[Federal Register Volume 60, Number 167 (Tuesday, August 29, 1995)]
[Rules and Regulations]
[Pages 44727-44748]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-21298]

Rules and Regulations
                                                Federal Register

This section of the FEDERAL REGISTER contains regulatory documents 
having general applicability and legal effect, most of which are keyed 
to and codified in the Code of Federal Regulations, which is published 
under 50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by the Superintendent of Documents. 
Prices of new books are listed in the first FEDERAL REGISTER issue of each 


Federal Register / Vol. 60, No. 167 / Tuesday, August 29, 1995 / 
Rules and Regulations

[[Page 44727]]


Rural Utilities Service

7 CFR Part 1755

RUS Performance Specification for Line Concentrators

AGENCY: Rural Utilities Service, USDA.

ACTION: Final rule.


SUMMARY: The Rural Utilities Service formerly the Rural Electrification 
Administration (RUS) hereby amends its regulation on RUS 
Telecommunications Standards and Specifications for Material, Equipment 
and Construction by codifying the RUS bulletin concerning RUS 
Performance Specification for Line Concentrators, RUS form 397g. This 
specification has been incorporated by reference and will be rescinded 
after the effective date of the final rule. The specification updates 
the end product performance requirements brought about through 
technology advancements since this specification was last issued on 
July 29, 1985.

DATES: Effective date. This regulation is effective on September 28, 
    Incorporation by reference. Incorporation by reference of 
publications listed in this final rule is approved by the Director of 
the Federal Register as of September 28, 1995.

FOR FURTHER INFORMATION CONTACT: Mr. John J. Schell, Chief, Central 
Office Equipment Branch, Telecommunications Standards Division, U.S. 
Department of Agriculture, Rural Utilities Service, room 2838-S, AG Box 
1598, Washington, DC 20250-1500. Telephone: 202-720-0671.


Executive Order 12866

    This rule has been determined to be not significant for purposes of 
Executive Order 12866 and therefore has not been reviewed by OMB.

Executive Order 12778

    This rule has been reviewed under Executive Order 12778, Civil 
Justice Reform. This rule:
    (1) Will not preempt any state or local laws, regulations, or 
policies, unless they present an irreconcilable conflict with this 
    (2) Will not have any retroactive effect; and
    (3) Will not require administrative proceedings before any parties 
may file suit challenging the provisions of this rule.

Regulatory Flexibility Act Certification

    RUS has determined that this rule will not have a significant 
economic impact on a substantial number of small entities, as defined 
by the Regulatory Flexibility Act (5 U.S.C. 601 et seq.) the RUS 
programs provide and finance grants and loans to RUS borrowers at 
interest rates and terms that are more favorable than those generally 
available from the private sector. RUS borrowers, as a result of 
obtaining Federal financing, receive economic benefits which ultimately 
offset any direct economic costs associated with complying with RUS 
regulations and requirements.

Information Collection and Recordkeeping Requirements

    In compliance with the Office of Management and Budget (OMB) 
regulations (5 CFR Part 1320) which implements the Paperwork Reduction 
Act of 1980 (44 U.S.C. 3501 et seq.) and section 3504 of that Act, 
information collection and recordkeeping requirements contained in this 
rule have been approved by OMB under control number 0572-0059. Comments 
concerning these requirements should be directed to the Office of 
Information and Regulatory Affairs of OMB, Attention: Desk Officer for 
USDA, Room 10102, NEOB, Washington, DC 20503.

National Environmental Policy Act Certification

    The Administrator has determined that this rule will not 
significantly affect the quality of the human environment as defined by 
the National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.). 
Therefore, this action does not require an environmental impact 
statement or assessment.

Catalog of Federal Domestic Assistance

    The program described by this rule is listed in the Catalog of 
Federal Domestic Assistance Programs under number 10.851, Rural 
Telephone Loans and Loan Guarantees. This catalog is available on a 
subscription basis from the Superintendent of Documents, the United 
States Government Printing Office, Washington, DC 20402.

Executive Order 12372

    This rule is excluded from the scope of Executive Order 12372, 
Intergovernmental Consultation. A Notice of Final Rule entitled 
Department Programs and Activities Excluded from Executive Order 12372 
(50 FR 47034) exempts RUS and RTB loans and loan guarantees, and RTB 
bank loans, to governmental and nongovernmental entities from coverage 
under this Order.


