall be in accordance with § 1755.505(f)(8), Table 1.

(ee) Appropriate devices for attaching aerial service wires to buildings vary with the type of building construction and with the type of customer access location equipment. Table 4 lists various types of attachments and their application with respect to construction, customer access location equipment, and proper mounting devices. Construction drawings 506 through 513 contained in § 1755.510 illustrate requirements with respect to various angles of service wire contacts and uses of various attachments. Table 4 is as follows:

Notes:

1. Screw dimensions are minimum. Where appropriate, either or both dimensions shall be increased. All wood screws for exterior use shall be stainless steel. All other exterior metal devices shall be stainless steel, zinc coated steel, silicon bronze, or corrosion resistant aluminum alloy.

2. Toggle bolt dimensions are minimum. Where appropriate, either or both dimensions shall be increased.

3. All devices should be attached to studding.

4. Screw-type devices shall be secured by means of expansion-type anchors. Equivalent manual or machine-driven devices may be used. Where toggle bolts are specified equivalent devices may be used.

5. Pilot holes shall be provided for screws and bridle rings in shingles and dropsiding.

6. Attachment device not applicable.

7. Attachment device applicable but no separate fastening device required.

8. To convert English units to Metric units use 1 in. = 25.4 mm.

(ff) Fastener spacings for vertical and horizontal runs on frame or masonry buildings shall not be more than 6 ft (2 m) apart. Fasteners should be spaced close enough to prevent the aerial service wire from “slapping” against the building during windy conditions.

(gg) When it is necessary to pass behind or around obstructions such as downspouts and vertical conduits, the aerial service wire shall be supported firmly with attachment devices placed not more than 6 in. (152 mm) from the obstruction as illustrated in Figures 4 and 5 of paragraph (hh) of this section. Preferably, the aerial service wire should be routed behind obstructions to minimize the possibility of mechanical damage to the aerial service wire in the event repair work to the obstruction is required.

(hh) When passing around building projections of masonry or wood or around corners, aerial service wires shall be installed as illustrated in Figures 5 and 6. Figures 4, 5, and 6 are as follows:

(ii) In areas where ice and snow conditions are severe, aerial service wires shall be located so that ice and snow falling from the roof will not strike the wires. However, where aerial service wires must pass under the sloping part of the roof, first attachments shall be made as close as practicable to the eaves.

(jj) If two aerial service wire spans are required to the same building, the first attachment shall be such that both aerial service wires can be attached at the same attachment device. Refer to construction drawing 508-1 contained in § 1755.510. Where more than two aerial service wires are required, additional attachment devices in the same general location on the building shall be used.

(kk) When two or more aerial service wire runs are required on the same building they shall share the same type of attachment devices.

(ll) Aerial service wire entrances to buildings shall conform to sketch B of construction drawing 510-2 contained in § 1755.510, unless the entrance is made through a conduit.

(mm) When the aerial service wire approaches the entrance hole from above, a 1.5 in. (40 mm) minimum drip loop shall be formed in accordance with sketch B of construction drawing 510-2 contained in § 1755.510.

(nn) If an entrance conduit which slopes upward from outside to inside is available and suitably located, it shall be used for the aerial service wire entrance.

[66 span 43317, Aug. 17, 2001, as amended at 69 span 18803, Apr. 9, 2004]

(a) Where more than six pairs are needed initially, and where an aerial service is necessary, the service shall consist of 22 AWG filled aerial cable of a pair size adequate for the ultimate anticipated service needs of the building. The cable shall comply with the requirements of § 1755.390, RUS specification for filled telephone cables, and shall be RUS accepted or RUS technically accepted.

(b) Aerial cable services shall be constructed in accordance with specific installation specifications prepared by the RUS borrower or the engineer delegated by the borrower.

(c) Unless otherwise specified in the installation specifications, aerial cable service installations shall meet the following requirements:

(1) Strand supported lashed construction shall be used.

(2) Where practicable a 5/16 in. (8 mm) utility grade strand and automatic clamps shall be used in slack spans to avoid damage to the building.

(3) Construction on poles shall comply with applicable construction drawings for regular line construction. Aerial service cable shall be spliced to the main cable in accordance with § 1755.200, RUS standard for splicing copper and fiber optic cables.

(4) Where practicable, aerial cable shall pass under electrical guys, distribution secondaries, and services.

(5) The suspension strand shall be attached to the building by wall brackets as indicated in Figure 7 as follows:

(i) If taut spans are necessary, appropriate size strand may be used if the pull is in line with one wall of the building, or within 20 degrees of being in line as illustrated in sketch A of Figure 7. If the angle of pull is greater than 20 degrees from the building, the wall bracket shall be reinforced against pullout by an arrangement equivalent to sketch B of Figure 7. Taut spans may be strung using the recommendations in RUS Bulletin 1751F-630, Design of Aerial Plant. The same tension as would be used in normal line construction so as not to exceed 60 percent of the breaking strength of the strand under maximum loading shall be used. Taut spans shall not exceed 100 ft (30.5 m) in length and the cable weight shall not exceed 1 pound/foot (lb/ft) [1.5 kilogram/meter (kg/m)] except when equivalent combinations of greater span lengths with cable weight less than 1 lb/ft (1.5 kg/m) are permissible. Copies of RUS Bulletin 1751F-630 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

(ii) When an attachment must be made to the face of a building wall away from a corner, a “U” type wall bracket shall be used as indicated in sketch C of Figure 7. Only slack span construction with 5/16 in. (8 mm) utility grade strand shall be permitted in this situation. The bail of the automatic clamp shall be protected by a wire rope thimble.

(6) Aerial cable shall be located on the rear or side of the building and shall be run only in a horizontal or a vertical direction. The cable route shall be selected so as to avoid building projections and obstructions to the extent practicable.

(7) Cable attachment devices shall be located on solid masonry or on studs of wood frame buildings. Cable attachment devices may be installed on sheet surface materials only when such materials are reinforced with a backing material which allows penetration and firm holding of the attachment devices through the backing material.

(8) The minimum separation on or in buildings between cable and other facilities shall be as indicated in § 1755.505(f)(8), Table 1.

(9) On horizontal runs, cable clamps shall be placed so that the attachment is below the cable. On vertical runs, cable clamps shall be placed so that the attachment is on the same side as horizontal runs. Cable clamps shall be placed on the inside of cable bends.

(10) On horizontal runs, cable clamps shall be placed not more than 16 in. (400 mm) apart for cable diameters equal to or greater than 1 in. (25.4 mm) and 24 in. (600 mm) apart for cable diameters less than 1 in. (25.4 mm).

(11) On vertical runs, cable clamps shall be approximately 24 in. (600 mm) apart for all sizes of cable.

(12) For the cable entrance, holes shall be bored slightly larger in diameter than the cable and shall slope upward from outside to inside. A duct sealer having RUS acceptance or RUS technical acceptance shall be applied to both ends of the hole after the cable is pulled in.

(13) Section 1755.505(g) and (h) shall also apply to aerial cable services.

[66 span 43317, Aug. 17, 2001]

(a) All customer access locations shall be protected.

(b) Customer access location protection shall consist of installing the telecommunications facilities with proper clearances and insulation from other facilities, providing primary voltage limiting protection, fuse links, NIDs, BETs, or fused primary station protectors, if required, and adequate bonding and grounding.

(c) All NIDs shall be RUS accepted or RUS technically accepted or the RUS borrower shall obtain RUS regional office approval on a case by case basis as applicable.

(d) All BETs shall be RUS accepted or RUS technically accepted.

(e) All fused primary station protectors shall be RUS accepted or RUS technically accepted.

(f) NIDs, BETs, or fused primary station protectors shall be mounted outside for all applications except for those described in paragraphs (g)(1) through (g)(3) of this section.

(g) NIDs, BETs, or fused primary station protectors may be mounted inside when:

(1) Large buildings are to be served and the customer requests an inside installation;

(2) Buried alarm circuits are requested by the subscriber; or

(3) The customer requests an all buried installation for appearance or to prevent the drilling of holes in aluminum or vinyl siding.

(h) Outside mounted NIDs, BETs, or fused primary station protectors shall be easily accessible and shall be located between 3 to 5 ft (1 to 1.5 m) above final grade.

(i) The locations of NIDs, BETs, or fused primary station protectors shall be selected with emphasis on utilizing the shortest primary station protector grounding conductor practicable and on grounding of the telecommunications primary station protector to the electric service grounding system established at the building served utilizing electrodes (c) through (g) cited in section 800-40(b)(1) of ANSI/NFPA 70-1999, NEC ®. The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from NFPA, 1 Batterymarch Park, P. O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/NFPA 70-1999, NEC ®, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(j) If access to the building electric service grounding system, as referenced in paragraph (i) of this section, is not possible or is not reasonable (telecommunications primary station protector grounding conductor will be longer than 10 ft (3 m)), the NID, BET, or fused primary station protector shall be located as close as practicable to electrodes (a) or (b) cited in section 800-40(b)(1) of ANSI/NFPA 70-1999, NEC ®.

(k) In addition, the NID, BET, or fused primary station protector shall be located in, on, or immediately adjacent to the structure or building to be served as close as practicable to the point at which the telecommunications service wire attaches to the building, making sure that the telecommunications primary station protector grounding conductor is connected to the closest, existing, and accessible electrode, of the electrodes cited in paragraph (i) or (j) of this section.

(l) For the preferred customer access location installation, the ANSI/NFPA 70-1999, NEC ®, permits the telecommunications grounding conductor to be connected to the metallic conduit, service equipment closure, or electric grounding conductor as shown in Figure 8 of paragraph (l)(2) of this section.

(1) Connections to metallic conduits shall be made by ground straps clamped over a portion of the conduit that has been cleaned by sanding down to bare metal.

(2) Connections to metallic service equipment closures shall be made by attaching a connector which is listed for the purpose by some organization acceptable to the local authority (State, county, etc.) per article 100 of ANSI/NFPA 70-1999, NEC ®, definition for “Listed” (for example connectors listed for the purpose by Underwriters Laboratories (UL)). Figure 8 is as follows:

(m) Where it is not possible to accomplish the objective of paragraphs (i), (j), and (k) of this section, interior metallic pipes may be used to the maximum practicable extent to gain access to the electric service ground as shown in Figure 9. Note that the water pipe in Figure 9 is electrically continuous between electric and telecommunications bonds to the cold water pipe and it is used only as a portion of a bonding conductor and, therefore, does not have to be “acceptable” as a ground electrode but may be floating (isolated from ground by a plastic pipe section). ANSI/NFPA 70-1999, NEC ®, requires that metal piping be used as a bonding conductor in this manner only when the connectors to the pipe are within 1.5 m (5 ft) of where the pipe enters the premises. This is not the preferred installation. The RUS preferred installation has the telecommunications primary station protector grounded directly to an accessible location near the power grounding system. See paragraph (l) of this section. Figure 9 is as follows:

(n) Where the telecommunications premises system at a customer's access location is grounded to a separate electrode (of any type) this telecommunications grounding electrode must be bonded to the electric grounding system with a No. 6 AWG or larger copper insulated grounding conductor. Bonding of separate electrodes is a requirement of the ANSI/NFPA 70-1999, NEC ®.

(o) The NID, BET, or fused primary station protector pair size shall be selected for the number of lines anticipated within five years.

(p) When lightning damage is considered probable or customer access locations are remote from the borrower's headquarters, use of maximum duty gas tube primary station protectors incorporated in NIDs, BETs, or fused primary station protectors should be considered. (See RUS TE&CM 823, Electrical Protection by Use of Gas Tube Arresters). Copies of RUS TE&CM 823 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

(q) NIDs or BETs incorporating fuseless station protectors shall always be used in preference to fused station protectors or BETs incorporating fused protectors, when in the judgment of the RUS borrower or the engineer delegated by the RUS borrower, the requirements of ANSI/NFPA 70-1999, NEC ®, for fuseless station protectors can be met.

(r) A fuse link consisting of a copper conductor two gauges (AWG) finer (numerically higher) conductivity than the aerial service wire shall be provided between the cable and aerial service wire where NIDs or BETs incorporating fuseless station protectors are used. Thus for a 22 AWG drop, a fuse link of No. 24 AWG or finer copper wire shall be provided. If the cable circuit is No. 24 gauge or finer, the cable conductors serve as the fuse link for the 22 AWG aerial service wire and no separate fuse link is necessary. (Note: The fuse link or the facilities serving as the fuse link must be located between the telecommunications facilities that are exposed to possible power cross and the customer drop where there is no exposure to possible power cross.)

(s) RUS's buried plant practices require buried main line plant to be protected against power contacts to aerial plant extensions and aerial inserts by No. 24 AWG fuse links at every buried-aerial junction.

(t) In aerial cable plant, fuse links are usually provided by No. 24 AWG leads on filled terminal blocks regardless of the gauge of the cable conductors. This practice is acceptable if the ampacity of the aerial service wire is sufficiently higher than the fuse link's ampacity.

(u) The grounding and bonding of each NID, BET, or fused primary station protector shall be selected by consulting paragraphs (i) through (n) of this section. The “first choice” assembly unit shall be selected whenever the prevailing conditions make its use practicable. The NID, BET, or fused primary station protector assembly unit selected shall be installed in accordance with the appropriate construction drawing specified in RUS Bulletin 1753F-153 (RUS Form 515d), Specifications and Drawings for Service Installations at Customer Access Locations (Incorporated by reference at § 1755.97). Copies of RUS Bulletin 1753F-153 are available upon request from RUS/USDA, 1400 Independence Avenue, SW., STOP 1522, Washington, DC 20250-1522, FAX (202) 720-4120.

(v) The minimum size grounding conductor that can be used with a single NID; a group of NIDs; a multipair NID; fused protector; or BET shall be in accordance Table 5, as follows:

(w) Grounding conductor runs between the NID, BET, or fused station protector and the ground electrode shall conform to the following:

(1) The shortest, most direct route practicable shall be used;

(2) Sharp bends in the grounding conductor shall be avoided during installation;

(3) No splices shall be made in the grounding conductor;

(4) Grounding conductors shall not be fished through walls, under floors, or placed in bridle rings or any metal conduit unless the grounding conductor is bonded to the conductor at both ends of the metallic conduit;

(5) Grounding conductor runs from an outside mounted NID, BET, or fused station protector to an inside ground electrode shall use the same entrance as the station wire; and

(6) Grounding conductor runs from an outside mounted NID, BET, or fused station protector to an outside ground electrode at the building shall be attached to the exterior surface of the building or buried. If buried, the grounding conductor shall be either plowed or trenched to a minimum depth of 12 in. (300 mm). When trenched, the trenches shall be as close to the side of the building as practicable, backfilled, and tamped to restore the earth to its original condition.

(x) Telecommunications grounding connectors shall be RUS accepted or RUS technically accepted. Grounding and bonding conductors shall be made of copper. Where the grounding and bonding conductors must be connected to aluminum electric service grounding conductors, bimetal grounding connectors shall be used.

(y) Grounding conductor attachments shall conform to the following:

(1) Galvanized nails or clamps, or nickel-copper alloy staples shall be used for grounding conductor attachments in accordance with Table 6 in paragraph (y)(3) of this section;

(2) Grounding conductors, station or buried service wires in parallel runs may share the same fastening device when the device is specifically designed for two wires. See Table 6 in paragraph (y)(3) of this section for station wire and grounding conductor fasteners; and

(3) Grounding conductor fasteners shall be placed 12 to 18 in. (300 to 450 mm) apart on straight runs and 2 to 4 in. (50.8 to 100 mm) apart at corners and at bends. Table 6 is as follows:

Notes:

1. Screw dimensions are minimum. Where appropriate, either or both dimensions shall be increased. All wood screws for exterior use shall be stainless steel. All other exterior metal devices shall be stainless steel, zinc coated steel, silicon bronze, or corrosion resistant aluminum alloy.

2. Toggle bolt dimensions are minimum. Where appropriate, either or both dimensions shall be increased.

3. Wall screw anchors may be used in wall board, plaster or tile walls. Screws and nails in masonry shall be secured by means of expansions type anchors. Equivalent manual or machine-driven devices may be used. Where toggle bolts are specified, equivalent devices may be used.

4. Lead holes shall be drilled for screws, nails, and bridle rings in shingles and dropsiding.

5. Sheet metal screws shall be used except where toggle bolts are required. Where wood sheathing under sheet metal siding is encountered, the sheet metal may be drilled or punched and a wood screw used.

6. Machine-driven staples of nickel-copper composition may be used for exterior wiring.

7. Galvanized clamps and wiring nails may be used for exterior and interior wiring. Enameled clamps shall be used for interior wiring only. Where toggle bolts or equivalent devices require holes in the structure larger than the clamp being fastened, a suitable washer of sufficient size to cover the hole must be used under the clamp.

8. Double clamp may be used where two #22 AWG station wires, two #12 AWG grounding conductors, or one #22 AWG station wire and one #12 grounding conductor parallels one another.

9. For converting English units to Metric units use 1 in. = 25.4 mm.

(z) Grounding conductors shall be separated from non-telecommunications company wires in accordance with section 800-12(b) of ANSI/NFPA 70-1999, NEC ®.

(aa) Grounding conductors run through metal conduits shall be bonded to the conduit at each end. RUS accepted and RUS technically accepted pipe type ground clamps and grounding connectors shall be used for bonding.

(bb) Where NID, BET, or fused station protector assembly units require grounding conductor connections to pipe systems, the following apply:

(1) The connection shall be made to a cold water pipe of an operating water system;

(2) The connection point shall be preferably inside the building;

(3) Allow a minimum of 6 in. (152 mm) between the last fastener and the point where the grounding conductor first touches the water pipe;

(4) Leave 2 in. (50.8 mm) of slack in the grounding conductor to avoid breaking the conductor at the terminating point. Tape the grounding conductor to the pipe where possible to avoid movement. In no case, shall the grounding conductor be coiled or wrapped around the pipe;

(5) The pipe shall be cleaned with fine sand paper to make a good electrical connection. Care should be taken to avoid damaging the pipe while cleaning it;

(6) Attach the pipe grounding conductor connector to the cleaned area of pipe and tighten. Care shall be exercised to avoid deforming, crushing, or otherwise damaging the pipe. A simple continuity check with an ohmmeter between the connector and the pipe will indicate whether or not a good electrical contact has been made. Set the ohmmeter to “Rx1” scale to ensure that a low resistance contact is made;

(7) A warning tag shall be attached to the ground clamp with the following or equivalent statement: “Call the telecommunications company if this connector or grounding conductor is loose or must be removed;” and

(8) When the water pipe is used, the ANSI/NFPA 70-1999, NEC ®, requires that metal piping be used as a bonding conductor in this manner only when the connections to the pipe are within 5 ft (1.5 m) of where the pipe enters the premises.

(cc) Bonding conductors shall consist of either copper or tinned copper insulated wires of appropriate sizes.

(1) Bonding conductors shall be run and attached in the same manner as grounding conductors.

(2) Attaching and terminating devices for bonding conductors shall be adequate for the size of wire involved. The No. 6 AWG copper insulated conductor or larger shall not be terminated by bending it around a threaded stud.

(dd) Where NID, BET, or fused station protector assembly units require a driven ground rod the following shall apply to the ground rod installation:

(1) Locate the ground rod at least 1 ft (300 mm) from buildings, poles, trees and other obstruction;

(2) Ground rods shall not be installed within 6 ft (2 m) of electric service ground rods (Note: This minimum separation is provided to avoid mutual impedance effects of multiple grounding electrodes that will deleteriously degrade the effective impedance-to-earth if grounding electrodes are installed any closer than 6 ft (2 m) to one another. This requirement is included for cases where the telecommunications company is not allowed, for some reason, to observe the RUS preferred grounding method of attaching the primary protector grounding conductor directly to an accessible point on the building electric service grounding system. RUS believes that if the primary protector location can be sited within 6 ft (2 m) of the electric service ground rod then the electric service ground rod could be used as the preferred telecommunications grounding electrode and a separate telecommunications ground rod is unnecessary);

(3) A hole, 15 in. (350 mm) deep and 6 in. (150 mm) in diameter, shall be dug at the location where the ground rod is to be driven;

(4) Where “slip-on” type ground rod clamps are used instead of “clamp-around” type clamps, the ground rod clamps shall be placed onto the rod prior to driving the rod into the ground (Note there should be one clamp for the NID, BET, or fused station protector grounding conductor and one clamp for the conductor required to bond the telecommunications ground rod to the electric grounding system). However, the clamp shall not be tightened until the rod is completely driven. The end of the rod shall be placed in the bottom of the hole and the rod shall be aligned vertically adjacent to one wall of the hole prior to driving. The rod shall be driven until its tip is 12 in. (300 mm) below final grade. The grounding conductor shall then be attached, the clamp shall be tightened, and hole backfilled. Clamps employed in this manner shall be suitable for direct burial and shall be RUS accepted or RUS technically accepted; and

(5) Where rods are manually driven, a large number of blows from a light hammer (4 lbs (1.8 kg)) shall be used instead of heavy sledgehammer type blows. This should keep the rod from bending.

(ee) Terminations on fuseless primary station protectors incorporated in NIDs and on fused primary station protectors shall be as shown in Figures 10, 11, 12, and 13 of paragraph (ee)(1) of this section, Figure 14 of paragraph (ee)(4) of this section, and Figure 15 of paragraph (ee)(6) of this section. The inner jackets of buried service wires and outer jackets of cables used as service drops shall be extended into the NID or the fused primary station protector. A 10 in. (250 mm) length of each spare wire shall be left in NIDs or fused primary station protectors. The spare wires shall be coiled up neatly and stored in the NID or fused primary station protector housing.

(1) The shields of buried service wires may be connected to the ground binding post using RUS accepted or RUS technically accepted buried service shield bond connectors as shown in Figure 10 for NIDs and Figure 11 for fused primary station protectors. RUS accepted or RUS technically accepted buried service wire harness wires designed for customer access location installations may also be used for terminating buried service wire shields to the ground binding post of the NID as shown in Figure 12 and Figure 13 for fused primary station protectors. Figures 10 through 13 are as follows:

(2) On buried service drops and aerial service drops of more than 6 pairs using RUS accepted or RUS technically accepted cables, the shields shall be terminated with a RUS accepted or RUS technically accepted cable shield bonding connector and extended to the ground binding post of the NID, BET, or fused primary station protector with an RUS accepted or RUS technically accepted bonding harness wire. The installation of the shield bond connector and bonding harness wire shall be in accordance with the manufacturer's instructions.

(3) The shield and other conductors at the fuseless primary station protector incorporated in the NID shall be terminated as shown on Figure 14 in paragraph (ee)(4) of this section. The pronged or cupped washer shall be placed above the shield. The grounding conductor shall be placed around the post on top of the pronged or cupped washer. A flat washer shall be placed above the grounding conductor.

(4) The station wire signaling ground conductor, if required, shall be placed above the first flat washer and beneath the second flat washer as indicated in Figure 14 as follows:

(5) The shield and other conductors at the fused primary station protector shall be terminated as shown on Figure 15 in paragraph (ee)(6) of this section. The pronged or cupped washer shall be placed above the shield. The grounding conductor shall be placed around the post on top of the pronged or cupped washer. A flat washer shall be placed above the grounding conductor.

(6) The station wire signaling ground conductor, if required, shall be placed above the first flat washer and beneath the second flat washer as indicated in Figure 15 as follows:

(7) Indoor NIDs or BETs that are equipped with “Quick Connect” type terminals shall not have more than one wire connected per clip. No. 19 AWG copper and No. 18 AWG copper covered-steel reinforced aerial service wire conductors shall not be connected to quick connect terminals. Nonmetallic reinforced aerial service wire using No. 22 AWG copper conductors may be connected to the quick connect terminals.

(8) Tip and ring connections and other connections in multipair NIDs or BETs shall be as indicated in Figure 16 as follows:

(ff) System polarity and conductor identification shall be maintained in NIDs, BETs, or fused primary station protectors in accordance with construction drawings 815 and 815-1 contained in § 1755.510.

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

(a) Customer access location installations at mobile homes shall be treated the same whether the homes are mounted on permanent foundations or temporary foundations and shall be installed as specified in §§ 1755.500 through 1755.510. For the purpose of this section, mobile homes include manufactured homes, motor homes, truck campers, travel trailers, and all forms of recreational vehicles. Customer access location installations at mobile homes can be considerably different than customer access location installations at regular homes and borrowers shall be certain that the two types of installations are properly applied.

(b) The method of customer access location installation prescribed by the ANSI/NFPA 70-1999, NEC ® for a mobile home depends on how the electric power is installed at the mobile home and it can involve considerable judgment on the part of the telecommunications installer. The National Electrical Code ® and NEC ® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02269. The ANSI/NFPA 70-1999, NEC ®, is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from NFPA, 1 Batterymarch Park, P. O. Box 9101, Quincy, Massachusetts 02269-9101, telephone number 1 (800) 344-3555. Copies of ANSI/NFPA 70-1999, NEC ®, are available for inspection during normal business hours at RUS, room 2905, U.S. Department of Agriculture, 1400 Independence Avenue, SW., STOP 1598, Washington, DC 20250-1598, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. The ANSI/NFPA 70-1999, NEC ®, requires primary station protectors to be located where specific acceptable grounding electrodes exist. The ANSI/NFPA 70-1999, NEC ®, allows station protector installations to be at the location of the power meter or the electric disconnecting means apparatus serving the mobile home providing these electric facilities are installed in the manner specifically defined by the ANSI/NFPA 70-1999, NEC ®. The ANSI/NFPA 70-1999, NEC ®, requires the station protectors to be installed at the nearest of a number of other meticulously defined ANSI/NFPA 70-1999, NEC ®, acceptable electrodes where the protector cannot be installed at the power meter or the electric disconnecting means apparatus serving the mobile home. The provisions can be confusing.

(c) NIDs shall be installed at mobile homes as follows:

(1) Where the mobile home electric service equipment (power meter, etc.,) or the electric service disconnecting means associated with the mobile home is located within 35 ft (10.7 m) of the exterior wall of the mobile homes it serves, the NID shall be installed in accordance with Figure 17 as follows:

(2) Where the mobile home electric service equipment (power meter, etc.,) or the electric service disconnecting means associated with the mobile home is located more than 35 ft (10.7 m) from the exterior wall of the mobile homes it serves, the NID shall be installed in accordance with Figure 18 as follows:

(d) The service wire and station wire shall be terminated in the NID in accordance with Figure 19 in paragraph (e) of this section.

(e) Installation of the station wire and grounding conductor at the mobile home shall be in accordance with Figure 20. Figures 19 and 20 are as follows:

[66 FR 43317, Aug. 17, 2001, as amended at 69 FR 18803, Apr. 9, 2004]

(a) The construction and assembly unit drawings in this section shall be used by borrowers to assist the installer in making the customer access location installations.

(b) The asterisks appearing on the construction drawings indicate that the items are no longer listed in the RUS Informational Publication (IP) 344-2, “List of Materials Acceptable for Use on Telecommunications Systems of RUS Borrowers.” RUS IP 344-2 can be obtained from the Superintendent of Documents, P. O. Box 371954, Pittsburgh, PA 15250-7954, telephone number (202) 512-1800.

(c) Drawings BM50, BM83, 312-1, 501-1, 501-2, 503-2, 504, 505, 506, 507, 508-1, 510, 510-1, 510-2, 513, 815, 815-1, 958, and 962 are as follows:

[66 FR 43327, Aug. 17, 2001]

(a) General. (1) This section covers general requirements for a digital telephone central office switching system, which is fully electronic and controlled by stored program processors. A digital switching system transfers information which is digitally encoded from any input port to a temporarily addressed exit port. The information may enter the system in either analog or digital form and may or may not be converted to analog at the exit port depending on the facility beyond. The switching system shall operate properly as an integral part of the telephone network when connected to physical and carrier derived circuits meeting RUS specifications and other generally accepted telecommunications practices.

(2) The output of a digital-to-digital port shall be Pulse Code Modulation (PCM), encoded in eight-bit words using the mu-255 encoding law and D3 encoding format, and arranged to interface with a T1 span line.

(3) American National Standards Institute (ANSI) Standard S1.4-1983, Specification for Sound Level Meters, is incorporated by reference by RUS. This includes S1.4A-1985 that is also incorporated by reference. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies may be obtained from ANSI Inc., 11 West 42nd Street, 13th Floor, New York, NY 10036, telephone 212-642-4900. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(4) American Society for Testing Materials (ASTM) Specification B 33-91, Standard Specification for Tinned Soft or Annealed Copper Wire for Electrical Purposes, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies may be obtained from ASTM, 1916 Race Street, Philadelphia, PA, telephone 215-299-5400. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(5) Bell Communications Research (Bellcore) document SR-TSV-002275, BOC Notes on the LEC Networks—1990, March 1991, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan Part 51. Copies may be obtained from Bellcore Customer Service, 60 New England Avenue, Piscataway, NJ 08854, telephone 1-800-521-2673. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(6) Bellcore span-TSY-000508, Automatic Message Accounting, July 1987, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies may be obtained from Bellcore Customer Service, 60 New England Avenue, Piscataway, NJ 08854, telephone 1-800-521-2673. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(7) Federal Standard H28, Screw-Thread Standards for Federal Services, March 31, 1978, is incorporated by reference by RUS. This includes: Change Notice 1, Federal Standard, Screw-Thread Standards for Federal Services, May 28, 1986; Change Notice 2, Federal Standard, Screw-Thread Standards for Federal Services, January 20, 1989; and Change Notice 3, Federal Standard, Screw-Thread Standards for Federal Services, March 12, 1990. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies may be obtained from the General Services Administration, Specification Section, 490 East L'Enfant Plaza SW, Washington, DC 20407, telephone 202-755-0325. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(8) Institute of Electrical and Electronics Engineers (IEEE) Std 455-1985, IEEE Standard Test Procedure for Measuring Longitudinal Balance of Telephone Equipment Operating in the Voice Band, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies may be obtained from IEEE Service Center, 445 Hoes Lane, P. O. Box 1331, Piscataway, NJ 08854, telephone (201) 981-0060. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(9) Institute of Electrical and Electronics Engineers (IEEE) Std 730-1989, IEEE Standard for Software Quality Assurance Plans, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. Copies may be obtained from IEEE Service Center, 445 Hoes Lane, P. O. Box 1331, Piscataway, NJ 08854, telephone (201) 981-0060. Copies may be inspected during normal business hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(10) RUS Bulletin 345-50, PE-60, RUS Specification for Trunk Carrier Systems, September 1979, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552 (a) and 1 Cspan part 51. Copies may be obtained from the Rural Utilities Service, Administrative Services Division, room 0175-S, Washington, DC 20250. The bulletin may be inspected at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(11) RUS Bulletin 345-55, PE-61, Central Office Loop Extenders and Loop Extender Voice Frequency Repeater Combinations, December 1973, is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552 (a) and 1 Cspan part 51. Copies may be obtained from the Rural Utilities Service, Administrative Services Division, room 0175-S, Washington, DC 20250. The bulletin may be inspected at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(12) RUS Bulletin 345-87, PE-87, RUS Specification for Terminating (TIP) Cable, December 1983, is incorporated by reference RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552 (a) and 1 Cspan part 51. Copies may be obtained from the Rural Utilities Service, Administrative Services Division, room 0175-S, Washington, DC 20250. The bulletin may be inspected at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(b) Reliability. (1) Quality control and burn-in procedures shall be sufficient so the failure rate of printed circuit boards does not exceed an average of 1.0 percent per month of all equipped cards in the central office during the first three months after cutover, and an average of 0.5 percent per month of all equipped cards in the central office during any 6-month period thereafter. A failure is considered to be the failure of a component on the PC board which requires it to be repaired or replaced.

(2) The central office switching system shall be designed such that the expected individual line downtime does not exceed 30 minutes per year. This is the interval that the customer is out of service as a result of all failure types, excluding dispatch and travel time, i.e., hardware, software, and procedural errors.

(3) The central office switching system shall be designed such that there will be no more than 1 hour of total outages in 20 years, excluding dispatch and travel time for unattended offices.

(c) System type acceptance tests. (1) System type acceptance tests (general acceptance tests) are performed for the purpose of determining whether or not a type of switching system should be added or retained as an RUS accepted system. While general acceptance tests will be required on each system type, they will not be expected to cover every requirement in this section. However, any installation of a system provided in accordance with this section shall be capable of meeting any requirement in this section on a spot-check basis.

(2) A “completed call” test shall be made part of these system type acceptance tests. There shall be no more than two in 10,000 locally originating and incoming calls misdirected, unsuccessfully terminated, prematurely disconnected or otherwise failing as a result of equipment malfunction and/or equipment failures, or as a result of transients, noise or design deficiencies. This test shall be made with a load box with no less than 10 lines access and 10 subscriber numbers for completion, or equivalent, with no other traffic in the system. If there is a failure in the equipment during this test, the cause shall be repaired and the test restarted at zero calls.

(3) System type acceptance testing applies basically to factory type testing, and not to owner acceptance testing for individual installations. The overall installed and operating system shall also meet these requirements, except for unusual circumstances or where specifically excluded by this or other RUS requirements.

(d) Types of requirements. (1) Unless otherwise indicated, the requirements listed in this section are fixed requirements.

(2) Optional requirements are those which may not be needed for every office and are identifiable by a phrase such as, “when specified by the owner,” or, “as specified by the owner.”

(3) In some cases where an optional feature specified in paragraph (e) of this section will not be required by an owner, either now or in the future, a system which does not provide this feature will be considered to be in compliance with this section for the specific installation under consideration, but not in compliance with the entire section.

(4) The owner may request bids from any RUS accepted supplier whose system provides all the features which will be required for a specific installation.

(5) The Application Guide, RUS TE&CM 322, provides information about the economic and service factors involved in all optional features, as well as instructions for the completion of appendices A and B of this section.

(e) General requirements. (1) The equipment shall provide for terminating and automatically interconnecting subscriber lines and trunks in response to dial pulses (or pushbutton dialing signals, if specified) without the aid of an operator.

(2) Complete flexibility shall be provided for assigning any subscriber directory number to any central office line equipment by the use of internal programmed memory. Thus, any subscriber line and/or directory number may be moved to another terminal to distribute traffic loads, if the line equipment hardware is compatible with the service provided.

(3) The system shall be arranged to interface with interexchange carrier trunks and networks using single digit or multi-digit access codes. The system shall be equipped to handle at least 20-digit subscriber dialed numbers. All subscriber directory numbers in the office shall be seven-digit numbers.

(4) The network and the control equipment shall be comprised of solid-state and integrated circuitry components. Peripheral equipment shall be comprised of solid-state and integrated circuitry components as far as practical and consistent with the state-of-the-art and economics of the subject system.

(5) The basic switching system shall include the provision of software programming and necessary hardware, including memory, for optional custom calling services such as call waiting, call forwarding, three-way calling, and abbreviated dialing. It shall be possible to provide these services to any individual line (single-party) subscriber. The addition of these services shall not reduce the anticipated ultimate engineered line, trunk, and traffic capacity of the switching system as specified in appendix A of this section.

(6) The requirements in this specification apply only to single party lines. Although only single frequency ringing is required, other types may be requested in appendix A of this section.

(7) Provision shall be made for local automatic message accounting (LAMA), and for traffic service position system (TSPS) trunks, or equivalent, to the operator's office when required either initially or in the future.

(8) Tandem switching features shall be provided if specified in appendix A of this section.

(9) The system shall be arranged to serve a minimum of eight All Number Calling (ANC) office codes per office, with discrimination on terminating calls by trunk group, numbering plan, or programmed memory and class mark, if specified in appendix A of this section.

(10) Busy hour load handling capacity is an important feature when an office approaches capacity. The delays which may occur in call completion during busy hour periods may prove to be excessive in some system designs. Accordingly, each bidder shall provide, in appendix C of this section, data satisfactory to RUS regarding the busy hour load handling capacity and traffic delays of the system.

(11) Provision shall be made for hotel-motel arrangements, as required by the owner, to permit the operation of message registers at the subscriber's premises to record local outdial calls by guests (see Item 10.5, appendix A of this section).

(12) Provision shall be made to identify the calling line or incoming trunk on nuisance calls (see paragraph (g)(10) of this section for details).

(13) Full access from every subscriber line to every interoffice trunk shall be provided.

(14) Facilities shall be provided to implement service orders, make traffic studies, and perform switching and transmission tests by means of remote control devices if such operations are specified in Items 11.2 and 11.3 of appendix A of this section.

(15) Provision shall be made for the addition of facilities to record all subscriber originated calls based on dialed directory number, time of day, and duration of conversation. They shall be such that the additional equipment (if any is required) may be added to an in-service system without interruption of service and a minimum of equipment, wiring and software modifications.

(16) The system shall be capable of distributed switching operation where groups of subscriber lines can be remotely located from the central office. The remotely situated units are known as “Remote Switching Terminals” (RST's) (see paragraph (w) of this section). This does not eliminate the use of pair gain devices such as direct digitally connected concentrators, regular concentrators or subscriber carrier equipment, where specifically ordered by the owner and its engineer.

(17) The switching system shall have means to synchronize its clock with switches above it in the network hierarchy, when specified by the owner in item 3, appendix A of this section (see paragraph (j) of this section).

(18) Consistent with system arrangements and ease of maintenance, space shall be provided on the floor plan for an orderly layout of future equipment bays that will be required for anticipated traffic when the office reaches its ultimate size. Readily accessible terminals shall be provided for connection to interbay and frame cables to future bays. All cables, interbay and intrabay (excluding power), if technically feasible, shall be terminated at both ends by use of connectors.

(19) When specified in appendix A of this section, the system shall be capable of processing emergency calls to a 911 service bureau connected either by a group of one-way 911 lines or a trunk group.

(i) It shall be possible to reach the service bureau by dialing 911, 1 + 911, or a 7-digit number.

(ii) The system shall select an idle 911 line or trunk.

(iii) The system shall provide usual ringing and ringback signal until the called 911 line answers.

(iv) If the calling line goes on-hook first, the system shall hold the connection from the called 911 line and return steady low tone to the service bureau. The system shall then begin a 45-minute timeout, after which the calling line is disconnected and an alarm message is printed on a TTY. If the calling line goes off-hook before timeout, the system shall reestablish the conversation path.

(v) If the calling line does not disconnect, the service bureau attendant shall have the ability to force a disconnect of the established connection with the calling party.

(vi) When the 911 call is answered, the equipment shall be arranged so that coin lines are not charged for the call. Similarly, if some form of local call charging is used, there shall be no charge for the 911 call.

(vii) If the 911 service bureau is holding a calling line, it shall be possible for the 911 line to cause the equipment to ring back the calling line. This is done by providing a flash of on-hook signal from the 911 line lasting from 200 to 1,100 milliseconds. The signal to the calling line shall be ringing current if the line is on-hook, or receiver off-hook (ROH) tone if the line is off-hook.

(viii) Calls shall not be originated from the service bureau via the dedicated 911 lines. If an attempt is made to originate a call, it shall receive reorder tone. After 6 minutes, the system shall print an alarm message.

(ix) If 911 calls pass through intermediate switching, the forced-hold control, emergency ringback, and calling line status monitoring capabilities are lost.

(f) Line circuit requirements—(1) General. (i) The range of direct current (dc) resistances of subscriber loops, measured from the main frame in the central office and including the telephone set shall be at least 0-1900 ohms without loop extension and 1900-3600 ohms with loop extenders, or equivalent. The range when using extension equipment may be significantly reduced for straight line ringers. These limits apply under maximum adverse environmental and manufacturing variation tolerance conditions. Central office voltage shall be stabilized at a value necessary to provide at least a nominal 21 milliamperes current with a nontreated loop of at least 1900 ohms. Minimum loop insulation resistance without loop extenders shall be 25,000 ohms between conductors or from either conductor or both conductors in parallel to ground. Loop insulation resistance for loop extension devices may be 100,000 ohms minimum between conductors or from either conductor or both conductors in parallel to ground.

(ii) In addition to operating on nonloaded cable pairs and subscriber carrier, the equipment shall function properly with D-66 and H-88 loaded cable pairs, including any provisions the equipment must control for the purposes of proper transmission.

(2) Dialing—(i) Subscriber dial speed. The line equipment and central office equipment (COE) in tandem shall operate satisfactorily when used with subscriber dials having a speed of operation between eight and twelve impulses per second and a break period of 55 to 65 percent of the total impulse period.

(ii) Subscriber dial interdigital time. The line equipment and central office equipment shall operate satisfactorily with subscriber rotary dial interdigital times of 200 milliseconds minimum, and with pushbutton dialing interdigital times of 50 milliseconds minimum.

(iii) Subscriber line pushbutton dialing frequencies. (A) The frequency pairs assigned for pushbutton dialing shall be as follows, with an allowable variation of ±1.5 percent:

(B) The receiver shall comply with the operating parameters of the dual-tone multifrequency (DTMF) central office receiver as described in section 6 of Bell Communications Research (Bellcore) document SR-TSV-002275, BOC Notes on the LEC Networks—1990.

(3) Impedance. For the purpose of this section, the input impedance of all subscriber loops served by the equipment is arbitrarily considered to be 900 ohms at voice frequencies.

(4) Lockout. (i) All line circuits shall be arranged for line lockout. When a permanent condition occurs prior to placing a line into lockout, a timed low level warning followed by a timed high level receiver off-hook (ROH) tone (see paragraph (i)(2)(xi) of this section) or a howler circuit (see paragraph (o)(2)(iii)(C) of this section) shall be applied to the line.

(ii) The line on lockout shall be reconnected automatically to the central office when the permanent off-hook condition is cleared.

(5) Pay stations. Pay stations may be prepay, or semi-postpay, as specified by the owner.

(6) Loop extension. (i) The number of lines which exceed 1900 ohms will be specified by the owner. When requested by the owner, the bidder shall furnish equipment to guarantee satisfactory operation of all lines.

(ii) Working limits for subscriber lines with loop extenders are covered in RUS Bulletin 345-55, PE-61, Central Office Loop Extenders and Loop Extender Voice Frequency Repeater Combinations.

(iii) Ringing from RUS accepted loop extenders, or their equivalent, shall be cut off from the called line when the handset at the called station is removed during the ringing or the silent interval.

(7) Private branch exchange (PBX) lines. PBX trunk hunting shall be available. It will not be necessary to segregate PBX lines to certain line groups.

(8) Quantity. A sufficient number of terminations shall be provided, in addition to the quantity specified by the owner for subscriber line service, to meet the requirements of the system for equipment testing, alarm checking, tone transfer, loop around test and other features.

(9) Types. There shall be provisions for types of lines such as ground start, loop start, regular subscriber, pay stations, etc.

(g) Intraoffice switching requirements. (1) The switching system shall:

(i) Provide dial tone in response to origination of a call by a subscriber, except on special lines where the application of dial tone is not applicable, such as manual and hot lines;

(ii) Remove dial tone immediately after the first digit has been dialed;

(iii) Recognize the class of service of the calling subscriber;

(iv) Register the digits dialed by the calling subscriber where the rotary dial or pushbutton dialing characteristics and the minimum interdigital times are as specified;

(v) Perform the necessary translation functions when the required number of digits have been registered, and select a channel to a proper outgoing trunk, if one is available, to the designated interexchange carrier;

(vi) Provide a transmission path from the calling subscriber line to the selected trunk, if an idle one is found;

(vii) Provide for more than one alternate route to the desired destination when specified by the owner, select an idle outgoing trunk in the first or second choice alternate route trunk group, if all trunks in the higher choice groups are busy, and provide a reorder signal (see paragraph (i)(2)(iv) of this section) to the subscriber if no trunks are available in the last choice alternate route;

(viii) Translate the proper part of the registered incoming routing data on tandem calls into an identification of an outgoing trunk group, select an idle trunk in that group, initiate the connection of the incoming trunk to the outgoing trunk, set the trunks in the proper configuration for tandem operation, and transmit information as required to permit completion to the desired destination in the distant office;

(ix) Transmit the proper stored information over the selected trunk to permit completion of outgoing calls to the desired destination by the distant office or offices, and provide multifrequency (MF) outpulsing when specified;

(x) Register all the digital information on calls incoming from a distant office, when dial or MF pulsing characteristics and interdigital times are as specified;

(xi) Translate internally a registered directory number into line equipment location, ringing code and terminating class (such as “PBX hunting”) on incoming or intraoffice calls;

(xii) Test the called line for a busy condition;

(xiii) Connect the incoming trunk or locally originated call to the called line if the called line is idle;

(xiv) Permit any type of ringing voltage available in the central office to be associated with any Subscriber Directory Number (SDN), cause the proper type of ringing voltage to be connected to the called line, and remove ringing from the line upon answer whether in the ringing or silent period; and

(xv) Test and monitor the switching system continually during periods of low traffic using the maintenance and diagnostic subsystem.