    RUS makes loans and loan guarantees to telephone system to provide 
and improve telecommunications service in rural areas, as authorized by 
the Rural Electrification Act of 1936, as amended, 7 U.S.C. 901 et 
seq., (RE Act). RUS maintains a system of construction standards and 
specifications for materials and equipment. In accordance with the RUS 
loan contract, these standards and specifications apply to facilities 
constructed by RUS telephone borrowers.
    Presently, RUS Bulletin 345-185, RUS Performance Specification for 
Line Concentrators RUS Form 397g, dated July 29, 1985, is incorporated 
by reference at 7 CFR 1755.97. Because of the many improvements in 
technology since the specification was last issued, RUS believes that 
by updating and codifying the revised specification, borrowers will be 
provided with an opportunity to improve and increase subscriber 
services through enhanced system designs brought about through the 
technological advancements in an economical and efficient manner.

General Comments

    Public comments regarding the proposed rule (59 FR 19661, April 25, 
1994) were received from AT&T and Hastad Engineering Company. These 

[[Page 44728]]
comments were taken into consideration in preparing the final rule.
    1. Comment. One commenter stated that the first sentence in 
paragraph (a)(iii) should be modified to read ``* * * without loss of 
individual identity by either physical or electronic means.''
    Response. The intent of this requirement is to ensure that the 
identities of the lines connected to the remote line concentrator 
terminal are known at the central office. RUS feels this paragraph is a 
clear statement of this requirement.
    2. Comment. One commenter stated that ``at a minimum'' should be 
added following ``The concentrator system shall communicate with the 
standard T1 transmission format'' in paragraph (b)(2).
    Response. RUS agrees and this change has been made.
    3. Comment. One commenter stated in the phrase ``0.5 percent per 
month of all equipped cards in all system terminals after 6 months'' in 
paragraph (c)(1) ``system'' should be changed to ``systems.''
    Response. In this context, the word ``system'' refers to the line 
concentrator system. The reliability requirement is meant to be 
applicable to each concentrator system individually.
    4. Comment. One commenter stated that RUS should consider 
specifying a sine wave output for ringing generators in paragraph 
    Response. A sine wave output is one of the requirements for the 
acceptance of ringing generators by RUS. RUS does not feel that it is 
necessary to reiterate this requirement in the line concentrator 
    5. Comment. One commenter stated that consideration should be given 
to providing an upper limit for loop current in paragraph (h)(2).
    Response. The minimum current requirement ensures proper operation 
of the subscriber's station equipment. The maximum current is largely 
dependent upon the design of the line concentrator's line circuit. This 
specification is intended to be an operational rather than a design 
specification and RUS does not feel that a maximum current requirement 
is necessary in that light.
    6. Comment. One commenter stated that the impedance of 900 ohms in 
paragraph (h)(3) is for D66 loaded cables, not non-loaded cable pairs.
    Response. From a hybrid balance standpoint, 900 ohms in series with 
a 2.16 microfarad capacitor is not a very good match for either loaded 
or non-loaded loops. For this reason most switching equipment uses 
hybrid termination networks more closely matching the characteristic 
impedances of the loops. However, as a compromise the 900 ohm 
termination was used in determining transmission requirements stated in 
paragraph (h)(3).
    7. Comment. One commenter stated the requirement for a central 
office repeater and a DS1 bit stream may be a roadblock to the 
technical innovation. The STMP requirements for high bit rate services 
may not be supported by the low bit rate in paragraph (h)(20)(iv)(A).
    Response. RUS agrees and has removed the repeater requirement and 
made the DS1 rate a minimum.
    8. Comment. One commenter suggested two additions in paragraph 
(j)(1)(iii)(A): (1) Require testing of equipment with 100 Hz impedances 
beyond the 50 ohm maximum RUS has proposed, to a new maximum of 100 
ohms, and (2) reduce the current surge test peak to 100 A from the 
required 500 A but require 25 plus and minus surges instead of the plus 
and minus five surges that RUS proposed.
    Response. RUS evaluated the proposal by estimating the relative 
overall power that would be dissipated by the 100 Hz paths under the 
RUS proposal and the commenter's proposal.
    Because this proposal requires additional testing of 100 Hz 
impedance paths beyond the 50 ohms and because the proposer's method of 
testing for overall and single surge power dissipation is less 
demanding on paths less than 5 and 10 ohms and more demanding for 
impedance paths greater than 5 and 10 ohms, respectively, RUS prefers 
to retain the requirement as RUS proposed it.
    9. Comment. One commenter proposed in paragraph (j)(1)(iii)(B) that 
for 100 ohm, 60 Hz, impedance paths, using a 600 volt power supply and 
86 ohm current limiting resistors (rather than the required 700 volt 
power supply and 100 ohm current limiting resistors) would result in 
approximately the same amount of current flow.
    Response. Although not stated, RUS assumes that the commenter is 
suggesting the requirement be changed to allow the different power 
supply voltage and current limiting resistors. In evaluating the 
circuit testing differences, RUS calculated that the commenter's 
proposal would result in 4.2 amps of current while the RUS proposal 
would cause 4.7 amps. Thus, the commenter's proposal results in a 0.5 
amp less current. Although 0.5 amp is not a major reduction (5 percent 
relative to the 10 amp maximum specified in the RUS proposal), it 
nevertheless is a 5-percent reduction.
    The commenter's suggested power supply voltage is also 100 volts 
lower than the RUS specified supply and it will not provide the same 
voltage stress that is contained in the RUS proposal.
    RUS believes the Sixty Hertz Current Carrying test as proposed by 
RUS is necessary to properly test the system.
    10. Comment. One commenter proposed in paragraphs (j)(1)(iii) (D) 
and (E) that the Voltage Impulse Test be modified to allow use of 
another waveshape (both peak and rise and fall times) and that for both 
the Voltage Impulse Test and the Arrester Response Delay Test that RUS 
allow results obtained by other organizations as part of their 
compliance testing to be acceptable for RUS compliance.
    Response. RUS always attempts to accept test results conducted for 
other purposes as supporting data for RUS requirements when the data 
presented is equivalent or more stringent than RUS requirements.
    All five tests are required to be conducted in a specific sequence 
and as quickly as possible; the endeavor is to inflict all stresses, 
one after another, in a very short time period for the total testing.
    Testing conducted for other organizations, most likely, will not 
satisfy the concerns intended for the RUS electrical protection tests. 
In addition to not using the RUS specified waveshapes, tests by other 
organizations usually do not involve all the individual tests in the 
sequence required nor are they completed at the same time in the quick 
time frame required by RUS; results of various types of testing often 
may not be for tests conducted on the exact same test samples. In a 
number of cases, certain tests by other organizations are expected to 
destroy the product to be certain there is no fire or shock hazard. 
Although RUS is certainly interested in knowing of such hazards, the 
purpose of the RUS electrical protection testing is to see whether the 
line concentrator can withstand the specified surges and operate 
without any difficulty following the testing. Since test samples are 
destroyed by these other types of tests, such product evaluations 
cannot be made.
    Because the test results suggested by the commenter are usually 
completed piecemeal and do not provide the overall rigorous test 
withstand concerns that RUS seeks, RUS cannot accept this suggestion to 
allow alternative waveshapes and prefers to retain the waveshape 
proposed in the proposed rule.
    11. Comment. One commenter stated that RUS should provide a 