(2) The switching system shall offer at least the following originating and terminating class-of-service indications on a per-line basis to subscribers, as specified by the owner:

(i) Flat rate individual line, bridged ringing;

(ii) Flat rate PBX and trunk hunting numbers, bridged ringing;

(iii) Pay station;

(iv) Message rate subscriber line;

(v) Wide Area Telephone Service (WATS);

(vi) Extended Area Service (EAS);

(vii) Data service;

(viii) Hotel-Motel capability;

(ix) Denied originating;

(x) Denied terminating;

(xi) Custom calling features;

(xii) Special interexchange carrier accesses; and

(xiii) Presubscription to designated interexchange carrier.

(3) The switching system shall provide PBX hunting.

(i) At least one trunk hunting group in each 100 SDN's equipped shall be provided. More may be provided as specified by the owner.

(ii) PBX groups shall be of a reasonable size commensurate with the ultimate size of the switching system.

(iii) Any available SDN may be used for PBX trunk hunting.

(iv) Each PBX group shall have the capability of being assigned one or more nonhunting SDN's for night service.

(v) If the called line is a PBX hunting line, the switching system shall test all assigned lines in the hunting group for a busy condition.

(vi) If the called PBX group is busy, line busy tone, as specified in paragraph (i)(2)(iii) of this section, shall be returned to the originating end of the connection.

(4) The switching system shall provide pay stations which may be prepay or semi-postpay. The system shall be arranged so that an operator and emergency service (911) may be reached from prepay or semi-postpay coin lines without the use of a coin, when the proper pay station equipment is provided.

(5) To meet dialing requirements, the switching system shall:

(i) Initiate the line lockout function after a delay, as specified in paragraph (r)(3) of this section, if dial or pushbutton dialing pulses are not received after initiation of a call, preferably routing the subscriber line to a holding circuit for tones and then automatically to lockout;

(ii) Connect 120 interruptions per minute (IPM) paths busy tone, recorded message, or other distinctive tone to the calling subscriber if an interval longer than that specified in paragraph (r)(4) of this section elapses between dialed digits;

(iii) Register the standard tone calling signals received from a subscriber station arranged for pushbutton dialing if specified by the owner, provide arrangements to function properly with 12-button pushbutton dialing sets, and return a reorder signal to the subscriber upon receipt of signal from the 11th or 12th buttons if neither of these buttons is assigned functions; and

(iv) Connect the incoming trunk to the digit register equipment within 120 milliseconds after seizure where direct dialing is received on calls from a distant office, cancel the bid for a register, and return reorder tone to the calling end if dial pulses are received before a register is attached.

(6) The switching system shall provide for appropriate circuit usage.

(i) To avoid inefficient utilization of the switching network, that portion of the common equipment that establishes the connection on intramachine calls shall not require more than 500 milliseconds, exclusive of ringing and ring trip, to complete its function under no-delay conditions.

(ii) The switching system shall provide for duplication in a load sharing or redundant configuration any circuit elements or components, the failure of which would reduce the grade of service of 100 or more lines by more than 25 percent of the traffic carrying capacity.

(iii) The switching system shall ensure that failure of access to a high choice circuit will not prevent subsequent calls from being served by lower choice circuits, wherever possible.

(iv) Where only two circuits of a type are provided, circuits shall be designed so that failure of one circuit will not permanently block any portion of the system for the duration of the failure.

(v) Where more than two circuits of a type are provided, successive usages should be on a rotational or random basis rather than the step-up selection with the possible exception of a last choice trunk.

(vi) The system shall be designed so that, in the event of a network failure, the system shall immediately or simultaneously use a redundant portion of the network to complete the call.

(7) The switching system shall provide busy verification facilities with the method of access specified by the owner.

(i) Only an operator or a switchman shall be able to override a busy line condition.

(ii) If the called line is busy, off-hook supervision shall be given the operator or switchman.

(iii) The responsibility of restricting subscribers in distant offices from having access to busy verification shall be on the distant office personnel when the toll trunks are used for both toll connecting and verification traffic.

(iv) When a verification code is used, all digits of the code must be dialed before cut-through to the called line can be accomplished.

(8) The switching system shall provide intercept facilities.

(i) All unused numbering plan area codes, home numbering plan area office codes, service codes and subscriber directory numbers (SDN's) shall be routed to intercept. All intercept administration shall be by changes in memory administrable by telephone company personnel. Maximum machine time to place a subscriber on intercept shall be 15 seconds.

(ii) Unequipped SDN's intercept shall be effective if the processor memory does not have information concerning the SDN in question.

(iii) The intercept equipment shall be arranged so that specific SDN's can be routed to a separate intercept circuit for changed numbers.

(iv) When an intercept call is answered, either by an operator or by a recorded announcement, an off-hook or charge supervision signal shall not be returned, even momentarily, to the originating end.

(v) When intercepting service is to be handled over the regular interoffice toll trunks, a distinctive identifying tone shall be transmitted when the operator answers. This tone shall be of the frequency and duration specified in paragraph (i)(2)(x) of this section.

(9) The switching system shall provide nuisance call trap facilities which, when activated, provide a permanent record of the calling and called numbers complete with date and time of day. Where the call originates over an interoffice trunk, the actual trunk number shall be recorded. There shall be provision for the called subscriber to hold the connection and for the positive trace of the call from origination to termination within the office.

(10) The switching system shall follow appropriate release procedures.

(i) The office shall be arranged so a connection to a terminating channel other than assistance operator shall be released under control of the calling party so that the channel can be reseized, unless the call is to emergency 911 service or other termination arranged for called party control.

(ii) If the called party disconnects first, the channel used in the originally established connection shall be held until the calling party disconnects or until the timing interval specified in paragraph (r)(7) of this section has elapsed. This feature shall not interfere with the normal operation of calls to intercept, fire alarm, or other special services.

(11) The switching system shall provide line load control facilities, when specified by the owner, to give preference for originating service to a limited group of subscribers during emergencies.

(i) These facilities may be activated manually by input-output (I/O) device or automatically after a manual setting of a key (or equivalent) to put line load control into effect, as determined by the bidder. The automatic procedure is preferable.

(ii) Procedures shall be established to avoid the unauthorized use of the line load control facilities.

(iii) Where automatic activation is provided, service may be provided to small groups of nonemergency subscribers on limited grade of service whenever the office load becomes low enough to permit this to be done safely.

(h) Interoffice trunk circuit requirements—(1) General. (i) The bidder shall supply, as requested by the owner, solid-state technology type trunk and signaling circuits of any of the types described in RUS TE&CM 319, Interoffice Trunking and Signaling, or, with the approval of RUS, any other more recent and desirable types not as yet covered in the manual. For dc signaling, the duplex (DX) and loop types of signaling are preferred.

(ii) Trunks shall not be directly driven from the subscriber's dial on outward calls.

(iii) In order to reduce the spares inventory and minimize incidence of improper maintenance replacement of circuit assemblies, the types of trunk circuits shall be kept to a minimum. Variation in assemblies should be mainly limited to variation in signaling modes.

(iv) Trunk circuits which connect with carrier or 4-wire transmission facilities shall be arranged for 4-wire transmission to avoid an intermediate 2-wire interface between a 4-wire switching system and trunk facilities.

(2) Quantity. Trunk quantities shall be as specified in appendix A of this section. Sufficient space shall be provided for an orderly layout of trunks. Trunks of a certain type going to the same destination may be grouped together on the original installation.

(3) Requirements for interoffice connections. (i) When operator trunks are used in common for both coin and noncoin lines, they shall be arranged to provide an indication to the operator by means of a visual signal or tone when calls are from pay stations. When a tone is used, it shall be of the type specified in paragraph (i)(2)(v) of this section and shall be connected to be heard only by the operator upon answer. It shall be possible to repeat the tone signal.

(ii) There are no requirements for trunks arranged for manual re-ring by a toll operator, either with the receiver on or off the hook, except to coin stations with the receiver on the hook.

(iii) On calls from subscribers to the assistance operator, the release of the connection shall be under control of the last party to disconnect. An exception is operator control of disconnect that is used on outgoing trunks to a TSP/TSPS system.

(iv) On calls originated by an operator, the release of the connection shall be under control of the operator.

(v) Where trunks with E and M lead signaling are used, the trunk circuits for Type I signaling shall be arranged to place ground on the M lead during the on-hook condition and battery on the M lead in the off-hook condition. For E and M Type II, only a make contact between the MA and MB lead will be required. In either type, current limiting shall be provided in the E lead of the trunk circuit itself, as required for proper operation. It shall be assumed that connection equipment in the form of trunk carrier, multiplex, or associated signaling apparatus furnishes only a contact closure to ground (Type I) or to a signal ground lead (Type II) for an off-hook condition on the E lead.

(vi) Where answer supervision is used to determine the initiation of the charging interval for a call, such answer supervision shall not be effective for charging until after the elapse of the timing interval listed in paragraph (r)(5) of this section.

(vii) When necessary, provision shall be made for reception of start and stop dial signals on toll trunk equipment.

(viii) When trunks arranged for automatic message accounting (AMA), toll ticketing, or centralized automatic message accounting (CAMA) are specified by the owner, these trunks shall provide the pertinent features described in paragraph (k) of this section applicable to such functions.

(4) Requirements for direct digital connections. (i) Interface units which will permit direct digital connection to other digital switches, channel banks and remote line and/or trunk circuits over digital facilities shall be provided when specified by the owner. The digital transmission system shall be compatible with T1 type span lines using a DS1 interface and other digital interfaces that may be specified by the owner. The RUS specification for the span line equipment is Bulletin 345-50, PE-60, RUS Specification for Trunk Carrier Systems.

(ii) Each interface circuit shall connect 24 voice channels to the switching system from a 1.544 megabit per second DS1 bit stream. The DS1 bit stream entering or exiting the system shall be in the D3 format and the voice signals shall be encoded in 8 bit mu-255 PCM. The format and processing of the bit stream must be compatible with characteristics of the D3 channel bank such as alarm and maintenance characteristics. Loss of receive signal (DS1) shall be detected and the equivalent of a carrier group alarm shall be executed in 2.5 ±0.5 seconds. Loss of synchronization shall be detected by slips, timing jitter, and wander in accordance with industry standards.

(iii) Signaling shall be by means of MF or dial pulse (DP) and the system which is inherent in the A and B bits of the D3 format. In the case where they are not used for signaling, the A and B bits shall be used only for normal voice and data transmission.

(i) Tone requirements—(1) General. Tones shall be provided to indicate the progress of a call through the office. Tone generators should be an integral part of the switching systems. The tones should be introduced digitally by the application of the appropriate bit stream to the line or trunk circuit via the digital switching network. The necessary precautions shall be made to ensure tone sources automatically if the primary sources fail.

(2) Tone specifications. (i) Dial tone shall consist of 350 Hz plus 440 Hz at a composite level of −10 dBm0 which equates to −13 dBm0 per frequency. This is the precise tone suitable for use with pushbutton dialing.

(ii) Low tone shall consist of 480 Hz plus 620 Hz at a composite level of −21 dBm0 which equates to −24 dBm0 per frequency.

(iii) Line busy tone shall be low tone interrupted at 60 IPM, with tone on 0.5 seconds and off 0.5 seconds.

(iv) Reorder, all paths busy, and no circuit tone shall be low tone interrupted at 120 IPM, with tone on 0.25 seconds and off 0.25 seconds.

(v) Identifying tone on calls from coin lines shall be uninterrupted low tone.

(vi) High tone shall consist of 480 Hz at −17 dBm0.

(vii) Audible ringback tone shall consist of 440 plus 480 Hz at a composite level of −16 dBm0 which equates to −19 dBm0 per frequency.

(viii) The call progress tones listed in this section are described in Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks—1990, section 6. The 350, 440, 480, and 620 Hz tones shall be held at ±0.5 percent frequency tolerance and ±3 dB amplitude variation. The amplitude levels specified are to be measured at the main distributing frame, excluding cable loss.

(ix) Distinctive tone, when required for alarm calls, or other features, shall consist of high tone interrupted at 200 IPM with tone on 150 ms and off 150 ms.

(x) Identifying tone on intercepted calls shall consist of uninterrupted high tone impressed on the trunk circuit 300 to 600 milliseconds following the operator's answer of intercepted calls.

(xi) An ROH circuit shall have output tones which do not interfere with the pushbutton or multifrequency signaling tones. The ROH tone may be introduced digitally internal to the system near the overload level of + 3 dBm0. No power adjustment will be required. The frequency of the output shall be distinctive and urgent in order to attract the subscriber's attention to an off-hook situation. (Warning: In order to determine the signal level, a frequency selective voltmeter must be used to determine the level of each signal component and mathematical power addition used to combine these measurements into a single level value.)

(xii) During application of tones, office longitudinal balance shall be maintained within 15 dB of that specified in paragraph (q)(8) of this section.

(j) System clock. (1) The central office clock and network synchronization system shall have the ability to be synchronized with external clocks for network synchronization, including detection of slips, timing, jitter and wander, in a digital-to-digital environment or operate initially in an independent network (refer to Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks—1990, section 11).

(2) The end office central office system clock shall be a Stratum 3 clock with:

(i) A minimum long-term accuracy of ±4.6 × 10−6 (±7 Hz @ 1.544 MHz);

(ii) A minimum stability of 3.7 × 10−7/day upon loss of all frequency references; and

(iii) A “Pull-In Range” for the capability of synchronizing to a clock with accuracy of ±4.6 × 10 −6.

(3) The access tandem central office system clock shall be a Stratum 2 clock with:

(i) A minimum long-term accuracy of ±1.6 × 10−8 (±0.025 Hz @ 1.544 MHz);

(ii) A minimum stability of 1 × 10−10/day upon loss of all frequency references; and

(iii) A “Pull-In Range” for the capability of synchronization to a clock with accuracy of ±1.6 × 10−8.

(k) Switched access service arrangements—(1) General. The equipment shall be capable of providing Feature Group A, Feature Group B, Feature Group C, and Feature Group D switched access service arrangements, as described in Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks—1990, section 6 and section 15, including arrangements for automatic number identification (ANI).

(2) Operation. (i) All equipment shall be arranged for Feature Group A (Line Side Connection).

(ii) All equipment shall be arranged for Feature Group B given that appendix A of this section requires the equipment of the necessary trunks (Trunk Side Connection).

(iii) The equipment shall be arranged for Feature Group C on the trunk groups specified in appendix A of this section. Even though appendix A of this section specifies Feature Group D or some other trunk group, it shall be possible through software commands available to the owner to use Feature Group C signaling protocols on a trunk group basis until such time that the trunk group in question converts to Feature Group D signaling protocols.

(iv) The equipment shall be arranged for Feature Group D on the trunk groups specified in appendix A of this section.

(v) Calls originating from coin lines toward switched access service shall be arranged either to provide signaling protocols for TSPS, or in the absence of TSPS-type service, such calls shall be blocked.

(vi) The equipment shall be arranged for forwarding routing information, calling party identification, and called party numbers in the proper feature group protocols, by trunk group as specified in appendix A of this section.

(vii) The equipment shall be arranged for AMA data collection as specified in appendix A of this section by trunk group. Unless otherwise specified by the owner, the equipment shall be arranged to collect the billing data in the Bellcore AMA format as described in Bellcore document span-TSY-000508, Automatic Message Accounting.

(viii) If specified in Item 9.4, appendix A of this section, the equipment shall be arranged to store the billing data in a pollable system. If specified in Item 9.5, appendix A of this section, equipment shall be furnished to poll the pollable systems associated with the contract.

(l) Fusing and protection requirements—(1) General. (i) The equipment shall be completely wired and equipped with fuses, trouble signals, and arranged for printout of fault conditions, with all associated equipment for the wired capacity of the frames or cabinets provided.

(ii) Design precautions shall be taken to prevent the possibility of equipment damage arising from the insertion of an electronic package into the wrong connector, the removal of a package from any connector, or the improper insertion of the correct card in its connector.

(2) Fuses. Fuses and circuit breakers shall be of an alarm and indicator type, except where the fuses or breaker location is indicated on the alarm printout. Their rating shall be designated by numerals or color code on the fuse panel, where feasible.

(3) Components. (i) Insofar as possible, all components shall be capable of being continuously energized at rated voltage without injurious results. Insofar as possible, design precautions shall be taken to prevent damage to other equipment and components when a particular component fails.

(ii) Printed circuit boards or similar equipment employing electronic components shall be self-protecting against external grounds applied to the connector terminals, where feasible. Board components and coatings applied to finished products shall be of such material or treated so they will not support combustion.

(iii) Every precaution shall be taken to protect electrostatically sensitive components from damage during handling. This shall include written instructions and recommendations (see Item 6.1,h of appendix C of this section).

(m) Switching network requirements—(1) The network. (i) All networks shall be comprised of solid-state components.

(ii) The switching network shall employ time division digital switching and be compatible for connection to D3 type PCM channel banks without conversion to analog.

(iii) Equipment shall be available as required to connect analog lines and trunks, analog or digital service circuits, digital carriers to RST's, D3 channel banks or other digital switching units.

(2) Network quantity. Where the number of stages in the switching network and their control varies with the capacity of the system, sufficient equipment and wiring shall be supplied initially in order that there will be no service interruptions when additions are made up to the ultimate capacity as specified in appendix A of this section. This does not imply the necessity of supplying empty cabinets unless this is the only way the necessary wiring can be accomplished.

(n) Stored program control (SPC) equipment requirements. (1) The system shall provide redundancy in call processing such that the failure of a call processing unit does not degrade the call processing capabilities of the switching system nor result in the loss of established calls.

(2) Programs shall be modular, flexible and structured. In the interest of more dependable and more easily read programs, it is desirable to use a language which is more person-oriented leaving the detailed machine-oriented problems to a compiler program. Quality assurance of all software programs shall be in accordance with IEEE Std 730-1989, IEEE Standard for Software Quality Assurance Plans, or equivalent.

(3) The office administration program shall have checks within it to prevent failure due to erroneous or inconsistent input data. It shall safeguard against the possibility of upsetting machine performance with improper instructions or information. In addition, modular structure shall allow the use of a variety of human-engineered service order formats. Service changes may be performed remotely if so desired. Average machine time for service change shall be 15 seconds or less. Service changes shall not be registered in permanent memory until verified. The access to the service change shall not have access to generic program.

(4) The switching system shall be able to offer, by request, at least the following printouts of its routine stored data for administrative purposes:

(i) A list of all assigned directory numbers, in numerical order, with their assigned class of service and line terminal numbers;

(ii) A list of all directory numbers, in numerical order, associated with a class of service;

(iii) A list of all unassigned line terminals;

(iv) Traffic data in proper form for separation studies in accordance with the revenue separations procedures current at the time of the contract;

(v) All lines on lockout;

(vi) All lines assigned to intercept;

(vii) All available (unassigned) directory numbers in the working thousands group; and

(viii) A list of equipment busied out for maintenance.

(5) The printouts in paragraph (n)(4) of this section may be delayed to times of light traffic.

(6) Maintenance diagnostics shall be performed by a fault recognition system utilizing both software and hardware, each being used where they are most effective for maintenance and reliability. In the economic interests of providing early and efficient fault detection and accurate pinpointing of faulty areas, it is desirable to have a comprehensive person-machine interface supported by extensive automatic fault detection and analysis, involving diagnostic software for fault resolution and automatic recovery mechanisms to maintain continuous service. Maintenance messages may be channeled to a remote maintenance center if so desired.

(7) Information in memory, having no requirement for changes to be introduced in the maintenance or operation of the system, may be stored in memory devices such as programmable read-only memory (PROM) or other devices that cannot be reprogrammed in the field.

(o) Maintenance facilities—(1) Alarm features, including alarm sending. (i) The equipment shall be arranged to provide audible and visual alarms indicating fuse operation or other circuit malfunctions resulting from component failure, crosses or open wiring, or any other conditions affecting service which can be detected economically.

(ii) The alarms shall be classified in accordance with their effect on the system.

(A) Catastrophic alarms demand immediate attention and require notification of the highest level of supervisory personnel. Conditions such as loss of service, loss of one or more remote line switches or line concentrators connected through Direct Digital Interface, loss of network control, and loss of computer program in all processors shall produce catastrophic alarms.

(B) Major alarms demand rapid action. Conditions such as loss of one or more groups of subscribers or trunk ports, blown fuses for common groups of channels, loss of control to groups of channels, failure of one or both redundant units, and total loss of battery charging current for more than 15 minutes shall produce major alarms.

(C) Minor alarms indicate nonemergency conditions which cause degraded service or fault conditions which causes the system to operate within less-than-optimum performance. Conditions discovered in automatic routining which have not shown in the operation of the equipment but require attention and cumulative line lockout (level adjustable) are examples of minor alarm conditions.

(iii) When the office is arranged for unattended operation, facilities shall be provided for extending the alarm indications to an attended point.

(iv) When the use of a separate outside plant facility for alarm sending is specified, the nature of the alarm may be indicated to the distant point by machine printout or other display device.

(v) When alarm sending is accomplished over a regular operator office trunk, the operator shall be apprised that the call is an alarm indication by a distinctive tone, as specified by the owner in appendix A of this section. It shall be possible for the operator to determine at any time the presence of a trouble condition by dialing a number set aside for that purpose. This number shall also be accessible from lines classmarked for this feature.

(vi) When the alarm sending circuit seizes an interoffice operator trunk, the operator must dial the alarm checking code over another trunk before the first trunk can be released except where the alarm condition has disappeared first.

(vii) The alarm sending circuit shall have access to two or more trunks if the trunks are used for subscriber traffic.

(viii) An alarm indication of higher priority shall supersede an original alarm indication and reseize an interoffice operator trunk.

(ix) In any group of offices purchased under one contract, the same codes shall be used in each office for alarm checking and test.