[[Page 44729]]
requirement for 120/240 volts AC in paragraphs (q)(2)(vii) and 
    Response. RUS agrees and has made this change in paragraphs 
(q)(2)(vii) and (l)(2)(iii).
    12. Comment. One commenter stated that battery heaters as specified 
in (l)(3)(iv) should not be a required item as determined by the 
bidder, but should be available as an option for the purchaser to 
accept or reject.
    Response. RUS agrees and has changed this paragraph to read ``when 
specified by the owner.''
    13. Comment. One commenter stated that since line concentrators are 
often installed by the purchaser, the bidder cannot provide job 
drawings as required in paragraph (p)(2)(iv). The commenter also stated 
that a minimum of three sets of drawings should be supplied for each 
central office involved rather than for each concentrator.
    Response. RUS has added an additional requirement in (p)(2)(v) when 
installation is to be done by the bidder. This requirement states that 
a complete set of drawings shall be provided, such as floor plans, AC 
power access and grounding parameters. RUS has also stated that three 
sets of drawings are required per central office rather than per 
    14. Comment. One commenter stated that an appropriate secondary 
arrestor should be provided in the remote terminal cabinet.
    Response. Paragraph (q)(2)(vii) requires that a secondary arrester 
be provided.
    15. Comment. One commenter stated the specification should include 
a requirement for a remote cabinet ground lug, either on the cabinet's 
outside or mounted in the interior.
    Response. Paragraph (q)(2)(ix) has been changed to include ground 

List of Subjects in 7 CFR Part 1755

    Incorporation by reference, Loan programs--communications, 
Reporting and recordkeeping requirements, Rural areas, Telephone.