(x) When the alarm checking number is dialed, the alarm indications received shall be as follows:

(A) Catastrophic alarm—No tone.

(B) Major alarm—Continuous busy tone 60 IPM, unless alarm is overridden.

(C) Minor alarm—Continuous 1-ring code ringback tone, unless alarm is overridden.

(D) No trouble—Continuous 2-ring code ringback tone, unless alarm is overridden.

(xi) Audible and visual local alarms and transmitted alarms shall be provided as follows:

(xii) The central office alarm circuits shall be arranged to provide optional wiring to transmit either a minor alarm or a major alarm and a printout to accommodate various types of trunk and subscriber carrier systems, microwave, mobile radio, other transmission systems, and environmental protection systems with different priorities when a set of contacts is closed in the equipment of such systems and the alarm checking code is dialed. The alarm relay shall be furnished by the supplier of the carrier multiplex and/or mobile radio equipment. The option or options shall be specified by the owner.

(2) Trouble location and test. (i) Equipment. (A) A maintenance center shall be provided with a fault recorder (printer and/or display) for troubles. Here, system and sub-system visual trouble indications are shown for maintenance aid.

(B) The fault recorder shall provide a permanent or semi-permanent record of the circuit elements involved whenever a trouble is encountered. It shall be arranged to recognize an existing fault condition and not cause multiple printouts of the same fault, except during test routine.

(ii) Maintenance system. (A) The maintenance system shall monitor and maintain the system operation without interruption of call processing, except for major failures.

(B) The maintenance system shall provide both specialized maintenance hardware circuits and an extensive software package to enable maintenance to determine trouble to an individual card or functional group of cards.

(C) Maintenance programs may be both on-line and off-line. On-line maintenance programs are activated by system errors and shall be scheduled to execute call tests during low traffic periods and periodic hardware tests at specific time intervals. Programs shall provide diagnostic tools for the maintenance personnel and be initiated by them.

(D) Scheduled periodic hardware tests shall automatically detect faults and alert maintenance personnel via alarm or appropriate input/output device(s) at local and/or remote locations.

(E) Facilities shall be provided so that test calls can be set up using pre-selected items of switching equipment.

(F) The maintenance personnel shall be able to make tests to determine if every trunk and every item of switching equipment are functioning properly. Also, it shall be possible to make each trunk and each SPC equipment, or part thereof, busy to service calls. Where possible, equipment which is made busy to service calls shall still be accessible for test calls.

(iii) Outside plant and subscriber stations. (A) A subscriber loop test set or equivalent shall be provided either as a separate set or as a part of the maintenance center, as specified in item 11.2 of appendix A of this section. This circuit shall include a high resistance volt-ohm meter, wiring to tip and ring terminals to permit a portable wheatstone bridge to be used, an operator's telephone circuit, a dial circuit (and pushbutton dialing keys, if specified), outgoing trunks to dial equipment for access to lines under test without use of the main distributing frame (MDF) test shoe and the necessary test keys. No dry cell batteries shall be accepted for test potentials. Circuits shall be designed so that alternating current (ac) induction on the line will have no effect on dc measurements. All functions shall be under control of lever or pushbutton keys. As a minimum the test system shall:

(1) Test for bridged foreign electromotive force (EMF);

(2) Test for regular line battery;

(3) Test for booster battery voltage and polarity using the test shoe;

(4) Test for open circuits, short, tip ground, and ring ground;

(5) Test for tip or ring negative potential;

(6) Test for capacitance of a subscriber's line;

(7) Supply talking battery to the line with and without booster battery;

(8) Ring the subscriber through the test access circuit or through a test shoe;

(9) Test in and out of the central office; and

(10) Supply a reverse polarity key for voltage readings, except when positive or negative values are displayed directly.

(B) An acceptable arrangement for making the tests shown in paragraph (o)(2)(iii)(A) of this section is to have them under software control with results displayed at one of the system's I/O ports.

(C) A howler circuit for maintenance purposes, if ordered by the owner, shall have output tones which do not interfere with the pushbutton or multifrequency signaling tones. The harmonics of the output tones shall be attenuated at least 26 dB below the fundamental frequency for all load conditions. The frequency stability shall be 2 percent or less for all output tones when the unit is operated in the specified load and environmental range. It shall be possible to vary the output voltage (power) of the howler circuit. It shall remove tone and restore the line to service when the telephone instrument receiver is placed on-hook. The frequency of the output shall be chosen to be distinctive and urgent in order to attract the subscriber's attention to an off-hook situation.

(D) When a dial speed test facility is specified by the owner, it shall be accessed by dialing a special code and shall return to the calling station readily identifiable signals to indicate that the dial speed is slow, normal, or fast.

(E) When the office is arranged for pushbutton dialing, optional facilities shall be provided for testing the pushbutton dialing equipment at the subscriber station.

(F) When a system for testing subscriber lines in remote offices from a test position in a centrally located office is specified by the owner, it shall be capable of working with all the central offices and RST's in the remote areas. This testing equipment shall preferably be solid-state with a minimum of electromechanical devices and shall operate from central office battery. It shall be capable of working over any voice grade telephone circuit and shall not require a dedicated trunk. There shall be no interference to or from “in-band” voice channel tones. When used over a network, the verification or access shall be guarded to prevent unauthorized access by subscribers. Access to this system shall only be available to the test operator in all cases.

(3) Transmission testing. (i) When transmission test circuits are specified in Item 11.3 of appendix A of this section, they shall permit testing of trunks by a distant office without any assistance in the local dial office. Analog test ports shall meet appropriate trunk requirements. If Centralized Automatic Reporting on Trunks (CAROT), or equivalent, is to be used, the equipment at the end office shall comply with Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks—1990, section 8, Item 2.

(ii) Transmission test circuits are available with a variety of options. These include single frequency and multifrequency tone generators with one or more generator output terminals, quiet terminations, and loop around test arrangements for both one-way and two-way trunks.

(iii) Where multifrequency generators are used, they are usually arranged to provide a minimum of three frequencies. With some equipment, up to seven additional frequencies may be provided if needed. No industry standardization of test frequencies is as yet provided. Therefore, it is important that the selection of frequencies, the order in which they are applied and the time interval for application of each frequency be agreed upon by the connecting company and the RUS borrower and listed in appendix A of this section in those situations where connecting companies request the installation of multifrequency generators in borrowers' central offices.

(iv) The milliwatt generator shall be solid-state and generate the analog or digital equivalent of 1004 Hz. The milliwatt generator shall be assigned to a 4-wire analog test port or be digitally generated. All 2-wire and 4-wire voice frequency ports are at a nominal 0 dBm0 level. The level of the 1004 Hz tone generator shall appear at outgoing 2-wire and 4-wire ports at 0 dBm ±0.5 dB. For direct digital connections, the encoded output shall be the digital equivalent of a 0 dBm0 ±0.5 dB signal.

(v) Reference tone generators can be used individually or they can be part of a loop around test arrangement. If both single frequency and multifrequency reference tone generators are to be provided, only one can be arranged as part of a loop around test. Where a loop around arrangement is provided, the generator output can be obtained by dialing singly one of the two line terminals. By dialing the other line terminal singly, usually a 900 ohm resistor in series with a 2.16 microfarad capacitor is connected to the circuit under test to act as a “quiet termination” for noise measurements and other tests. Whenever both line terminals are held simultaneously, both the milliwatt supply and the quiet termination shall be lifted off and a “loop around” condition established. This permits the overall loss to be determined from the distant office by going out over one trunk, looping around in the end office and returning over the other trunk. The insertion loss of this test arrangement when used in a loop around configuration should not exceed 0.1 dB at the frequencies specified for the milliwatt supply. Unless otherwise specified, continuous off-hook supervision is to be provided on both line terminals to prevent collusive calling without charge. It will be permissible to accomplish the quiet termination by opening the 4-wire path internally and to accomplish the loop around by digital switching.

(vi) Provision shall be made so that the milliwatt supply can be manually patched to circuits.

(vii) Test jack access shall be provided for all interoffice trunks of the voice frequency type. The jack access shall be properly designated for line, drop, monitor, and signaling leads plus any other jacks as requested by the owner. This may be accomplished by a set of jacks located at the maintenance center which have access to each trunk on a switching basis.

(p) Traffic—(1) General engineering guidelines. (i) The Traffic Table, based on the Erlang Lost-Calls-Cleared Formula, shall be used for determining the quantity of intraoffice paths, registers, and senders where full availability conditions apply. The following table shows the traffic capacity in CCS for 1 to 200 trunks at nine grades of service.

(ii) The traffic capacity for all interoffice trunks shall be based on full availability, even though the distant office itself is not engineered to provide full availability access.

(iii) The Traffic Table may also be used to determine the approximate traffic capacity of high-usage intertoll trunks. The traffic offered to high-usage groups may be read at B.10, signifying that 10 percent of the traffic overflows to the alternate route. This approximates the HU12 table used by AT&T.

(iv) In reading the trunk quantity from the table, the higher quantity shall be used when the CCS load is three or more CCS over the lower quantity. For example, the number of trunks justified for 294 CCS at B.005 is 16, but for 295 CCS 17 trunks are justified.

(v) Limited availability is not permitted.

(vi) The traffic capacity in the following table should be used for small trunk groups such as pay station, special service trunks, intercept, and PBX trunks, unless otherwise specified in appendix A of this section:

(vii) The percentage of lines equipped for pushbutton dialing is to be used to determine the number of tone receivers. Local registers, if required, shall be supplied on the basis of all dial pulse.

(2) Grade of service. (i) Grade of service specifies the expected performance when there are adequate service facilities for an assumed volume of traffic. It is expressed as a portion of the total traffic during a busy hour that cannot be terminated immediately or within a predetermined time period due to congestion. This places responsibility on the traffic engineers to specify facilities which will be entirely satisfactory to the users and which can be equipped at a price which will be accepted as reasonable.

(ii) The number of calls encountering dial tone delay in excess of 3 seconds, measured over the busy hour of the four high-consecutive week (4HW) period, shall not be more than 1.5 percent.

(iii) The average post dialing delay objective for an intraoffice call shall not exceed 1 second. This includes all connect, operate, and translation time.

(iv) The line to line (intraoffice) network matching loss objective shall be 0.02 or less.

(v) The blocking probabilities related to trunks include both “mismatch” probability and probability of “all trunks busy.” It is likely that the “mismatch” will be negligible in that many digital central offices have essentially nonblocking switching characteristics. The objectives for trunk connections are as follows:

(A) Subscriber to outgoing trunk objective 0.01 or less;

(B) Incoming trunk to subscriber objective 0.02 or less; and

(C) Local trunk tandem objective 0.01 or less.

(vi) Groups of common service circuits are to be engineered utilizing the full availability traffic tables that appear in paragraph (p)(1)(i) of this section at the following stipulated probabilities:

(A) Outgoing trunks to 2/6 MF or dial pulse senders at B.001;

(B) Incoming trunks to 2/6 MF receivers at B.001;

(C) Incoming nondelay dial trunks to receivers at B.001; and

(D) Incoming trunks with start dial at B.01.

(vii) Remote Switching Terminals (RST's) shall meet the same grade of service objectives as the host.

(3) Holding times. For the purpose of estimating the quantity of common control circuits, the following average holding times may be used. These holding times are conservative and represent the average effective and ineffective call. If these holding times are to be used, it must be so stated in appendix A of this section.

(i) The following average call holding times (HT) may be used.

(ii) The following average subscriber dialing holding times may be used (times used to dial digits do not include machine time).

(iii) The following average incoming register holding times may be used (times for digit registrations do not include machine time).

(iv) The following average sender holding times may be used (does not include machine setup and release time).

(4) Traffic data requirements. (i) Traffic measurements are composed of primarily two types—counts and usage. The following types of traffic data recording are required:

(A) Peg count registers shall be incremented when a successful network connection is established to a particular circuit group such as trunks, senders, digital receivers, etc.

(B) Overflow count registers shall be incremented when access to a particular circuit group is denied due to all resource busy condition.

(C) Network blockage count registers shall be incremented due to an unavailability of a path in an access or switching matrix network.

(D) Usage measurements of the length of time associated with a particular setup event or network connection shall be made. Usage data measurements are normally collected by scanning circuit groups resources every 10 or 100 seconds to determine busy/idle states. Measurements are accumulated and read directly in CCS (hundred call seconds).

(E) Service delay measurements shall provide percentage counts of the calls for a particular service that are delayed beyond a specified interval of time, e.g., calls not receiving dial tone within 3 seconds after call origination.

(ii) Traffic data shall be stored in electronic storage registers or block of memory consisting of one or more traffic counters for each item to be measured. The registers listed in paragraph (p)(4)(i) of this section shall be associated with the interoffice trunks, switching network and central control equipment in such a manner that the register readings can be used to determine the traffic load and flow to, from and within the system. Two-way trunks shall be metered to indicate inward and outward seizures. The bidder shall indicate what registers are to be supplied and their purpose.

(iii) The measured data shall be shown on a printout. It should be possible to have local or remote printout, or both. Arrangement shall be made for automatic data printout on command for 15-, 30-, or 60-minute intervals as required, and be arranged for automatic start-stop and in accordance with revenue separation procedures current at the time of contract.

(iv) All traffic records shall have dates and times and office identification.

(q) Transmission—(1) General. The transmission characteristics will be governed by the fact that the switching matrix will be based on digital operation. Unless otherwise stated, the requirements are in terms of analog measurements made from Main Distributing Frame (MDF) to MDF terminals, excluding cabling loss.

(2) Impedance. For the purpose of this section, the nominal input impedance of analog ports in an end office shall be 900 ohms for 2-wire ports and 600 ohms for 4-wire ports. Where the connecting facility or equipment is other than this impedance, suitable impedance matching shall be provided by the bidder when specified by the owner.

(3) Insertion loss. The insertion loss in both directions of transmission at 1004 Hz shall meet the following requirements when measured with a 0 dBm input signal at 900 ohms (or 600 ohms, when required) at a temperature of 77 °F ±9 °F (25 °C ±5 °C).

(i) Trunk-to-trunk or trunk-to-line. The loss shall be set between 0 and 0.5 dB for 2-wire to 2-wire, 2-wire to 4-wire, or 4-wire to 4-wire voice frequency connections.

(ii) Line-to-line. The loss shall be set between 0 and 2 dB.

(iii) Direct digital interface. On a direct digital interface, the loss through the office shall be adjusted to the proper level in the receive side.

(iv) Stability. The long-term allowable variation in loss through the office shall be ±0.5 dB from the loss specified by the bidder.

(4) Frequency response (loss relative to 1004 hz) shall meet the following requirements.

(i) Trunk-to-trunk.

(ii) Line-to-line.

(iii) Trunk-to-line. The trunk-to-line frequency response requirements shall be a compromise between those values specified in paragraphs (q)(4)(i) and (q)(4)(ii) of this section.

(5) Overload level. The overload level at 900 ohm impedance shall be + 3 dBm0.

(6) Gain tracking (linearity) shall meet the following requirements.

(7) Return loss. (i) The specified return loss values are determined by the service and type of port at the measuring (near) end. Two-wire ports are measured (near end) at 900 ohms in series with 2.16 microfarads and 4-wire ports are measured at 600 ohms resistive.

(ii) Far end test terminations shall be as follows:

(A) Loaded line circuit—1650 ohms in parallel with the series combination of .005 microfarads and 100 ohms;

(B) Nonloaded line circuit—800 ohms in parallel with the series combination of .05 microfarads and 100 ohms;

(C) Special service line circuit including electronic lines and carrier lines—900 ohms in series with 2.16 microfarads;

(D) Two-wire trunk—900 ohms in series with 2.16 microfarads; and

(E) Four-wire trunk—600 ohms.

(iii) For trunk-to-trunk (2-wire or 4-wire) connections the echo return loss (ERL) shall be 27 dB, minimum and the singing return loss (SRL) shall be 20 dB, minimum low and 23 dB, minimum high.

(iv) For trunk-to-line (2-wire or 4-wire) connections the ERL shall be 24 dB, minimum and the SRL shall be 17 dB, minimum low and 20 dB, minimum high.

(v) For line-to-line or line-to-trunk (2-wire or 4-wire) connections the ERL shall be 18 dB, minimum and the SRL shall be 12 dB, minimum low and 15 dB, minimum high.

(8) Longitudinal balance. The minimum longitudinal balance, with dc loop currents of 20 to 70 mA, shall be 60 dB at all frequencies between 60 and 2000 Hz, 55 dB at 2700 Hz and 50 dB at 3400 Hz. The method of measurement shall be as specified in the IEEE Std 455-1985, IEEE Standard Test Procedure for Measuring Longitudinal Balance of Telephone Equipment Operating in the Voice Band. Source voltage level shall be 10 volts root-mean-square (rms).

(9) 60 hz longitudinal current immunity. Under test conditions with 60 Hz, the system noise shall be no greater than 23 dBrnC0 as measured using the configuration in Figure 1.

Figure 1—Measuring the Effects of Low Frequency Induction Notes: 1. 900 ohm termination, C-message weighting, hold coil off 2. SNC Noise Choke 35 W, or equivalent 3. Test at 0.020 Adc and 0.070 Adc 4. 2 ±0.001 microfarad, 150 Vdc

(10) Steady noise (idle channel at 900 ohms impedance) measured on a terminated call shall be 23 dBrnC0 maximum and average 18 dBrnC0 or less. The 3K Hz Flat noise should be less than 35 dBrnC0 as an objective.

(11) Impulse noise. The central office switching equipment shall be capable of meeting an impulse noise limit of not more than five counts exceeding 54 dBrnC0 voice band weighted in a 5-minute period on six such measurements made during the busy hour. A Northeast Electronics Company TTS 4002 Impulse Noise Counter, Wilcom T194C, Hewlett Packard 4945, or equivalent, should be used for the measurements. The measurement shall be made by establishing a normal connection from the noise counter through the switching equipment in its off-hook condition to a quiet termination of 900 ohms impedance. Office battery and signaling circuit wiring shall be suitably segregated from voice and carrier circuit wiring, and frame talking battery filters provided, if and as required, in order to meet these impulse noise limits.

(12) Crosstalk coupling. Worst case equal level crosstalk is to be 75 dB minimum in the range 200-3400 Hz. This is to be measured between any two paths through the system connecting a 0 dBm0 level tone to the disturbing pair.

(13) Quantizing distortion. (i) The switching system shall meet the following requirements.

(ii) Due to the possible loss of the least significant bit on direct digital connections, a signal to distortion degradation of up to 2 dB may be allowed where adequately justified by the bidder.

(14) Absolute delay. The absolute one-way delay through the switching system, excluding delays associated with RST switching, shall not exceed 1000 microseconds analog-to-analog measured at 1800 Hz.

(15) Envelope delay distortion. On any properly established connection, the envelope delay distortion shall not exceed the following limits.

(16) Digital error rate. The digital switching system shall not introduce an error into digital connections which is worse than one error in 10 8 bits averaged over a 5-minute period.

(17) Battery noise. Noise across battery at power board distribution bus terminals shall not exceed 35 dBrnC during the busy hour.

(18) Radio and television interference. The central office switching equipment shall be designed and installed so that radiation of high frequency noise will be limited so as not to interfere with radio and television receivers.

(r) Timing intervals—(1) Type of equipment required. The equipment for providing the specified timing intervals shall be solid-state.

(2) Tolerance. Where a range of time is specified as minimum and maximum, the lower limits shall be considered as controlling and the variation between this minimum and the actual maximum shall be kept as small as practicable. In no case shall the quoted upper limit be exceeded.

(3) Permanent signal timing. Lockout shall occur after an interval of 20 to 30 seconds after receipt of dial tone if a “permanent” condition occurs prior to the transmission of dial pulses or pushbutton dialing signals. This interval may be reduced appreciably during periods of heavy traffic.

(4) Partial dial timing. Partial dial timing shall be within 15 to 37 seconds. This timing may be reduced appreciably during periods of heavy traffic.

(5) Charge delay timing. Charge delay timing shall be within 2 seconds.

(6) Called party disconnect timing. Timed disconnect of a terminating path under control of the called party shall be 10 to 32 seconds.

(7) Timing intervals for signals involved in distance dialing. Timing intervals shall be provided to meet the requirements for distance dialing equipment, which have been established in Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks—1990. Some of the more important times which this document specifies are for:

(i) Disconnect signal;

(ii) Wink signal;

(iii) Start dialing signal;

(iv) Pulse delay signal;

(v) Go signal;

(vi) Digit timing; and

(vii) Sender, register, and link attachment timing.

(s) Power requirements and equipment—(1) Operating voltage. The nominal operating voltage of the central office shall be 48 volts dc, provided by a battery with the positive side tied to system ground.

(2) Batteries. (i) When battery cells of the lead antimony type are specified, the pasted plate type shall be considered adequate.

(ii) When lead calcium cells are specified, no cell shall differ from the average voltage of the string of fully charged cells by more than ±0.03 volt when measured at a charging rate in amperes equivalent to 10 percent of the ampere hour capacity of the cells. Similarly, when cells are fully charged and floating between 2.30 and 2.33 volts per cell, the cell voltage of any cell in a given string shall not differ more than ±0.03 volt from the average. These requirements are for test purposes only and do not apply to operating conditions.

(iii) Voltage readings shall be corrected by a temperature coefficient of 0.0033 volt per degree F (0.006 per degree C), whenever temperature variations exist between cells in a given string. This correction factor shall also be applied when comparing cell voltages taken at different times and at different temperatures. The correction factor shall be added to the measured voltage when the temperature is above 77 °F (25 °C) and subtracted when the temperature is below 77 °F (25 °C).

(iv) The specific gravity readings of lead antimony cells at full charge shall be 1.210 ±.010 at 77 °F (25 °C) at maximum electrolyte height.

(v) When counter cells are supplied by the bidder, they shall be the dry counter electromotive force (CEMF) type.

(vi) When lead antimony batteries are specified, they shall be designed to last a minimum of 10 years when maintained on a full float operation between 2.15 and 2.17 volts per cell. When lead calcium batteries are specified, they shall be designed to last a minimum of 20 years when maintained on full float operation between 2.17 and 2.25 volts per cell. The battery shall be clearly designated as “antimony” or “calcium” by means of stencils, decals or other devices.