    For the reasons set out in the preamble, RUS amends chapter XVII of 
title 7 of the Code of Federal Regulations as set forth below.


    1. The authority citation for part 1755 is revised to read as 

    Authority: 7 U.S.C. 901 et seq., 1921 et seq., 6941 et seq.

Sec. 1755.97  [Amended]

    2. Section 1755.97 is amended by removing the entry RUS Bulletin 
345-185 from the table.
    3. Section 1755.397 is revised to read as follows:

Sec. 1755.397  RUS performance specification for line concentrators.

    (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 Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.
    (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) TR-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 TR-TSY-
000057, Issue 1, April 1987, including Revision 1, November 1988, 
Functional Criteria for Digital Loop Carrier Systems.
    (iii) Bell Communications Research (Bellcore) Document TR-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 
    (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 
    (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 

[[Page 44730]]
Bellcore documents TR-NWT-000303, Integrated Digital Loop Carrier 
System Generic Requirements, Objectives and Interface; TR-TSY-000008, 
Digital Interface between the SLC 96 Digital Loop Carrier System and a 
Local Digital Switch; and TR-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 TR-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 
    (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:

                                                                                 High group frequencies (Hz)    
                        Low group frequencies (Hz)                         -------------------------------------
                                                                             1209    1336    1477       1633    
697.......................................................................       1       2       3  Spare.      
770.......................................................................       4       5       6  Spare.      
852.......................................................................       7       8       9  Spare.      
941.......................................................................       *       0       #  Spare.      

    (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 Sec. 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 

[[Page 44731]]
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 
    (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 
    (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 
    (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:


[[Page 44732]]


[[Page 44733]]

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

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 

                                                             signal to  
            Input level (dBm0) 1004 or 1020 Hz                with C-   
0 to -30.................................................  33 dB        
-30 to -40...............................................  27 dB        
-40 to -45...............................................  22 dB        

    (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 

                   Input signal level\1\                         gain   
+3 to -37 dBm0.............................................  0.5 dB
-37 to -50 dBm0............................................  1 dB 
\1\1004 Hz reference at 0 dBm0.                                         

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

           Frequency (Hz)                  Loss at 0 dBm0 input\1\      
60.................................  20 dB Min.\2\                      
300................................  -1 to +3 dB                        
600 to 2400........................  +1 dB                              
3400...............................  -1 to +3 dB                        
\1\(-) means less loss and (+) means more loss.                         
\2\Transmit End.                                                        

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

                      Frequency (Hz)                        Microseconds
1000 to 2600..............................................         190  
800 to 2800...............................................         350  
600 to 3000...............................................         500  
400 to 3200...............................................         700  

    (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 Sec. 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 
    (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. 

[[Page 44734]]

    (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:

                             Figure 2.--Summary of Electrical Requirements and Tests                            
                                                                                Number of                       
                      Application      Peak voltage or                       applications and                   
       Test             criteria           current        Surge waveshape      maximum time         Comments    
Current surge....  Low impedance      500A or lesser     10 x 1000 s.               at 1 minute                        
                    surges.            fig. 4).                              intervals.                         
60 Hz current      High or low        10A rms or lesser  11 Cycles of 60    3 each at 1        None.            
 carrying.          impedance paths    current (see       Hz (0.183 Sec.).   minute intervals.                  
                    exposed to         fig. 6).                                                                 
AC Power service   AC power service   2500V or +3        1.2 x 50           m>s.               at 1 minute        used, must be   
                                       clamping V of                         intervals.         removed.        
                                       arrester                                                 Communications  
                                       employed at 10kV/                                        line arresters, 
                                       s.                                              if used, remain 
                                                                                                in place.       
Voltage surge....  High impedance     1000V or +3        10 x 1000  dc       m>s.               at 1 minute        arresters, if   
                    surges.            breakdown of                          intervals.         used, must be   
                                       arrester                                                 removed.        
Arrester response  Paths protected    +3        100V/s    5 each polarity    All primary      
 delay.             by arresters,      breakdown of       rise decay to \1/  at 1 minute        arrestors, if   
                    such as gas        arrester           2\ V. in tube's    intervals.         used, must be   
                    tubes, with        employed at 100V/  delay time.                           removed.        
                    breakdown          s of                                                            
                    dependent on V.    rise.                                                                    
                    rate of rise.                                                                               