(vii) Each battery cell shall be equipped with an explosion control device.

(viii) The battery size shall be calculated in accordance with standard procedures. The battery in no case shall have a reserve capacity in ampere hours less than four times the current capacity of the largest charger.

(3) Charging equipment. (i) Charging shall be on a full float basis. The rectifiers shall be of the full wave, self-regulating, constant voltage, solid-state type and shall be capable of being turned on and off manually.

(ii) When charging batteries, the voltage at the battery terminals shall be adjustable and shall be set at the value recommended for the particular battery being charged, providing it is not above the maximum operating voltage of the switching system equipment. The voltage shall not vary more than plus or minus 0.02 volt per cell between 10 percent load and 100 percent load. Between 3 percent and 10 percent load, the output voltage shall not vary more than plus or minus 0.04 volt per cell. Beyond full load current, the output voltage shall drop sharply. The output voltage shall be maintained with the line voltage variations of plus or minus 10 percent. Provision shall be made to change the output voltage of the rectifier manually to 2.25 volts per cell to provide an equalization charge on the battery.

(iii) The charger noise shall not exceed 22 dBrnC when measured with a suitable noise measuring set and under the rated battery capacitance and load conditions as determined in Figure 2.

Figure 2—Charger Noise Test The manufacturer may elect to eliminate the capacitor C from the measurement. A. Capacitance in µF = 30,000 µF per ampere-hour per cell. For example, 25 cells at 100 ampere-hour would be equivalent to a capacitance of:

(30,000 × 100) / 25 = 120,000 µF

B. The value of the resistive load R is determined by the nominal battery voltage in volts divided by the full load rating in amperes. For example, for a 48 volt battery and a full load current of 24 amperes, the load resistance R is 48/24 = 2 ohms of appropriate power handling capacity.

(iv) The charging equipment shall indicate a failure of charging current, whether due to ac power failure, an internal failure in the charger, or to other circumstances which might cause the output voltage of the charger to drop below the battery voltage. Where a supplementary constant current charger is used, an alarm shall be provided to indicate a failure of the charger.

(v) Audible noise developed by the charging equipment shall be kept to a minimum. Acoustic noise resulting from operation of the rectifier shall be expressed in terms of dB indicated on a sound level meter conforming to ANSI S1.4-1983, Specification for Sound Level Meters, and shall not exceed 65 dB (A-weighting) measured at any point 5 feet (152.4 cm) from any vertical surface of the rectifier.

(vi) The charging equipment shall be designed so that neither the charger nor the central office switching equipment is subject to damage in case the battery circuit is opened for any value of load within the normal limits.

(vii) The charging equipment shall have a capacity to meet the requirements of central office size and special requirements of the owner in appendix A of this section.

(viii) Minimum equipment requirement for chargers is one of the following:

(A) Two chargers either capable of carrying the full office load as specified in Item 12 of appendix A of this section; or

(B) Three chargers each capable of carrying half the office load as specified in Item 12 of appendix A of this section.

(4) Miscellaneous voltage supplies. (i) Any power supply required for voltages other than the primary battery voltage shall be provided by either a solid-state dc-to-dc converter or dc-to-ac inverter, operating from the central office battery or from a separate battery and charger. These power supplies shall meet the noise limit specified for chargers in paragraph (s)(3)(iii) of this section, except the capacitor “C” shall be eliminated and the resistive load “R” shall be determined by the nominal output voltage in volts divided by the full load current rating in amperes. This requirement does not preclude the use of commercial ac power to operate input/output devices.

(ii) Power converters required for the purpose of providing various operating voltages to printed circuit boards or similar equipment employing electronic components shall be provided in duplicate with each unit capable of immediately assuming the full operating load upon failure of a unit. An exception to the duplicate power converter requirement permits nonduplicated power converter(s) to be utilized where there is full compliance with the following criteria.

(A) The failure of any single nonduplicated power converter shall not reduce the grade of service of common control and service circuits to any individual line or trunk by more than 50 percent.

(B) The failure of any single nonduplicated power converter shall not reduce the traffic carrying capacity of any interoffice trunk group by more than 50 percent.

(C) In central office switching systems of 400 or more equipped lines, any single nonduplicated power converter failure shall not cause a complete loss of service to more than 100 equipped lines.

(D) In central office switching systems of less than 400 equipped lines, any single nonduplicated power converter failure shall not cause a complete loss of service to more than 25 percent of the total equipped lines.

(5) Ringing generators. Ringing generators supplied on an ancillary basis shall be selected from RUS Bulletin 1755I-100, List of Materials Acceptable for Use on Telephone Systems of RUS Borrowers. Regardless of whether the ringing is generated on an ancillary basis or is generated integrally to the switching system, the ringing equipment shall meet the requirements of this section.

(i) Ringing equipment provisioning. (A) Redundant ringing equipment shall be provided. There shall be automatic transfer to the redundant equipment within the period of one ringing cycle, in case of failure of the equipment in use (either regular or standby). Automatic transfer shall not take place under any other conditions. Manual transfer in each direction shall be provided.

(B) An exception to the redundant ringing equipment requirement permits nonredundant ringing equipment to be utilized where there is full compliance with the following service criteria.

(1) In a central office switching system of 400 or more equipped lines, a single nonduplicated ringing source failure shall not cause the complete loss of ringing capability to more than 100 lines.

(2) In a central office switching system of less than 400 equipped lines, a single nonredundant ringing source failure shall not cause the complete loss of ringing capability to more than 25 percent of the total equipped lines.

(ii) Output voltage. (A) The ringing generators shall have an output voltage which approximates a sine wave and, as a minimum, shall be suitable for ringing straight-line ringers. Although not a requirement for RUS listing, decimonic, synchromonic, or harmonic ringing may also be specified in appendix A of this section.

(B) The ringing generator shall obtain its energy from the nominal 48-volt office battery.

(C) The output of each generator shall have three or more voltage taps or a single tap with associated variable control. Taps or control shall be easily accessible as installed in the field. Software control of ringing generator outputs via I/O devices may be provided in lieu of taps. The taps, or equivalent, shall be designated L, M, and H. The variable control shall have a locking device to prevent accidental readjustment. The outputs at the terminals of the generators with a voltage input of 52.1 volts and rated full resistive load shall be as follows for the ringing frequencies provided:

(D) No voltages in excess of the values in column H of the table in paragraph (s)(5)(ii)(C) of this section shall be provided at the output taps. Additional intermediate and/or lower taps may be provided without restriction.

(iii) Voltage regulation. (A) The output voltage for resistive, capacitive power factor of 0.8, and inductive power factor of 0.5 loads from no load to full rated output with 52.1 volts input battery shall not vary more than ±3 percent from the output voltage measured at 1/2 rated output, 1.0 power factor with 52.1 volts dc input applied.

(B) The output voltage for resistive, capacitive power factor of 0.8, and inductive power factor of 0.5 from no load to full rated output with input battery variations between 48-56 volts dc shall not vary more than ±10 percent from the output voltage measured at 1/2 rated output and 1.0 power factor with 52.1 volts dc input applied.

(C) The output voltage for resistive, capacitive power factor of 0.8, and inductive power factor of 0.5 loads from no load to full rated output and with input battery variations between 44-56 volts dc shall not vary more than + 10/−15 percent from the output voltage measured at 1/2 rated output and 1.0 power factor with 52.1 volts dc input applied.

(iv) Cross ringing. Unwanted voltage caused by harmonic distortion or intermodulation distortion shall not exceed 15 volts rms when measured within ±5 Hz of any other assigned ringing frequency under any condition of load or input battery specified by paragraph (s)(5)(iii) of this section.

(v) Frequency stability. At ambient temperature of 70 ° ±5 °F (21 ° ±0.3 °C), for any combination of capacitive power factor of 0.8, inductive power factor of 0.5, and resistive loads with variations in input battery ranging from 44 to 56 volts, the output frequency shall not vary more than ±1/3 Hz or ±1 percent, whichever is less stringent. At temperatures between 15 °F (4 °C) to 130 °F (54 °C), and for any combination of resistive load and variations in input battery ranging from 44-56 volts, the output frequency shall not vary more than ±1/3 Hz or ±1 percent, whichever is less stringent.

(vi) Self-protection on overloads. The ringing generator equipment shall be capable of withstanding a short circuit across any pair of output terminals for a period of 5 minutes without fuse operation or damage.

(6) Interrupter equipment. (i) The interrupter shall be an integral part of the switching system and shall be controlled by any call processor or equivalent.

(ii) The ringing cycle provided by the interrupter equipment shall not exceed 6 seconds in length. The ringing period shall be 2 seconds.

(7) Power panels. (i) Battery and charger control switches, dc voltmeters, dc ammeters, fuses and circuit breakers, supervisory and timer circuits shall be provided as required. Voltmeters shall be provided as specified by the owner.

(ii) Portable or panel mounted frequency meters shall be provided as specified by the owner unless the system is equipped to measure actual ringing generator voltage and frequency outputs internally. If the system is equipped to make such measurements and print the results, the bidder is not required to provide a frequency meter.

(iii) Power panels, cabinets and shelves, and associated wiring shall be designed initially to handle the exchange when it reaches its ultimate capacity as specified by the owner.

(iv) The power panel shall be of the “dead front” type.

(t) Main distributing frames. (1) The main distributing frame shall provide terminals for terminating all incoming cable pairs. Arresters shall be provided for all incoming cable pairs, or for a smaller number of pairs if specified, provided an acceptable means of temporarily grounding all terminated pairs which are not equipped with arresters is furnished.

(2) The current carrying capacity of each arrester and its associated mounting shall coordinate with a #22 gauge copper conductor without causing a self-sustaining fire or permanently damaging other arrester positions. Where all cable pairs entering the central office are #24 gauge or finer, the arresters and mountings need only coordinate with #24 gauge cable conductors. Item 13 of appendix A of this section designates the gauge of the cable conductors serving the host office. Item 7 of appendix B of this section designates the gauge of the cable conductors serving the RST(s).

(3) Central office protectors shall be mounted and arranged so that outside cable pairs may be terminated on the left side of protectors (when facing the vertical side of the MDF) or on the back surface of the protectors. Means for easy identification of pairs shall be provided.

(4) Protectors shall have a “dead front” (either insulated or grounded) whereby live metal parts are not readily accessible.

(5) Protectors shall be provided with an accessible terminal of each incoming conductor which is suitable for the attachment of a temporary test lead. They shall also be constructed so that auxiliary test fixtures may be applied to open and test the subscriber's circuit in either direction. Terminals shall be tinned or plated and shall be suitable for wire wrapped, insulation displacement or connectorized connections.

(6) If specified in appendix A of this section, each protector group shall be furnished with a factory assembled tip cable for splicing to the entrance cable; the tip cable to be 20 feet (610 cm) in length unless otherwise specified. Factory assembled tip cable shall be #22 gauge and selected from RUS Bulletin 1755I-100, List of Materials Acceptable for Use on Telephone Systems of RUS Borrowers. Tip cable requirements are provided in RUS Bulletin 345-87, PE-87, RUS Specification for Terminating (TIP) Cable. Cables having other kinds of insulation and jackets which have equivalent resistance to fire and which produce less smoke and toxic fumes may be used if specifically approved by RUS.

(7) Protectors shall be mounted on vertical supports, with centers not exceeding 9 inches (22.9 cm). The space between protector units shall be adequate for terminating conductors.

(8) Cable supporting framework shall be provided between the cable entrance and the MDF when overhead cable entrance is specified in Item 14.3.3 of appendix A of this section.

(9) The main distributing frame shall be equipped with a copper ground bus bar having the conductivity of a #6 American Wire Gauge (AWG) copper conductor or a greater conductivity, or may consist of another metal if specifically approved, provided it has adequate cross-sectional area to provide conductivity equivalent to, or better than, bare copper. A guardrail or equivalent shall also be furnished.

(10) Other features not specified in paragraph (t) of this section may be required at the option of the owner, if checked in Item 13.4 of appendix A of this section.

(11) Main frame protector makes and types shall be selected only from RUS Bulletin 1755I-100, List of Materials Acceptable for Use on Telephone Systems of RUS Borrowers. Protectors shall be capable of easy removal.

(u) Electrical protection—(1) Surge protection. (i) Adequate electrical protection of central office switching equipment shall be included in the design of the system. The characteristics and application of protection devices shall be such that they enable the central office switching equipment to withstand, without damage or excessive protector maintenance, the dielectric stresses and currents that are produced in line-to-ground and tip-to-ring circuits through the equipment as a result of induced or conducted lightning or power system fault-related surges. All wire terminals connected to outside plant wire or cable pairs shall be protected from voltage and current surges.

(ii) Central office switching equipment shall pass laboratory tests, simulating the hostile electrical environment, before being placed in the field for the purpose of obtaining field experience. There are five basic types of laboratory tests which shall be applied to exposed terminals in an effort to determine if the equipment will survive. Figure 3 summarizes these tests and the minimum acceptable levels of protection for equipment to pass them.

(iii) Two categories of surge tests. (A) Current surge tests simulate the stress to which a relatively low impedance path may be subjected before main frame protectors break down. Paths with a 100 Hz impedance of 50 ohms or less shall be subjected to current surges, employing a 10 × 1000 microseconds waveshape as defined in Figure 4. For the purpose of determining this impedance, arresters which are mounted within the equipment are to be considered zero impedance. The crest current shall not exceed 500A; however, depending on the impedance of the test specimen this value of current may be lower. The crest current through the sample, multiplied by the sample's 100 Hz impedance, shall not exceed 1000 volts (V). Where sample impedance is less than two ohms, crest current shall be limited to 500A as shown in Figure 5.

Figure 4—Explanation of Surge Waveshape

Surge Waveshape is defined as follows:

Rise Time × Time to Decay to Half Crest Value

(For example, 10 × 1000 µs)

Notes: T1 = Time to determine the rate of rise. The rate of rise is determined as the slope between 10% and 90% of peak voltage or current. T2 = Time to 50% of peak voltage (decay to half value). Figure 5—Explanation of Surge Waveshape VL = Not to exceed 1000V VB = Charging Voltage Z100 = Test Specimen Impedance to be measured at 100 Hz. RP = Parallel Resistance (Waveshape) RS = Series Resistance (Current Limiting)

(B) Sixty Hertz (60 Hz) current-carrying tests should be applied to simulate an ac power fault which is conducted to the unit over the cable pairs. The test should be limited to 10 amperes rms at 60 Hz for a period of 11 cycles (0.1835 seconds) and should be applied longitudinally from line to ground (see Figures 3 and 6 of this section).

Figure 6—60 Hz Current Surge Test V—700 Volts RMS (Approximately 1000V Peak). Z60—Test specimen impedance to be measured at 60 Hz. RS—Series Resistance (current limiting) in each side of line. (Source impedance never less than 50 Ω longitudinal.)

(C) AC power service surge voltage tests should be applied to the power input terminals of ac powered devices to simulate switching surges or lightning-induced transients on the ac power system. The test shall employ a 1.2 × 50 microseconds waveshape with a crest voltage of 2500V. Communications line protectors may be left in place for this test. Borrowers are urged to install commercially available surge protectors at the ac service entrance as part of their COE building program.

(D) Voltage surge tests simulate the voltage stress to which a relatively high impedance path may be subjected before primary protectors break down and protect the circuit. To assure coordination with the primary protection while reducing testing to the minimum, voltage surge tests should be conducted at a 1000 volts with primary arresters removed for devices protected by carbon blocks, or the + 3 sigma dc breakdown of other primary arresters. Surge waveshape should be 10 × 1000 microseconds.

(E) Arrester response delay tests are designed to stress the equipment in a manner similar to that caused by the delayed breakdown of gap type arresters when subjected to rapidly rising voltages. Arresters shall be removed for these tests, the peak surge voltage should be the + 3 sigma breakdown of the arrester in question on a voltage rising at 100V per microsecond and the time for the surge to decay to half voltage shall equal at least the delay time of the tube, as explained in Figure 7.

Figure 7—Explanation of Arrester Response Delay Time The delay time is that period of time when the potential across an arrester exceeds its dc firing level.

(iv) Five applications of each polarity for the surge tests and three for the 60 Hz Current Carrying Test are the minimum required. All tests should be conducted with not more than 1 minute between consecutive applications in each series of three or five to a specific configuration so that heating effects will be cumulative. As not all tests are required in every application, nonapplicable tests should be omitted. Tests should be conducted in the following sequence.

(A) Current Impulse Test.

(B) Sixty Hertz (60 Hz) Current Carrying Test.

(C) AC Power Service Impulse Voltage Test.

(D) Voltage Impulse Test.

(E) Arrester Response Delay Test.

(v) Tests should be applied between each of the following terminal combinations for all line operating conditions.

(A) Line tip to ring.

(B) Line ring to ground.

(C) Line tip to ground.

(D) Line tip to ring tied together to ground.

(2) Extraordinary surge protection. A central office or RST may be located in an area where ground conditions prevent the reasonable economic achievement of a low resistance to ground and/or there exists a greater than average probability of surge damage. Such an unusually hostile operating environment shall be recognized and taken into consideration by the bidder in the engineering and specification of the central office switching system and line protection. This subject of operating environment, ground conditions, etc., should be discussed at the time of technical presentation to assure the owner that adequate system protection will be provided by the bidder.

(3) Dielectric strength. Arresters shall be removed for all dielectric strength tests. The duration of all dielectric strength tests shall be at least 1 second. The applied potential shall equal or exceed the + 3 sigma dc breakdown voltage of the arrester, provided by the COE manufacturer. Direct current potentials shall be applied between all line terminals and equipment chassis and between these terminals and grounded equipment housings in all instances where the circuitry is dc open circuit from the chassis, or connected to the chassis through a capacitor.

(4) Insulation resistance. Following the dielectric tests, the insulation resistance of the installed electrical circuits between wires and ground, with the normal equipment grounds removed, shall not be less than 10 megohms at 500 volts dc at approximately room temperature (68 °F (20 °C)) and at a relative humidity of approximately 50 percent. The measurement shall be made after the meter stabilizes, unless the requirement is met sooner. Arresters shall be removed for these tests.

(5) Self-protection. (i) All components shall be of the self-protecting type, capable of being continuously energized at rated voltage without injurious results.

(ii) The unit equipment shall not be permanently damaged by accidental short circuits of any duration across either the central office side tip and ring or the line side tip and ring. A test is to be made with the unit energized at the highest recommended voltages.

(6) Static discharge. Assemblies subject to damage by static discharge shall be identified and special handling instructions shall be supplied.

(v) Miscellaneous—(1) Office wire. All office wire shall be of soft annealed tinned copper wire meeting the requirements of ASTM Specification B 33-91, Standard Specification for Tinned Soft or Annealed Copper Wire for Electrical Purposes, and of suitable cross-section to provide safe current carrying capacity and mechanical strength. The insulation of installed wire, connected to its equipment and frames, shall be capable of withstanding the same insulation resistance and dielectric strength requirements as given in paragraphs (u)(3) and (u)(4) of this section at a temperature of 120 °F (49 °C) and a relative humidity of 90 percent.

(2) Wire wrapped terminals. These terminals are preferred and where used shall be of a material suitable for wire wrapping. The connections to them shall be made with a wire wrapping tool with the following minimum number of successive nonoverlapping turns of bare tinned copper wire in contact with each terminal.

(i) 6 Turns of 30 Gauge.

(ii) 6 Turns of 26 Gauge.

(iii) 6 Turns of 24 Gauge.

(iv) 5 Turns of 22 Gauge.

(3) Protection against corrosion. All metal parts of equipment frames, distributing frames, cable supporting framework, and other exposed metal parts shall be constructed of corrosion resistant materials or materials plated or painted to render them adequately corrosion resistant.

(4) Screws and bolts. Screw threads for all threaded securing devices shall be of American National Standard form in accordance with Federal Standard H28, Screw-Thread Standards for Federal Services, unless exceptions are granted to the manufacturer of the switching equipment. All bolts, nuts, screws, and washers shall be of nickel-copper alloy, steel, brass or bronze.

(5) Temperature and humidity range. The supplier shall furnish the operating temperature and humidity ranges of the equipment being provided in order that adequate heating and cooling may be supplied (see Items 5.2.1 and 5.2.2 of appendix C of this section).

(6) Stenciling. Equipment units and terminal jacks shall be adequately designated and numbered. They shall be stenciled so that identification of equipment units and leads for testing or traffic analysis can be made without unnecessary reference to prints or descriptive literature.

(7) Equipment frame design. For newly designed systems, consideration should be given to the desirability of providing frames which can be installed in rooms of normal ceiling height [up to 10 feet (305 cm)]. Where feasible, frames and equipment units shall be designed for ready portability and high salvage value.

(8) Quantity of equipment bays. Consistent with system arrangements and ease of maintenance, space shall be provided on the floor plan for an orderly layout of future equipment bays that will be required for anticipated traffic when the office reaches its ultimate size. Readily accessible terminals shall be provided for connection to interbay and frame cables to future bays. All cables, interbay and intrabay (excluding power), if technically feasible, shall be terminated at both ends by use of connectors.

(w) Remote switching terminal (RST)—(1) General. The RST is a remotely located digital switching terminal which is placed at a subordinate wire center for subscriber lines and is a part of the host central office from a switching standpoint, and has hardware interchangeable with the host office, except for items that are applicable only to RST control and associated peripheral equipment. This does not preclude the use of existing in-service remote units on a new or upgraded host central office of the latest series generic or release.

(2) Span line. The RST is to be connected to the host central office via a means compatible with T1 type span lines using a DS-1 interface. This connection will be for control supervision and subscriber communication. The RUS equipment specification for a span line is PE-60.

(3) Switching. (i) The RST may have its switching functions controlled either by the host central office stored program control processors or by local subordinate processors which communicate with the host office processors.

(ii) As long as the connecting span line is intact, the subscribers served by the RST shall have all features, traffic capacity, and services including busy verification, available to all other subscribers in the system.

(iii) The RST shall have available an emergency call processing option which permits calling among all subscribers and from subscribers to emergency numbers within the RST if control link connections to the host central office are severed or otherwise disabled. The RST shall be capable of rerouting normally used emergency numbers, such as 911, to predetermined line terminations in this emergency stand-alone operating condition. This RST emergency call processing option shall be provided only when specified by the owner in Item 6.1 of appendix B of this section.

(4) Subscriber line test. (i) Means shall be available on an optional basis to the maintenance personnel to make subscriber line tests from a common location for all subscriber lines including the RST.

(ii) If tests in paragraph (w)(4)(i) of this section are not requested by the owner for a particular installation, a subscriber loop test set (see paragraph (o)(2)(iii)(A) of this section) shall be supplied at the RST with a means to access all lines.

(5) Housing. When housed in a building supplied by the owner, a complete floor plan including ceiling height, power outlets, cable entrances, equipment entry and travel, type of construction, and other pertinent dimensions shall be supplied with this section.

(6) Power—(i) Chargers. A single charger meeting the requirements of paragraph (s)(3) of this section (with the exception of paragraph (s)(3)(viii) of this section) is required. An additional charger capable of carrying the full load or a combination of three chargers each capable of carrying half the load shall be supplied if redundant chargers are specified in appendix B of this section.

(ii) Ringing equipment provisioning. (A) Ringing sources shall be supplied in duplicate.

(B) An exception to the duplicated ringing source requirement permits nonduplicated ringing source(s) to be utilized where there is full compliance with the following service criteria.

(1) In a remote switching terminal (RST) of 400 or more equipped lines, a single nonduplicated ringing source failure shall not cause the complete loss of ringing capability to more than 100 lines.

(2) In a remote switching terminal (RST) of less than 400 equipped lines, a single nonredundant ringing source failure shall not cause the complete loss of ringing capability to more than 25 percent of the total equipped lines.

(iii) Power converter. (A) Power converters required for the purpose of providing various operating voltages to printed circuit boards or similar equipment employing electronic components shall be provided in duplicate with each unit capable of immediately assuming the full operating load upon failure of a unit.

(B) An exception to the duplicate power converter requirement permits nonduplicated power converter(s) to be utilized where there is full compliance with the following criteria.

(1) The failure of any single nonduplicated power converter shall not reduce the grade of service of common control and service circuits to any individual line or trunk by more than 50 percent.

(2) The failure of any single nonduplicated power converter shall not reduce the traffic carrying capacity of any trunk group or service links to a host office by more than 50 percent.

(3) In a remote switching terminal (RST) of 400 or more equipped lines, any single nonduplicated power converter failure shall not cause a complete loss of service to more than 100 equipped lines.

(4) In a remote switching terminal (RST) of less than 400 equipped lines, any single nonduplicated power converter failure shall not cause a complete loss of service to more than 25 percent of the total equipped lines.

(7) Alarm. Sufficient system alarm points shall be provided from the RST to report conditions to the host alarm system.

(x) Responsibilities of the bidder—(1) Central office layout. (i) The successful bidder shall furnish tentative floor plan layout drawings showing the arrangement of the equipment and the dimensions of major equipment units. These drawings shall include minimum door dimensions and ceiling heights required for installation, maintenance and ventilation. If requested by the owner, the floor plan shall be such that the battery, charger, power board, main distributing frame and wire chief's test equipment are isolated from the other equipment by a partition.

(ii) The layout drawings shall also show provision for the ultimate capacity of the central office as specified by the owner.

(iii) After approval by the owner of the tentative floor plan, and within 10 calendar days after approval of the contract by the Administrator, the owner shall furnish the bidder the necessary data on the actual floor plan. Within 20 calendar days after receiving the necessary building data, the bidder shall then supply floor plan drawings showing exact locations of all equipment, both initial and ultimate, including points where connection to commercial power are required, with voltage and wattage indicated at each point. Within 20 calendar days after receiving the floor plan drawings from the bidder, the owner shall approve these drawings or take the necessary steps to have the drawings changed to meet his approval. The layout planning must be so coordinated between the owner and the bidder as not to delay the scheduled equipment installation date.

(2) Shipment of main distributing frame (MDF). The bidder shall ship the MDF equipment, with all necessary instructions to permit its installation by the owner, at the time requested by the owner in writing, provided such time is not earlier than 90 days prior to the date specified for the shipment of the rest of the central office equipment. If the owner or the owner's agent installs the main distributing frame, the owner shall assume the responsibility and the expense of proper installation according to information furnished by the bidder.

(3) Drawings and printed material. (i) The bidder shall supply instructional material for each exchange involved at the time of delivery of the equipment. It is not the intent of this section to require system documentation necessary for the repair of individual circuit boards. The bidder shall supply three complete sets of legible drawings, each set to include all of the following drawings and documentation:

(A) A floor plan showing exact dimensions and location of each equipment frame or item to a convenient scale;

(B) A block schematic drawing showing the various equipment components in the system, and their identifying circuit number (e.g., MDF, line circuits, memory, trunks, etc.);

(C) Drawings of major equipment items such as frames, with the location of major component items of equipment shown;

(D) Individual functional drawings for electrical circuits in the system;

(E) A detailed description of the operation of each circuit down to a circuit package level;

(F) Wiring diagrams indicating the specific method of wiring used on each item of equipment and interconnection wiring between items of equipment;

(G) Sufficient software documentation to maintain and service the system, including drawings showing principal aspects of the software architecture;

(H) Individual maintenance drawings covering each equipment item that contains replaceable parts, appropriately identifying each part by name and part number, or, complete ordering instructions for all replaceable parts if individual item drawings are not provided; and

(I) Job drawings including all drawings that are individual to the particular office involved, such as main frame, power panel, test board, etc.

(ii) The following information shall also be furnished:

(A) Complete index of the required drawings;

(B) Explanation of electrical principles of operation of the overall switching system;

(C) List of tests which can be performed with each piece of test equipment furnished, and explanation of the method of performing each test;

(D) Sample of each form recommended for use in keeping records of tests;

(E) Criteria for analyzing results of tests and determining appropriate corrective action;

(F) General notes on the methods of isolating equipment faults to specific printed circuit cards in the equipment;

(G) List of typical troubles which might be encountered, together with general indications as to the probable location of each trouble;

(H) Special office grounding requirements;

(I) A site specific central office ground system acceptance checklist that is consistent with industry practice; and

(J) A site specific layout of the master ground bar (MGB) showing assignment of P, A, N, and I equipment areas.

(4) Distributing frame wire. The bidder shall provide sufficient tinned copper conductor distributing frame wire for the initial installation. The insulation of this wire shall be such that it will not support combustion. The insulation shall have good abrasion resistance and cut-through properties, exhibit good solder heat resistance, and be suitable for wire wrap connections or insulation displacement connections.

(5) Technical assistance service. A technical assistance service shall be made available to assist the owner and its maintenance personnel on a 24-hour, 7 days a week basis. There is to be assistance available for both hardware and software problems. The necessary interface devices shall be supplied by the bidder.

(6) Spare parts. (i) The spare parts bid price shall be based upon the required quantities of spares shown in Item 6.2 of appendix C of this section, and shall be added to the base bid for comparison purposes in awarding the bid. It is the supplier's responsibility to provide all spares required by this section. If the supplier neglects to list certain spare parts in Item 6.2 of appendix C of this section, but they are necessary to comply with this section, they shall be provided by the supplier at no additional cost to the owner.

(A) “Units” are defined as user replaceable components used in the central office equipment. “Spare Parts” are direct replacements for units. Spare parts are necessary for the maintenance and diagnostic operations where the suspected faulty unit may be removed and a spare part substituted in anticipation that the trouble will be cleared.

(B) Examples of units for which spare parts should be furnished are printed circuit cards; circuit pack assemblies; fuses; and power supplies.

(C) Spare parts are not required as part of this addendum for items such as connectorized cables, nuts, bolts, and similar hardware; nor for items which can be obtained from sources other than the bidder such as battery cells, chargers, powerboards, magnetic tape transport assemblies, disk drives, ringing machines, recorded announcement machines, loop extenders and voice frequency repeaters, fire bars, teletypewriters, and video monitors.

(D) When 100 or more like units are used in the hosts and RST's to be bid, the quantity of spares to be furnished is determined by multiplying the total number of like units in the contract by .05 or .03, as applicable, and rounding off to the next lowest integer. For example, 119 Class 1 units require five spares; 120 require six.

(E) When alternates are required, the price of the spare parts for the alternates shall be included with the price of the alternate.

(F) For equipment in which the line cards consist of a number of plug-in “daughter” boards on a “mother” board, the line card is defined as the “daughter” board unit. In a similar manner for those designs which have line cards backed up by a “control card,” the “control card” is not, by definition, a line card.

(G) The quantities of spare parts determined in paragraph (x)(6)(vi) of this section are a minimum quantity. The bidder may add quantities of spare parts to bring the number of spare parts up to the bidder's list of spare parts necessary for proper operation in the field.

(ii) A Class 1 unit does not have automatic transfer to a redundant or standby pool of identical units, and provides any function for 24 or more lines or trunks or for all trunks in a group. Nonredundant digital trunk interfaces are included in this category.

(iii) A Class 2 unit has automatic transfer to a redundant or standby pool of identical units, and provides any function for 24 or more lines or trunks or for all trunks in a group. Redundant digital trunk interfaces and units of a redundant stored program processor are included in this category.

(iv) A Class 3 unit does not have automatic transfer to a redundant or standby pool of identical units and provides any function for no more than 23 lines or trunks or for less than all trunks in a group. Nonredundant analog trunks are included in this category. Excluded from this category are line cards, which are in Class 4.

(v) A Class 4 unit has automatic transfer to a redundant or standby pool of identical units and provides any function for no more than 23 lines or trunks or for less than all trunks in a group. Also, any line cards are in Class 4.

(vi) The spare parts for all of the hosts and the RST's included in this contract shall be provided as follows:

(vii) As a part of the response to the bid, the supplier shall furnish a list of units used by class and a list of spare parts to be furnished with this contract. This list shall be placed in Item 6.2 of appendix C of this section for only one of the host specifications included in the entire contract.

(7) Environmental requirements. The bidder shall specify the environmental conditions necessary for safe storage and satisfactory operation of the equipment being bid. If requested, the bidder shall assist the owner in planning how to provide the necessary environment for the equipment.

(8) Unit costs for cost separation purposes. The successful bidder shall present a cost breakdown of the central office equipment on a discrete element basis 90 days after installation completion. This shall include the various frames, switching and transmission components, and software.

(9) Single-point grounding system acceptance. Qualified representatives of the central office system supplier and the owner are to conduct a thorough joint acceptance audit of the grounding system prior to the central office being placed into service. A grounding system acceptance checklist provided by RUS, which is consistent with standard industry practice, will be used in conducting this audit. All required grounding system corrections are to be made prior to placing the central office system into full service operation. The successful completion of this grounding system audit will constitute an acceptance on the part of both parties, the owner and the central office supplier (refer to paragraph (y)(5) of this section, and appendix D of this section).

(y) Installation. The following responsibilities apply to the central office equipment installation and Remote Switching Terminal (RST) installations, unless otherwise noted.

(1) Responsibilities of owner. The owner shall:

(i) Allow the bidder and its employees free access to the premises and facilities at all hours during the progress of the installation;

(ii) Take such action as necessary to ensure that the premises are dry and free from dust and in such condition as not to be hazardous to the installation personnel or the material to be installed (not required for an RST installed in a self-contained environmentally controlled cabinet);

(iii) Provide heat or air conditioning when required and general illumination in rooms in which work is to be performed or materials stored (not required for an RST installed in a self-contained environmentally controlled cabinet);

(iv) Provide suitable openings in buildings to allow material to be placed in position (not required for an RST installed in a self-contained environmentally controlled cabinet);

(v) Provide the necessary conduit and commercial and dc-ac inverter output power to the locations shown on the approved floor plan drawings; provide 120 volts, 60 Hz commercial power equipped with a secondary arrester and a reasonable number of outlets for test, maintenance and installation equipment; provide suitable openings or channels and ducts for cables and conductors, from floor to floor and from room to room; provide an acceptable central office grounding system and at a ground resistance level that is reasonable for office site conditions (not required for an RST installed in a self-contained environmentally controlled cabinet);

(vi) Provide the necessary wiring, central office grade ground and commercial power service, with a secondary arrester, to the location of an exterior RST installation based on the voltage and load requirements furnished by the bidder;

(vii) Test at the owner's own expense all lines and trunks for continuity, leakage and loop resistance and ensure that all lines and trunks are suitable for operation with the central office equipment specified;

(viii) Make alterations and repairs to buildings necessary for proper installation of material, except to repair damage for which the bidder or its employees are responsible;

(ix) Connect outside cable pairs on the distributing frame and run all line and trunk jumpers (those connected to protectors);

(x) Furnish all trunk, line, and party assignment information to permit the bidder to program the data base memory within a reasonable time prior to final testing;

(xi) Release for the bidder's use such portions of the existing plant as are necessary for the proper completion of such tests as require coordination with existing facilities including facilities for T1 span lines with properly installed repeaters between the central office and the RST installations;

(xii) Make prompt inspections as it deems necessary when notified by the bidder that the equipment, or any part of the equipment, is ready for acceptance;

(xiii) Provide and install adequate fire protection apparatus, including one or more fire extinguishers or fire extinguishing systems of the gaseous type that has low toxicity and effect on equipment; and

(xiv) Provide necessary access ports for cable, if underfloor cable is selected.

(2) Responsibilities of bidder. The bidder shall:

(i) Allow the owner and its representatives access to all parts of the buildings at all times during the installation;

(ii) Obtain the owner's permission before cutting into or through any part of the building structure such as girders, beams, concrete or tile floors, partitions or ceilings (not applicable to the installation of lag screws, expansion bolts, and similar devices used for fastening equipment to floors, columns, walls and ceilings);

(iii) Be responsible for reporting to the owner any damage to the building which may exist or may occur during its occupancy of the building, repairing all damage to the building due to carelessness of the bidder's workforce, and exercising reasonable care to avoid any damage to the owner's property;

(iv) Consult with the owner before cutting into or through any part of the building structure where the fireproofing or moisture proofing may be impaired;

(v) Take necessary steps to ensure that all fire fighting apparatus is accessible at all times and all flammable materials are kept in suitable places outside the building;

(vi) Not use gasoline, benzene, alcohol, naphtha, carbon tetrachloride or turpentine for cleaning any part of the equipment;

(vii) Install the equipment in accordance with the specifications for the office;

(viii) Run all jumpers, except line and trunk jumpers (those connected to protectors);

(ix) Establish and update all data base memories with subscriber and trunk information as supplied by the owner until an agreed turnover time;

(x) Give the owner notice of completion of the installation at least 1 week prior to completion;

(xi) Permit the owner or its representative to conduct tests and inspections after installation has been completed in order that the owner may be assured that the requirements for installation are met;

(xii) Allow access, before turnover, by the owner or its representative, upon request, to the test equipment which is to be turned over as a part of the office equipment, to permit the checking of the circuit features which are being tested and to permit the checking of the amount of connected equipment to which the test circuits have access;

(xiii) Make final charger adjustments using the manufacturer's recommended procedure;

(xiv) Notify the owner promptly of the completion of work of the central office, or such portions as are ready for inspection;

(xv) Correct promptly all defects for which the bidder is responsible;

(xvi) Provide the owner with one set of marked prints, or strapping prints, showing which of the various options and figures are in use on each switching system as specified in paragraph (x)(3)(i) of this section;

(xvii) Place the battery in service in compliance with the recommendations of the battery manufacturer; and

(xviii) Furnish the owner with a record of the cell voltages and specific gravity readings made at the completion of the installation of the switching system and before it is placed in commercial service.

(3) Installation requirements. (i) All work shall be done in a neat, workmanlike manner. Equipment frames or cabinets shall be correctly located, carefully aligned, anchored and firmly braced. Cables shall be carefully laid with sufficient radius of curvature and protected at corners and bends to ensure against damage from handling or vibration. Exterior cabinet installations for RST's shall be made in a permanent, eye-pleasing manner.

(ii) All multiple and associated wiring shall be continuous, free from crosses, reverses and grounds and shall be correctly wired at all points.

(iii) An inspection shall be made by the owner or its representatives prior to performing operational and performance tests on the equipment. However, this inspection shall be made after all installing operations which might disturb apparatus adjustments have been completed. The inspection shall be of such character and extent as to disclose with reasonable certainty any unsatisfactory condition of apparatus or equipment. During these inspections, or inspections for apparatus adjustments, or soldering, or in testing of equipment, a sufficiently detailed examination shall be made throughout the portion of the equipment within which such condition is observed, or is likely to occur, to disclose the full extent of its existence, where any of the following conditions are observed:

(A) Apparatus or equipment units failing to compare in quantity and code with that specified for the installation;

(B) Apparatus or equipment units damaged or incomplete;

(C) Apparatus or equipment affected by rust, corrosion or marred finish; or

(D) Other adverse conditions resulting from failure to meet generally accepted standards of good workmanship.

(4) Operational test requirements. (i) Operational tests shall be performed on all circuits and circuit components to ensure their proper functioning in accordance with appropriate applicable documents supplied by the bidder.

(ii) A sufficient quantity of overall tests shall be made to ensure proper operation of all specified features.

(iii) A sufficient quantity of locally originating and incoming calls shall be made to prove the switching system can accept and process calls to completion.

(5) Grounding system audit. (i) A grounding system audit shall be performed to ensure that a viable single-point grounding system is in place prior to the time the switching system is placed into full service operation. It is suggested that such an audit be conducted at the time the switching system is ready for turnover to the owner.

(ii) This single-point grounding system audit is to be conducted by authorized representatives of the supplier and owner, and with the RUS general field representative participating at his discretion.

(iii) The single-point grounding system audit is to be conducted using the checklist contained in appendix D of this section.

(iv) Appendix D of this section shall be the principal single-point grounding system audit guideline document. A supplemental checklist may be prepared and provided by the switching system supplier which recognizes unique grounding requirements related to their particular switching system. The scope of this supplier checklist is to be confined to unique and specific switching system requirements only. Acceptable supplier supplemental grounding checklist must have prior approval of and be on file with the Central Office Equipment Branch of the Telecommunications Standards Division of RUS.

(v) It is the responsibility of the central office supplier to ensure that the grounding system evaluation criteria contained in the combination of the appendix D checklist of this section and their optional supplemental checklist adequately fulfill requirements for warranty coverage.

(vi) All deficiencies in the single-point grounding system are to be corrected prior to the switching system being placed into full service operation. Exceptions are permitted only by mutual agreement of the owner and supplier and with written approval of the RUS general field representative.

(vii) The acceptance statement facesheet of the audit checklist in appendix D of this section shall be signed by authorized representatives of the supplier and owner to indicate mutual approval of the single-point grounding system. Copies of all completed grounding system audit documents are to be provided to the supplier, owner and appropriate RUS telephone program regional offices.

(The information and recordkeeping requirements of this section have been approved by the Office of Management and Budget under the control number 0572-0059) Appendix A to § 1755.522—Specification for Digital, Stored Program Controlled Central Office Equipment Detailed Requirements (Host) (Information To Be Supplied by Owner) Telephone Company Name Location Central Office Name (By Location) Town County State ________ Attended ________ Unattended ________ Remotes 1. General

1.1 Notwithstanding the bidder's equipment lists, the equipment and materials furnished by the bidder must meet the requirements of paragraphs (a) through (x), Appendix A and Appendix B of § 1755.522.

1.2 Paragraphs (a) through (x) of § 1755.522 cover the minimum general requirements for digital, stored program controlled central office switching equipment.

1.3 Paragraph (y) of § 1755.522 covers requirements for installation, inspection, and testing when such service is included as part of the contract.

1.4 Appendices A and B of § 1755.522 cover the technical data for application engineering and detailed equipment requirements insofar as they can be established by the owner. These appendices are to be filled in by the owner.

1.5 Appendix C of § 1755.522 covers detailed information on the switching network equipment and the common control equipment, and information as to system reliability and heavy traffic delays as proposed by the bidder. This appendix is to be filled in by the bidder and must be presented with the bid.

1.6 Appendix D of § 1755.522 is the single-point grounding system audit checklist.

2. Numbering Scheme

2.1 This office shall be arranged to serve the following area and office code(s):

If more than one code is to be served, discrimination shall be determined by the following:

Number Translation ____ Separate Trunk Groups ____ Both (Explain in Item 16, Appendix A) ____

2.2 This office shall be arranged to provide EAS service to the following:

Connecting office	Code	Connecting office	Code

2.2.1 Seven digits shall be dialed for all local and EAS calls.

2.3 Additional dialing procedures to be provided include the following:

Feature	Required	Station Paid Toll (Including Coin):		Home Numbering Plan Area (HNPA):		“1” + 7 Digits	______________	“1” + 10 Digits	______________	Other (Explain in Item 16, Appendix A)	______________	Foreign Numbering Plan Area (FNPA):		“1” + 10 Digits	______________	Other (Explain in Item 16, Appendix A)	______________

10XXX Dialing to Interexchange Carriers:

Name	Access code

Feature	Required	Person, Special (Including Coin):		HNPA—“0” + 7 Digits		“0” + 10 Digits		FNPA “0” + 10 Digits		Other (Explain in Item 16, Appendix A)		Directory Assistance:		HNPA Local—411		“1” + 411		HNPA Toll “1” + 555-1212		FNPA Toll “1” + NPA + 555-1212		IDDD:		Operator Serviced 01		Station-Station 011

Other service codes	No. to be dialed	Wire Chief		Repair Service		Business Office		Emergency Calls to 911 Lines		Emergency Calls to 911 Trunks		Time		Weather		100 Test Line		102 Test Line		105 Test Line		Other (Explain in Item 16, Appendix A)

2.4 Assistance calls are answered: (Check appropriate items)

2.4.1 At the operator office in ________________

2.4.1.1 By means of the regular interoffice toll trunks ________

2.4.1.2 By means of the regular interoffice EAS trunks ________

2.4.1.3 By means of a separate special service trunk group ________

2.4.1.4 Locally ________

Explain:

3. Office Clock

3.1 This office is to be slave clock synchronized with another office:

________ Yes ________ No (Explain details in Appendix A, Item 16 if “Yes”.)

3.2 This office is to be a master clock office to provide synchronization timing for other offices:

________ Yes ________ No (Explain details in Appendix A, Item 16 if “Yes”.) 4. Interoffice Trunking Diagram

4.1 A sketch showing relative location of exchanges, RST's, and number of circuits shall be included, also the office and area codes of the direct trunk points. The diagram should indicate whether toll or EAS trunk groups are “High Usage” or “Final.” Alternate routes should be included. Indicate whether the trunk termination is direct digital or analog.