    (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 x 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:


[[Page 44735]]

[[Page 44736]]


[[Page 44737]]

    (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 x 50 microsecond waveshape with a crest voltage of 
2500 V. Communications line protectors may be left in place for these 
    (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 x 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:


[[Page 44738]]


[[Page 44739]]

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


[[Page 44740]]


[[Page 44741]]

    (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  deg.F 
(20  deg.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 deg.F (49 deg.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  deg.F to 120  deg.F (0  deg.C to 49 
deg.C) and at 80 percent relative humidity between 50  deg.F and 100 
deg.F (10  deg.C and 38  deg.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  deg.F to 140  deg.F 
(-40  deg.C to 60  deg.C) and at 95 percent relative humidity between 
50  deg.F to 100  deg.F (10  deg.C to 38  deg.C). As an alternative to 
the (60  deg.C) requirement, a maximum ambient temperature of 120 
deg.F (49  deg.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 
    (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 

[[Page 44742]]
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 12010 volts or 22010 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:


[[Page 44743]]


[[Page 44744]]

    (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 
    (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 
    (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 
    (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 
    (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 
    (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 
    (iii) Maintenace 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 
    (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 

[[Page 44745]]

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

[[Page 44746]]
    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 
    (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 
    (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 
    (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 
    (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 repeaters, and fault 
locating circuits.
    (ii) In the event that the measured data or operational tests show 
that equipment fails to meet the requirements 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 (OMB) under the 
control number 0572-0059.)

Appendix A to Sec. 1755.397--Specification for Line Concentrator 
Detailed Equipment Requirements

(Information To Be Supplied by Owner)

Telephone Company (Owner)


Number of LC's Required: ________
Line Concentrator Locations:

                                                   No. of      Central  
                   Location                        Lines        Office  
                                                ...........  ...........
                                                ...........  ...........
                                                ...........  ...........
                                                ...........  ...........

[[Page 44747]]

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    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 

                                                                No. of  
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  
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 

________ 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 ________


           5.1  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





    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)



(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)



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

    7.1.3  Terminal equipment for transmission facility to be 
supplied by:


________Bidder  Carrier e/w voice terminations ________ Yes ________ No

Manufacturer and type--------------------------------------------------
Central office voice terminations Equipped ________, Wired Only 
________  Digital span line (DS1) supplied by



Manufacturer and Type--------------------------------------------------  Number of repeaters (per span line) ________  Diverse (alternate) span line routing required

________Yes (Describe in Item 11) ________No  Span line terminations only ________Yes ________No  Span line power required (CO and Remote Terminals) 
________Yes ________No  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.) 

[[Page 44748]]

    9.3  Other (Describe)


10. Alternates

11. Explanatory Notes
Appendix B to Sec. 1755.397--Specification for Line Concentrators 
Detailed Requirements; Bidder Supplied Information

Telephone Company (Owner)



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

                                                  Quantity     Quantity 
                     Type                         equipped    wired only
                                                ...........  ...........
                                                ...........  ...........
                                                ...........  ...........

4. Power Requirements

4.1  Central Office Terminal


Current Drain (Amps) Normal ________, Peak ________

Fuse Qty ________, Size ________, Type ________

Heat Dissipation (BTU/Hr.) ________

4.2  Remote Terminal

AC or DC---------------------------------------------------------------


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

                                                   office      Remote*  
Maximum  deg.F ( deg.C).......................  ...........  ...........
Minimum  deg.F ( deg.C).......................  ...........  ...........

5.2  Relative Humidity

                                                   office      Remote*  
Maximum.......................................  ...........  ...........
Minimum.......................................  ...........  ...........
*Show conditions outside bidder-furnished housing.                      

6. Explanatory Notes

Dated: August 21, 1995.
Jill Long,
Under Secretary, Rural Economic and Community Development.
[FR Doc. 95-21298 Filed 8-28-95; 8:45 am]