5. Translator Function Chart

Called point	Subscriber dials	First route			Alternate routes			Translator action	Send		Translator action	Send		Deletes	Prefixes		Deletes	Prefixes

6. Line Circuit Requirements (Includes all lines associated with RST's.)

6.1.8 WATS Lines (Give details in Appendix A, Item 16)

Number of Inward WATS Lines ________ Number of Outward WATS Lines ________ 6.1.9 Special Lines Required ________ (Explain in Item 16, Appendix A) 6.1.10 Total Number of Lines Required Host ______ (Incl. DDI Concentrator Lines) RST 1 ______ RST 2 ______ RST 3 ______ Total ______ 6.1.11 Total Director Numbers Required ______ (Including RST's) (see Item 7.1, Appendix A) 6.1.12 Pay Station Type ____________ New ____ Reused ____ (Describe in Item 16, Appendix A) 6.1.13 Line Concentrator 6.1.13.1 Supplied by Owner (see Item 16, Appendix A, for details) ____ Yes ____ No 6.1.13.2 Supplied by Bidder (If “Yes”, attach REA Form 397g, Performance Specification for Line Concentrators) ____ Yes ____ No

6.2. Data on Lines Required Range Extension

6.2.1 Number of non-pay station lines having a loop resistance, including the telephone set, as follows:

No. of lines

1901-3200 ohms

______

3201-3600 ohms

______

6.2.2 Number of pay station lines having loop resistance, excluding the telephone set, greater than:

No. of lines

1200 ohms (For Prepay)

______

1000 ohms (For Semi-Postpay Operation)

______

6.2.3 Range extension equipment is to be provided: 6.2.3.1 Loop Extenders: Total Quantity ______ By Bidder—Quantity ______ By Owner—Quantity ______ (Explain in Item 16, Appendix A) 6.2.3.2 VF Repeaters: Total Quantity ______ By Bidder—Quantity ______ (Bidder must have information on loading and cable size.) By Owner—Quantity ______ (Explain in Item 16, Appendix A) 6.2.3.3 Range extension may be furnished as an extended range line circuit at the option of the supplier. If this option is used, the quantities of loop extenders and VF repeaters will be different from the quantities listed above (see Item 6.1,a, Appendix C). ____ Yes ____ No 7. Traffic Data-Line Originating and Terminating Traffic

7.1 Originating Line Traffic—Estimated per Busy Hour (Includes all Lines Associated With RST's):

	(a) CCS per Main Station	(b) No. of Main Stations	(axb) Total CCS	No. of Lines Required 1	Ind.—Res	__________	__________	__________	__________	Ind.—Bus	__________	__________	__________	__________	Special Lines	__________	__________	__________	__________	Pay Station	__________	__________	__________	__________	Telco Official	__________	__________	__________	__________	Wire Chief	__________	__________	__________	__________	No. Htg. or PBX	__________( 2)	__________( 3)	__________	__________	WATS	__________	__________	__________	__________	Data Service	__________	__________	__________	__________	911 Emerg. Service	__________	__________	__________	__________	Total		__________	__________	__________( 4)			(c)	(d)	(e)

1 See Appendix A, Item 6.1.

2 This figure is the CCS per PBX trunk.

3 This figure is the number of PBX trunks.

4 This is the total number of line equipments required. The number to be provided will be determined by the equipment design of the system of the selected bidder. See Appendix C, Item 3.1.1.2.

7.2 Average Originating CCS per Line per Busy Hour

(d) / (e) = ____ / ____ = ____ CCS/Line This office shall be engineered to handle an initial average originating busy hour traffic of ____ CCS per line. It is anticipated that the average originating busy hour traffic will increase to ____ CCS per line. Originating Traffic Attributed to Host Only ____ CCS/Line 7.3 Terminating Traffic—Estimated CCS per Busy Hour It is assumed that the total CCS for terminating traffic is the same as for originating traffic. Since digital switch networks are on a terminal per line basis, the terminating CCS per line will be the same as the originating CCS per line as shown in Item 7.2, Appendix A. Terminating Traffic Attributed to Host Only ____ CCS/Line 7.4 Percent of Pushbutton Lines ____ 7.5 Anticipated Ultimate Capacity (20 years) 7.5.1 Subscriber Lines Host ________ (Incl. DDI Concentrator Lines) RST 1 ________ RST 2 ________ RST 3 ________ Total ________ 8. Trunk Circuit Requirements

8.1 Interoffice Trunking

8.1.2 Pads for 4-Wire Carrier (7dB and 16dB)

Total Quantity ______ By Bidder Quantity ______ By Owner Quantity ______

Refer to the attached information regarding connecting company trunk circuit drawing numbers and name of manufacturer.

8.2 Switched Traffic Data

8.2.1 Originating Traffic

Type	CCS	H.T. secs.	BHC	No. of digits out-pulsed	Sender sig. mode	Remarks	Toll “0”− 1							Toll “0” + 7 1 2							Toll “0” + 10 1 2							Toll S-S “1” + 7 2							Toll S-S “1” + 10 2							Toll Other							Special Service							Intercept							Intraoffice				XXXXXXX	XXXXXXX		EAS							EAS							EAS							Tandem							Tandem							Tandem							911 Emerg. Service							Total

1 PPCS traffic assumed to be divided 20 percent “0”− and 80 percent “0” + if unknown.

2 Toll calls assumed to be divided two-thirds 7 digits and one-third 10 digits.

Busy Hour Attempts = BHC Total × 1.4 = ____

8.2.2 Terminating Traffic

Type	CCS	H.T. secs.	BHC	No. of digits inpulsed	Receiver sig. mode	Remarks	Toll Compl.							Test & Ver.							Intraoffice							EAS							EAS							EAS							Tandem							Tandem							Tandem							Total

9. Checklist of Features Required

9.1 Alternate Routing

(Explain in Item 16, Appendix A)

9.2 Data Service

(Explain in Item 16, Appendix A)

9.3 This office shall be:

9.3.1 End Office Only

9.3.2 End Office and Intermediate Tandem

(Explain in Item 16, Appendix A)

9.3.3 End Office and Access Tandem

(Explain in Item 16, Appendix A)

9.4 Billing Data

	Trunk group	Send ANI feature group			Store billing data		B	C	D	AMA system	Pollable system	9.4.1 This office only							9.4.2 Trunks from Tributaries							9.4.3 Local Message Detail Recording:

9.5 Pollable Systems

9.5.1 Polling device to be provided on this contract

____ Required ____ Not Required (Provide details in Item 16, Appendix A)

9.5.2 Pollable system to be backed up by tape or disc standby

____ Required ____ Not Required 9.6 AMA Format

9.6.1 Bellcore Format

____ Required ____ Not Required (Provide details in Item 16, Appendix A) 10. Miscellaneous Operating Features 10.1 Busy Verification 10.1.1 By dedicated trunk from toll operator: ____ 10.1.1.1 One-Way, Inward ____ 10.1.1.2 Two-Way (Busy verification inward, intercept outward) ____ 10.1.2 By prefix digit over intertoll trunk ____ (Indicate digit(s) dialed) ____ 10.1.3 Access by Switchman 10.1.3.1 Dedicated Trunk ____ 10.1.3.2 Multiple of Operator Trunk ____ 10.2 Intercept Facilities 10.2.1 Vacant code, disconnected number, and unassigned number intercept shall be: (Check One) By recorded announcement: Without cut-through to operator ____ With cut-through to operator ____ By operator ____ 10.2.2 Changed number intercept shall be: (Check One) By recorded announcement: Without cut-through to operator ____ With cut-through to operator ____ By operator ____ By automatic intercept system (AIS) in distant office ____ 10.2.3 Method of Reaching Operator, if required: Separate trunk group ____ Regular interoffice toll trunks with idle trunk selecting over at least three trunks when three or more toll trunks are equipped ____ 10.2.4 Number of separate intercept trunk circuits ____ 10.3 Line Load Control 10.3.1 Line load control facilities are: ____ Required ____ Not Required (Explain in Item 16, Appendix A) 10.4 Service Observing Facilities 10.4.1 Service observing facilities are: ____ Required ____ Not Required (Explain in Item 16, Appendix A) 10.5 Hotel-Motel Arrangements 10.5.1 Hotel-motel arrangements for operation of message registers at the subscriber's premises are: ____ Required ____ Not Required (Explain in Item 16, Appendix A) 10.5.1.1 How are message registers to be activated? Line Reversal ____ Third Wire ____ Other ____ (Explain in Item 16, Appendix A) 10.6 Nailed-Up Connections ____ Required ____ Not Required (Explain in Item 16, Appendix A) 10.7 Vertical Services: (RST Lines are Included)

	Initially	Ultimate	10.7.1 Call Waiting—No. of Lines	____________	____________	10.7.2 Call Forwarding—No. of Lines	____________	____________	____ Local ____ Remote			(Explain in Item 16, Appendix A)			10.7.3 Abbreviated Dialing No. of Lines	____________	____________	No. of Codes per Line ____ for ____ Lines			No. of Codes per Line ____ for ____ Lines			10.7.4 Three-Way Calling—No. of Lines	____________	____________	CCS Per Line	____________	____________

10.7.5 Other ____ (Explain in Item 16, Appendix A) 11. Maintenance Facility Requirements

11.1 Alarm Signals

11.1.1 Handled locally ____

Explain in Detail:

11.1.2 Transmitted to attended point

11.1.2.1 Via operator office trunks ____

11.1.2.2 Via printout or other display service ____

Explain in Detail:

11.1.2.3 Type of tone to operator

11.1.2.3.1 Distinctive tone (see (i)(2)(ix) of § 1755.522) ____

11.1.2.3.2 Other

Explain in Detail:

11.1.3 Alarm checking signals for carrier and mobile radio systems

11.1.3.1 Minor Alarm

11.1.3.2 Major Alarm

11.1.3.3 Terminals for both

11.2 Trouble Location and Test

11.2.1 Outside plant and stations (check desired items)

11.2.1.1 Subscriber's loop test circuit:

11.2.1.1.1 As part of the maintenance center

11.2.1.1.2 Separately

11.2.1.2 Remote test set (Explain in Item 16, Appendix A)

11.2.1.3 Dial speed test circuit (Explain in Item 16, Appendix A)

11.2.1.4 Pushbutton dialing test circuit

11.2.1.5 Howler (per (o)(2)(iii)(C) of § 1755.522)

11.2.1.6 Hand test sets, number required ____ (Explain in Item 16, Appendix A)

11.3 Transmission Tests

11.3.1 Furnish reference tone

Yes ____ No ____

Frequencies and order in which applied	Time interval for application of each frequency	____ Hz	____ Seconds	____ Hz	____ Seconds	____ Hz	____ Seconds	____ Hz	____ Seconds

11.3.2 Test Lines 11.3.2.1 Test Line 100 ____ 11.3.2.2 Test Line 102 ____ 11.3.2.3 Test Line 104 ____ 11.3.2.4 Test Line 105 ____ (Explain in Item 16, Appendix A) 11.3.2.5 Test Line 107 ____ 11.3.2.6 Remote Office Test Line ____ (Explain in Item 16, Appendix A)

11.4 Line Testing

11.4.1 Automatic line insulation testing

Yes ____ No ____

11.4.2 Owner supplied equipment

Yes ____ No ____

11.4.2.1 Vendor supplied interface only

Yes ____ No ____

If supplied by owner, explain in Item 16, Appendix A, including manufacturer, model, location.

11.5 Remote Control

11.5.1 Remote control of the system shall be provided.

Yes ____ No ____

If required, explain in Item 16, Appendix A, including number, type and location.

12. Power Equipment Requirements (Host Office Only)

12.1 Central Office Battery

12.1.1 A battery reserve of ____ busy hours shall be provided for this office when it reaches ____ lines at the ultimate anticipated traffic rates specified in Item 7.2, Appendix A.

12.1.1.1 The owner will furnish a standby generator, permanently installed in this office, with capacity sufficient to power air conditioning equipment required for cooling of the central office equipment and to maintain an adequate dc supply in the event of a failure of the commercial ac supply.

Yes ____ No ____

12.1.2 Type of battery: (Check One)

Lead Calcium ____ Lead Antimony ____

12.1.3 Voltmeter (portable 3-60-150 volt scale, 1% accuracy) shall be furnished.

Yes ____ No ____

12.1.4 Hydrometer in a hydrometer holder with glass or plastic drop cup shall be furnished.

Yes ____ No ____2112.1.5 Type of battery rack required: (Check One) Two Tier ____ Other ____ Explain:

12.1.6 Special equipment power requirements (carrier, voice frequency repeaters, etc.). Drain in amperes ____

12.1.6.1 Supply all necessary equipment to provide the following 48-volt battery taps:

Number of circuits	Fuse (or circuit breaker) size

12.2 Charging Equipment

12.2.1 Charging equipment shall be provided capable of charging the office battery on a full float basis when the office reaches ____ lines at the ultimate anticipated traffic rates specified in Item 7.2, Appendix A.

12.2.2 Charger input rating shall be:

	3-Phase Connection:	Voltage ____	3-Wire ____	Phase ____	4-Wire ____	Frequency ____	Delta ____				Y ____

12.3 Ringing Equipment

12.3.1 Solid-state ringing equipment in accordance with paragraph (s)(5)(i) of § 1755.522 shall be provided for generating the frequencies specified by check marks in the following table. Ringing generator sets serving the entire office shall each be sized to carry the full office ringing load when the office size reaches ____ lines at the ultimate anticipated traffic rates specified in Item 7.2, Appendix A.

12.3.2 Ringing frequencies to be supplied:

	Frequency in Hz		Maximum No. of telephones	Single Frequency	20			Decimonic	20				30				40				50			Harmonic	16 2/3				25				33 1/3				50			Synchromonic	20				30				42				54

12.3.3 Furnish frequency meter (accurate within 1.3 Hz) and voltmeter (5% accuracy) for ringing measurements (see paragraph (s)(7)(ii) of § 1755.522). Check One:

Panel Mounted ____ Portable ____ Not Required ____

12.4 Power Board

The power panel and associated wiring shall be of ample size to meet the load requirements when this office reaches ____ lines at the ultimate anticipated traffic rates specified in Item 7.2, Appendix A.

13. Distributing Frame Requirements (Host Office Only)

13.1 Total number of outside plant cable pairs to be terminated

13.1.1 Gauge of outside plant cable pairs

13.2 Number of outside plant cable pairs to be protected

13.3 Number of additional protector pair units to be provided on MDF

Explain:

13.4 Main Frame Details

Is present MDF to be reused?

Yes ____ No ____

If “Yes,” Type ____

Reused protectors are:

____ (Mfgr.) ____ (Type)

13.4.1 Number of pairs of arrester units (switching equipment) ____

13.4.2 Number of pairs of gas tube arrester units (special equipment) ____

13.4.2.1 Gas tubes to be:

____ light, ____ medium, ____ heavy, ____ max. duty units

13.4.2.2 Fail shorted/low breakdown failure mode required

Yes ____ No ____

13.4.2.3 Breakdown voltage of gas tube arresters ____

13.4.3 Number of terminated pairs to be grounded ____

13.4.4 Factory assembled tip cable

Yes ____ No ____

13.4.4.1 Tip cable length [if other than 20 feet (610 cm)]

____

13.4.4.2 Tip cable formed

Up ____ Down ____

13.4.5 Pairs per vertical ____

13.4.6 Height of vertical ____ feet ____ inches

14. Building and Floor Plan Information (Host Office Only)

14.1 Equipment is to be installed in an existing building (Attach detailed plan.) ____

14.2 A new building is planned ____

14.2.1 Tentative plan (Note to Engineer: Show sketch without dimensions.)

14.3 Detailed Arrangements

14.3.1 Partition required (to isolate space containing battery, charger, power board, test panel, main distributing frame and subscriber's loop test circuit (wire chief's test desk) from that of the remaining equipment).

Yes ____ No ____

14.3.2 Vestibule required

Yes ____ No ____

14.3.3 Cable entrance

Overhead____ Underground ____

14.3.4 Additional floor space will be required for the following equipment which is being furnished by the owner or by the connecting company:

14.3.5 The office will be arranged for

Overhead Interbay Cabling ____ Underfloor (Computer Room Type) Interbay Cabling ____

14.3.6 Is earthquake bracing required?

Yes ____ No ____

(If “Yes,” explain zone and criteria used for zone in Item 16, Appendix A.)

14.3.7 Office ground will be ____ ohms or less (Refer to Item 4.6.3 of RUS TE&CM 810.)

14.3.8 The office is considered to be in the following category for lightning damage probability based on the Figure 1 map of RUS TE&CM 823 (see paragraph (u)(2) of 1755.522).

____ Very High ____ Higher than Average ____ Average ____ Lower than Average ____ Very Low

14.3.9 The following is additional information regarding operating environment conditions which should be considered in determining system protection requirements (tower in vicinity, high exposure, etc.):

15. Alternate Requests

16. Explanatory Notes (Include a detailed description of any equipment to be reused, or otherwise supplied by the owner, loop extenders, subscriber carrier, VF repeaters, etc.)

Appendix B to 7 Cspan 1755.522—Detailed Information on Remote Switching Terminals (RST's) (Complete One Form For Each RST) 1. Number of Subscriber Lines (These lines included in totals in Item 6, Appendix A).

1.1 Single-Party: ________ Flat Rate ________ Message Rate.

1.2 Semi-Postpay Pay Station ________.

1.3 Prepay Pay Station ________.

1.4 PABX Lines ________ Loop Start________ Ground Start ________ Restricted at Office ________ Other ________

(Describe in Item 12, Appendix B)

1.5 Number of lines to be pushbutton ________________

1.6 911 Emergency Lines ________

1.7 Anticipated ultimate capacity (20-Year) ________

2. Traffic

2.1 Originating traffic per line—CCS/BH: ________ Initial ________ Ultimate.

2.2 Terminating traffic per line—CCS/BH: ________ Initial ________ Ultimate

2.2.1 Terminating will be made equal to originating if it is not known to be different.

3. Subscriber Loop Resistance

3.1 Number of subscriber lines having loop resistance, including the telephone set of:

No. of Lines 1501-1900 Ohms __________ 1901-3200 Ohms ________

3.2 Number of pay station lines having loop resistance, excluding the telephone set, greater than:

No. of Lines 1200 Ohms (For Prepay) ____________ 1000 Ohms (For Semi-Post Pay Operation) __________. 4. Range Extension

4.1 If no standby power is available at the site, loop extenders may be required on 1501 to 1900 ohms loops.

4.2 Loop extenders: Total Quantity __________ By Bidder—Quantity ________ By Owner—Quantity

(Explain in Item 12, Appendix B) 4.3 VF repeaters: Total Quantity __________ By Bidder—Quantity __________ By Owner—Quantity __________. (Explain in Item 12, Appendix B) 5. Power Supply

5.1 Power Board.

5.1.1 The power board and associated wiring shall be of ample size to meet the load requirements when this RST reaches ________ lines at the ultimate anticipated traffic rates specified in Item 2, Appendix B.

5.2 Charger input rating shall be: Voltage __________ Phase __________ Frequency __________

3-Phase Connection: 3-Wire __________ 4-Wire __________ Delta __________ Y__________

5.2.1 Charger shall be capable of charging the RST battery on a full float basis when the RST reaches ________ lines at ultimate traffic rate specified in Item 2, Appendix B.

5.2.2 Charger shall be redundant ________.

5.3 Battery reserve shall be ________ busy hours when the RST reaches ________ lines at the ultimate anticipated traffic specified in Item 2, Appendix B.

5.4 Standby power is available. Yes ______ No ______.

5.5 Special equipment power requirements ________ amps.

5.6 Ringing.

5.6.1 Type of Ringing.

5.6.2 Frequency No.	1.	2.	3.	4.	Frequency (Hz)					Max. No. Phones/Frequency

5.6.3 Wattage to be sized for ________ lines.

5.6.4 Frequency Meter (see Item 12.3.3, Appendix A). Panel Mounted ______ Not Required ______.

6. Emergency Operation

6.1 If path to central office is opened, the RST shall be able to complete calls between subscribers in its own system: Yes ______ No ______

Further requirements should be listed under Item 12, Appendix B.

7. RST Distribution Frame Requirements

7.1 Total number of outside plant cable pairs to be terminated ______.

7.1.1 Gauge of outside plant cable pairs ________.

7.2 Number of outside plant cable pairs to be protected ________.

7.3 Number of additional protector pair units to be provided on MDF ________.

Explain:

7.4 Main Frame Details

7.4.1 Present MDF to be reused Yes______ No______.

If “Yes”, Type ________.

Reused protectors are: ________ (Mspan.) ________ (Type).

7.4.2 Number of pairs of arrester units (switching equipment) ________.

7.4.3 Number of pairs of gas tube arrester units (special equipment) ________.

7.4.3.1 Gas tubes to be: ______ light, ______ medium, ______ heavy, ______ maximum duty units.

7.4.3.2 Fail shorted/low breakdown failure mode required Yes ______ No ______.

7.4.3.3 Breakdown voltage of gas tube arresters ________.

7.4.4 Number of terminated pairs to be grounded ________.

7.4.5 Factory assembled tip cable Yes ______ No ______.

7.4.5.1 Tip cable length [if other than 20 feet (610 cm)] ______.

7.4.5.2 Tip cable formed Up ______ Down ______.

7.4.6 Pairs per vertical ________.

7.4.7 Height of vertical ________ feet ________ inches.

8. Building and Floor Plan Information

8.1 RST to be mounted in building ______.

8.1.1 Earthquake bracing required Yes ______ No ______ (see Item 14.3.6, Appendix A).

8.1.2 Supply building floor plan.

8.2 RST to be mounted in cabinet out of doors ______.

8.2.1 Cabinet to be mounted ______ on pole ______ on ground.

9. Subscriber Line Test

9.1 Remote testing of subscriber lines is required Yes ______ No ______.

9.2 Subscriber loop test set ______.

10. Span Lines to Host Central Office

10.1 To be supplied by Owner ______.

10.2 To be supplied by Bidder ______.

10.2.1 When the bidder is to supply the span lines, an RUS Form 397b, Trunk Carrier Systems, with the applicable parts completed must be attached with a physical layout of the span line.

11. Grounding Considerations

11.1 The RST ground will be ______ ohms or less. (Refer to Item 4.6.3 of RUS TE&CM 810.)

11.2 This RST is considered to be in the following category for lightning damage probability based on the Figure 1 map of RUS TE&CM 823.________ Very High ________ Higher than Average ________ Average ________ Lower than Average ________ Very Low

11.3 The following is additional information regarding operating environment conditions which should be considered in determining system protection requirements (tower in vicinity, high exposure, etc.):

12. Explanatory Notes Appendix C to 7 Cspan 1755.522—Specifications for Digital, Stored Program Controlled Central Office Equipment Detailed Requirements—Bidder Supplied Information Telephone Company Name Location Central Office Name (By Location) Town __________ County __________________ State ______

Attended ______ Unattended ______

1. General

1.1 The equipment and materials furnished by the bidder must meet the requirements of paragraphs (a) through (x), Appendix A, and Appendix B of § 1755.522.

1.2 Paragraphs (a) through (x) of § 1755.522 cover the minimum general requirements for digital, stored program controlled central office switching equipment.

1.3 Paragraph (y) of § 1755.522 covers requirements for installation, inspection, and testing when such service is included as part of the contract.

1.4 Appendices A and B of § 1755.522 cover the technical data for application engineering and detailed equipment requirements insofar as they can be established by the owner. These appendices are to be filled in by the owner.

1.5 Appendix C of § 1755.522 covers detailed information on the switching network equipment and the stored program controlled equipment, and information as to system reliability and heavy traffic delays as proposed by the bidder. This appendix is to be filled in by the bidder and must be presented with the bid.

1.6 Appendix D of § 1755.522 is the single-point grounding system audit checklist.

2. Performance Objectives

2.1 Reliability (see paragraph (b) of § 1755.522).

2.2 Busy Hour Load Capacity and Traffic Delay (see paragraph (e)(10) of § 1755.522. Describe basis for traffic analysis).

3. Equipment Quantities Dependent on System Design

3.1 Switch Frames and Circuits.

3.1.1 Number of Lines.

3.1.1.1 The number of lines to be provided shall include the number required for the termination of subscriber lines, Item 7, Appendix A, plus the number required for routine testing plus any additional to meet the minimum switch increment of the selected system.

3.1.1.2 The number of lines provided for this office will be ______

3.1.2 Number of Ports Used for Trunks

3.1.2.1 The number of trunk ports to be provided shall be based on the trunk quantities required (Item 8, Appendix A) as modified by the minimum increment of the selected system. Provision shall be made for at least 5 percent additional inlet and outlet ports over those required initially. The additional ports shall be used for connecting additional trunks that may be required in the future.

3.1.2.2 The number of trunk ports provided for this office will be ____________

3.1.3 Number of Subscriber Directory Numbers

3.1.3.1 The number of directory numbers provided shall be based on the total directory numbers required (Item 6.1.11, appendix A), as modified by the memory increment of the proposed system.

3.1.3.2 The number of subscriber directory numbers provided for this office will be ____________

4. RST

4.1 Information for RST's must be supplied for each RST to be furnished.

4.2 Number of line terminals for this RST will be ____________ .

4.3 Number of span line terminations to the central office being supplied ____________ .

4.4 If the emergency operation option is required, it will provide the following service when connection to the main office is severed:

4.5 The ac power drain at the remote end will be:

Initial ____________ Ultimate ____________ Voltage: Single-Phase ____________ Three-Phase ____________

4.6 Special environmental requirements for the remote end:

5. Power

5.1 AC Power Drain Watts

Initial ____________ Ultimate ____________

5.2 Heat Dissipation Watts

Provide the initial and ultimate equipment dissipation for each equipment room.

5.2.1 Operating Temperature Range

Minimum ____________ Maximum ____________

5.2.2 Operating Humidity Range

Minimum ____________ Maximum ____________ 6. Additional Information to be Furnished by Bidder

6.1 The bidder shall accompany its bid with the following information:

a. Two copies of the equipment list and the calculations from which the quantities in the equipment list are determined;

b. Two copies of the traffic tables from which the quantities are determined, other than the full availability tables shown in paragraph (p)(1)(i) of § 1755.522;

c. Two copies of detailed switching diagram showing the traffic on each route, the grade of service, the quantity of circuits, and main distributing frames;

d. Block diagram of stored program control and associated maintenance equipment;

e. A prescribed method and criteria for acceptance of the completed central office, which is subject to review;

f. Location of technical assistance service with 24-hour maintenance, and conditions when owner will be charged for access to the service;

g. Calculations showing the method by which ringing machine sizes were derived;

h. Precautions to be taken against static discharge;

i. Details of central office grounding requirements, recognizing local grounding conditions;

j. Details concerning traffic measurement capabilities and formats; and

k. Details concerning AMA features and formats to be provided.

6.2 As a part of the response to the bid, the bidder must also list information concerning the types and quantities of spare parts to be furnished. All units, excluding those units described in paragraph (x)(6)(i)(C) of § 1755.522, must fall into one of the four classes. The information must be in the following format:

Unit No.	Unit name	Quantity of units in the CO's and RST's which are bid				Quantity of spare parts furnished with this bid				Class 1	Class 2	Class 3	Class 4	Class 1	Class 2	Class 3	Class 4

7. Explanatory Notes Appendix D to 7 Cspan 1755.522—Acceptance Checklist—Single-point Grounding System 1. Approval Statement Telephone Company: RUS Borrower Designation: RUS Contract Number: N/A Name: Central Office: Remote: Date of Inspection: Names of Inspectors: Owner Representative Central Office Supplies Consulting Engineer Mutually Approved Exceptions: Grounding System Approval: Name (Owner Representative) Signature Title Date Name (Supplier Representative) Signature Title Date 2. General Survey

2.1 This office is considered to be in the following category for probability of lightning damage based on the Figure 1 map in RUS TE&CM 823 (also refer to paragraph (u)(2) of § 1755.522)

____ Very High ____ Higher than Average ____ Average ____ Lower than Average ____ Very low

2.2 Central office ground field (COGF) to be inspected for proper bonding of conductors to ground rods, etc. COGF to earth grounding reading is ________ ohms. (Refer to RUS TE&CM 802, Appendices C and D, Measurement Techniques.) Is this resistance reading acceptable? (Refer to RUS TE&CM 810, Items 1.6, 4.6.2 and 4.6.3 for protection considerations.)

Acceptable: ____ Yes ____ No Comments:

2.3 Ground connection to be inspected from the master ground bar (MGB) to the central office ground field (COGF) to ensure it is properly sized and installed by most direct route with no sharp bends. (Refer to RUS TE&CM 810, Item 4.3.2 and section 8.1.)

Acceptable: ____ Yes ____ No Comments:

2.4 Building structure grounds (steel rebar in footings, ironwork, etc.) are to be properly bonded and connected to the MGB. (Refer to RUS TE&CM 810, Item 4.3.4.)

Acceptable: ____ Yes ____ No Comments:

2.5 Metallic central office door(s) are to be painted with metallic paint with doorknobs left bare. Door(s) and frames are to be grounded to the building structural ground or the MGB.

Acceptable: ____ Yes ____ No Comments:

2.6 Metallic fences within 6 feet (183 cm) of the exchange building, storage facilities ground field, etc. are to be properly bonded to the COGF outside of the central office building. Handhole enclosure is to be used for the COGF connection to permit inspection and disconnect for earth resistance testing. (Refer to RUS TE&CM 810, Appendix C, Item 4.6.1.)

Acceptable: ____ Yes ____ No Comments:

2.7 Lightning rod systems are to be grounded by a separate dedicated ground field. A bond should be provided between the COGF and the lightning rod ground field. Handhole enclosure is to be used for the COGF connection to permit inspection and disconnect for earth resistance testing. (Refer to RUS TE&CM 810, Item 4.3.2.1.)

Acceptable: ____ Yes ____ No Comments:

2.8 Radio/microwave tower ground grid is to be properly bonded to the COGF by a direct outside connection. Handhole enclosure is to be used for the COGF connection to permit inspection and disconnect for earth resistance testing. (Refer to RUS TE&CM 810, Item 4.3.2 and section 10.)

Acceptable: ____ Yes ____ No Comments:

2.9 If a qualified metallic water system is present, inspect the MGB connecting conductor to ensure that it is properly sized and installed by the most direct route with no sharp bends and that it is clamped solidly on the water pipes. (Refer to RUS TE&CM 810, Item 4.3.3 for details on metallic water system grounding.)

Acceptable: ____ Yes ____ No Comments:

2.10 All power and grounding conductors are to be continuous, end to end, with no splices, size discontinuity or intermediate terminations. If an exception is necessary, unusual care must be taken to assure proper bonding between the two sections. (Refer to RUS TE&CM 810, Appendix C, section 5.)

Acceptable: ____ Yes ____ No Comments:

2.11 All ground conductors should be void of sharp bends along their entire lengths. (Refer to RUS TE&CM 810, Item 8.2.2.)

Acceptable: ____ Yes ____ No Comments:

2.12 Ground conductors should only be placed in nonmetallic conduit. Those routed through metallic conduit require that both ends of the conduit be bonded to the ground conductor. (Refer to RUS TE&CM 810, Item 8.2.4.)

Acceptable: ____ Yes ____ No Comments:

2.13 Ground conductors should not be encircled by metallic clamp. Metallic straps are to be removed and replaced with nonmetallic clamps. (Refer to RUS TE&CM 810, Item 8.2.4.)

Acceptable: ____ Yes ____ No Comments:

2.14 If metallic conduit is used, it is to be insulated from all ironwork.

Acceptable: ____ Yes ____ No Comments:

2.15 Inspect to determine if the required central office supplier electrostatic discharge plates, wrist wraps, antistatic floor mats, etc. are available and properly installed. (Refer to RUS TE&CM 810, Item 12.3.)

Acceptable: ____ Yes ____ No Comments:

2.16 Ground conductors, except green wires, should not be routed close and parallel to other conductors so as to minimize induction on surges into equipment wiring. It is also better not to route these ground conductors through cable racks or troughs, or within the confines of any iron work. (Refer to RUS TE&CM 810, Item 8.2.3.)

Acceptable: ____ Yes ____ No Comments: 3. Master Ground Bar (MGB)

3.1 The designated P, A, N, and I segments of the master ground bar (MGB) should be clearly identified. (Refer to RUS TE&CM 810, Figure 1 for MGB segmentation arrangement.)

Acceptable: ____ Yes ____ No Comments:

3.2 Check for appearance and proper location of following on MGB:

(a) R—Interior radio equipment 1

1 Surge Producer—(P)

(b) C—Cable entrance ground bar 1

(c) M—MDF ground bar 1

(d) G—Standby power equipment frame ground 1

(e) N—Commercial power MGN 2

2 Surge Absorber—(A)

(f) B—Building structure ground 2

(g) L—Central office ground field 2

(h) W—Water pipe system 2

(i) N 1—Battery Return 3

3 Grounds to non-IGZ Equipment—(N)

(j) N 2—Outside IGZ: ____________ 3

(k) N 3—Outside IGZ: ____________ 3

(l) I 1—Ground window bar 4

4 Grounds to IGZ Equipment (GWB's)—(I)

(m) I 2—Ground window bar 4

Acceptable: ____ Yes ____ No Comments:

3.3 All connections to MGB are to be two-hole bolted down copper crimped or compression type terminal lugs. (NOTE: No solder connections are permitted.)

Acceptable: ____ Yes ____ No Comments:

3.4 MGB is to be properly insulated from the mounting surface.

Acceptable: ____ Yes ____ No Comments:

3.5 All connections are to be tight.

Acceptable: ____ Yes ____ No Comments:

3.6 The MGB is to have an anticorrosion coating of the type which enhances conductivity.

Acceptable: ____ Yes ____ No Comments:

3.7 Bar is to be clearly stenciled or legibly labeled “MGB.”

Acceptable: ____ Yes ____ No Comments:

3.8 All ground leads are to be properly sized and labeled as to point of origin. (Refer to RUS TE&CM 810, Item 8.3.1 and section 8.1.)

Acceptable: ____ Yes ____ No

Comments: 4. Ground Window Bar (GWB)

4.1 All equipment grounds that originate inside of an Isolated Ground Zone (IGZ) are to be terminated on the GWB which is preferably located physically inside the IGZ and insulated from its support. (Refer to RUS TE&CM 810, Item 5.1.)

Acceptable: ____ Yes ____ No

Comments:

4.2 Each GWB is to be connected to the MGB by the most direct route with a conductor of 2/0-gauge or coarser, or resistance of less than 0.005 ohms. Parallel conductors for redundancy if required by the supplier. (Refer to RUS TE&CM 810, Item 8.1.2.)

Acceptable: ____ Yes ____ No

Comments:

4.3 The metal framework grounds of only that switching equipment and associated electrical equipment located inside of the IGZ should be connected to the GWB as required by the central office equipment supplier. (Refer to RUS TE&CM 810, Item 5.5.)

Acceptable: ____ Yes ____ No

Comments:

4.4 GWB is to be clearly stenciled or labeled “GWB.”

Acceptable: ____ Yes ____ No

Comments:

4.5 All connections are to be tight.

Acceptable: ____ Yes ____ No

Comments: 5. Isolated Ground Zone (IGZ)

5.1 IGZ areas are to be clearly marked on the floor or in some other easily recognizable manner. (Refer to RUS TE&CM 810, Item 6.1.1)

Acceptable: ____ Yes ____ No

Comments:

5.2 Confirm that all framework, cabinets, etc., within the IGZ are ground connected only to the GWB. (Refer to RUS TE&CM 810, Item 5.5.)

Acceptable: ____ Yes ____ No

Comments:

5.3 All cable racks, ground mats, switching and transmission equipment within the IGZ are to have ground leads only to the GWB. (Refer to RUS TE&CM 810, Item 5.5.2.)

Acceptable: ____ Yes ____ No

Comments:

5.4 Review ac power feed arrangement within the IGZ for acceptable receptacle type and confirm that all green wires are properly connected. (Refer to RUS TE&CM 810, Item 5.5.4.)

Acceptable: ____ Yes ____ No

Comments:

5.5 All ironwork, metallic conduit, and other equipment associated with the switch are to be properly insulated at the IGZ boundary as stipulated by the supplier. (Refer to RUS TE&CM 810, Item 6.2.)

Acceptable: ____ Yes ____ No

Comments:

5.6 With the GWB disconnected from the MGB, the resistance reading of ______ ohms between the GWB and the MGB indicates adequate isolation. (CAUTION: Test is to be conducted only with the approval and under the direction of the central office supplier.)

Acceptable: ____ Yes ____ No

Comments 6. Entrance and Tip Cables

6.1 When neither a cable vault nor a splicing trough exists, the outside plant cable should be brought into the central office and spliced to tip cables with a PVC outer jacket (ALVYN R) or equivalent as close as practical to the cable entrance. (Refer to RUS TE&CM 810, Item 7.3.4.)

Acceptable: ____ Yes ____ No

Comments:

6.2 All outside entrance cables and all tip cable shields are to be separated by at least a 3-inch (7.6 cm) gap between shield ends.

Acceptable: ____ Yes ____ No

Comments:

6.3 All entrance cable shields are to be bonded separately to #6 AWG or larger insulated wire or bonding ribbon and connected to the Cable Entrance Ground Bar (CEGB) by most direct route with minimum bends.

Acceptable: ____ Yes ____ No

Comments:

6.4 Outside plant cable shields are to be connected only to the CEGB, and the tip cable shields are to be connected only to the Main Distributing Frame Bar (MDFB).

Acceptable: ____ Yes ____ No

Comments: 7. Cable Entrance Ground Bar (CEGB)

7.1 The CEGB is to be properly insulated from the mounting surface. (Refer to TE&CM 810, Item 4.2.1.)

Acceptable: ____ Yes ____ No

Comments:

7.2 The CEGB is to be located as close as possible to the physical ends of the entrance cable shields.

Acceptable: ____ Yes ____ No

Comments:

7.3 All connections are to use two-hole bolted down copper crimped or compression type terminal lugs. (NOTE: No solder connections are permitted.)

Acceptable: ____ Yes ____ No

Comments:

7.4 All connections are to be tight.

Acceptable: ____ Yes ____ No

Comments:

7.5 Bar is to be clearly stenciled or legibly labeled “CEGB.”

Acceptable: ____ Yes ____ No

Comments:

7.6 All ground leads are to be properly sized and labeled.

Acceptable: ____ Yes ____ No

Comments:

7.7 The CEGB is to have an anticorrosion coating of the type which enhances conductivity.

Acceptable: ____ Yes ____ No

Comments:

7.8 The CEGB is to be connected to the MGB by a properly sized conductor and by the most direct route. (Refer to RUS TE&CM 810, section 8.1.)

Acceptable: ____ Yes ____ No

Comments: 8. Main Distributing Frame (MDF)

8.1 RUS strongly recommends that MDF protectors be furnished without heat coils. (Refer to RUS TE&CM 810, section 7.6.)

Acceptable: ____ Yes ____ No

Comments:

8.2 Incoming cable pairs terminated on MDF protector assemblies should be protected with protector modules. These modules should contain white coded carbon blocks or orange coded gas tube arrestors that are included in the RUS List of Materials. (Refer to RUS TE&CM 810, Item 7.4)

Acceptable: ____ Yes ____ No

Comments: 7

8.3 All incoming subscriber cable pairs are to be properly terminated at either a protector equipped terminal or connected to ground.

Acceptable: ____ Yes ____ No

Comments

8.4 MDF protector assemblies may be mounted directly on the vertical frame ironwork. Protector assemblies on each vertical are interconnected with each other and the Main Distributing Frame Bar (MDFB) with a #6 copper grounding conductor. Alternative means of connecting to the MDFB are also acceptable which do not rely on the frame ironwork for conducting surge currents to ground. (Refer to RUS TE&CM 810, section 7.)

Acceptable: ____ Yes ____ No

Comments

8.5 Protective “ground connections” should be provided between the MDFB and the frame ironwork for personnel protection regardless of the type of protector assembly used. Protective ground leads should be 14-gauge, less than 12 inches (30.5 cm) in length with paint thoroughly removed at point of connection to the ironwork. (Refer to RUS TE&CM 810, Item 7.1.3.)

Acceptable: ____ Yes ____ No

Comments

8.6 The MDFB should be insulated from the frame ironwork in all cases where it is used as a Master Ground Bar (MGB). (Refer to RUS TE&CM 810, Item 7.1.2.)

Acceptable: ____ Yes ____ No

Comments

8.7 Where the MDFB is used as the MGB in very small offices the protective “ground connections” should be connected on the N section of the bar. The MDF line protector assembly grounds should be connected to the P section of the bar. (Refer to RUS TE&CM 810, Item 7.1.4.)

Acceptable: ____ Yes ____ No

Comments

8.8 The MDFB is to be connected to the MGB by the most direct path with minimum bends and proper conductor size. (Refer to RUS TE&CM 810, Item 8.1.4.)

Acceptable: ____ Yes ____ No

Comments

8.9 The MDFB should be free of all other ground leads when not used as an MGB.

Acceptable: ____ Yes ____ No

Comments

8.10 Alternative arrangements which insulate the line protector assemblies and MDFB from the frame ironwork may require a direct ground connection of the frame ironwork to the MGB for personnel protection. Conductor is properly sized and tightened with paint removal on main frame ironwork at point of connection.

Acceptable: ____ Yes ____ No

Comments 9. Power Service Protection and Grounding

9.1 The ground conductor between the ac power system multigrounded neutral (MGN) at the main ac disconnect panel and the master ground bar (MGB) is to be properly sized and connected. (Refer to RUS TE&CM 810, Items 2.19, 4.3.1 and 8.1.3.)

Acceptable: ____ Yes ____ No Comments:

9.2 If there is a non-MGN ac power system, there is to be a properly sized and connected insulated conductor bond between the power service ground electrode and the MGB. (Refer to RUS TE&CM 810, Item 4.3.1.1.)

Acceptable: ____ Yes ____ No Comments:

9.3 AC conductors including ground conductors serving 120-volt ac electric convenience receptacles and all direct wire peripheral equipment, located in the IGZ, should be sized in accordance with normal “green wire” criteria. (Refer to RUS TE&CM 810, Items 5.5.4, 5.5.5, and 5.5.6.)

Acceptable: ____ Yes ____ No Comments:

9.4 Minimum protection for ac power serving the central office buildings should consist of an RUS accepted secondary arrestor at the service entrance. (Refer to RUS TE&CM 810, section 9.)

Acceptable: ____ Yes ____ No Comments:

9.5 A properly sized conductor for ground bonding between the standby power plant framework (not separately derived) and the MGB is to be provided to equalize framework voltages for personnel safety reasons. (Refer to RUS TE&CM 810, Item 4.2.4.)

Acceptable: ____ Yes ____ No Comments: 10. Miscellaneous

10.1 All non-IGZ equipment frames, relay racks, cable racks and other ironwork are to be properly connected to the MGB. (Refer to TE&CM 810, Item 4.4.)

Acceptable: ____ Yes ____ No Comments:

10.2 Shields on high frequency intra-office cables are to be properly isolated and connected only to an isolation ground bar in the relay rack. All shielded cables entering the IGZ should only be referenced at the IGZ termination point as given by the manufacturer. (Refer to RUS TE&CM 810, Item 7.2.1.2.)

Acceptable: ____ Yes ____ No Comments:

10.3 Isolation ground bars in the relay racks are to be properly connected to the MGB with appropriate sized conductor with no sharp bends.

Acceptable: ____ Yes ____ No Comments:

10.4 All radio equipment cabinet(s) are to be at least 10 feet (305 cm) from the IGZ.

Acceptable: ____ Yes ____ No Comments:

10.5 The metal spare parts cabinet is to be grounded with a #6 AWG or larger insulated wire to non-IGZ cable rack, etc. or directly to the MGB.

Acceptable: ____ Yes ____ No Comments: [58 span 30938, May 28, 1993; 58 span 36252, July 6, 1993, as amended at 60 span 1711, Jan. 5, 1995, 60 span 64312, 64314, Dec. 15, 1995; 69 span 18803, Apr. 9, 2004]