397g RUS Performance Specification for Line Concentrators

Expires: XX/XX/20XX

UNITED STATES DEPARTMENT OF AGRICULTURE
Rural Utilities Service
Bulletin 1753E-004 (Form 397g)

SUBJECT:
TO:

RUS Performance Specification for Line Concentrators

All RUS Telecommunications Borrowers
RUS Telecommunications Staff

EFFECTIVE DATE:
EXPIRATION DATE:
rulemaking

September 28, 1995
Date of change of 7 CFR part 1755.397 by

OFFICE OF PRIMARY INTEREST: Central Office Equipment Branch,
Telecommunications Standards Division
FILING INSTRUCTIONS: Discard REA Bulletin 345-185, REA
Performance Specification for Line Concentrators, REA Form 397g,
dated July 29, 1985, and replace with this bulletin. File with
7 CFR 1755 and is available to RUS staff on RUSNET.
PURPOSE: This specification covers RUS general requirements for
a digital line concentrator system. This specification enables
the line concentrator to operate properly as an integral part of
the switched telephone network when connected to physical or
carrier derived circuits and central offices meeting RUS
specifications and other generally accepted telecommunications
practices.
This bulletin is a "user friendly" reformat of the text codified
in 7 CFR §1755.397 published at 60 FR 44727, dated August 29,
1995. Every effort has been made to ensure the accuracy of this
document. However, in case of discrepancies, the regulation at
7 CFR §1755.397 is the authorized source.

__________________________________
Administrator

__________________________
Date

Bulletin 1753E-004 (Form 397g)
Page 2
TABLE OF CONTENTS
Part I - General Specification
1.
2.
3.
4.
5.

General................................................I-1
Types of Requirements..................................I-2
Reliability............................................I-3
System Type Acceptance Tests...........................I-3
Features Required......................................I-4

6.
6.1
6.2
6.3

Subscriber Lines.......................................I-4
General................................................I-4
Dialing................................................I-4
Ringing................................................I-5

7.

Traffic................................................I-5

8.
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.12
8.13
8.14
8.15
8.16
8.17
8.18
8.19
8.20

Transmission Requirements..............................I-6
General................................................I-6
Telephone transmitter battery supply...................I-6
Impedance - subscriber loops...........................I-6
Battery noise..........................................I-6
Stability..............................................I-6
Return Loss............................................I-6
Longitudinal Balance...................................I-6
60 hz longitudinal current immunity....................I-7
Steady noise...........................................I-8
Impulse noise..........................................I-8
Crosstalk coupling.....................................I-8
Digital error rate.....................................I-8
Quantizing distortion..................................I-8
Overload level.........................................I-8
Gain tracking (linearity)..............................I-8
Frequency response.....................................I-9
Envelope delay distortion..............................I-9
Absolute delay.........................................I-9
Insertion loss.........................................I-9
Detailed requirements for direct digital connections...I-9

9.

Alarms................................................I-10

10.
10.1
10.2
10.3
10.4

Electrical Protection.................................I-10
Surge protection......................................I-10
Dielectric strength...................................I-18
Insulation resistance.................................I-18
Self-protection.......................................I-18

11.
11.1
11.2
11.3
11.4

Miscellaneous.........................................I-18
Interconnect wire.....................................I-18
Wire wrapped terminals................................I-19
Protection against corrosion..........................I-19
Screws and bolts......................................I-19
September 1995

Bulletin 1753E-004 (Form 397g)
Page 3
TABLE OF CONTENTS
11.5
11.6
11.7
11.8
11.9
11.10

Environmental requirements............................I-19
Stenciling............................................I-20
Quantity of equipment bays............................I-20
Radio and television interference.....................I-20
Housing...............................................I-20
Distributing frame....................................I-20

12.
12.1
12.2
12.3
12.4
12.5
12.6
12.7
12.8

Power Equipment.......................................I-21
General...............................................I-21
Operating Voltage.....................................I-21
Batteries.............................................I-21
Charging equipment....................................I-22
Power panel...........................................I-24
Ringing equipment.....................................I-24
Interrupter equipment.................................I-24
Special systems.......................................I-24

13.
13.1
13.2

Fusing requirements ..................................I-24
General...............................................I-24
Fuses.................................................I-25

14.
14.1
14.2

Trouble location and test ............................I-25
Equipment.............................................I-25
Maintenance system....................................I-25

15.
16.

Spare parts...........................................I-25
Drawings and printed material.........................I-25

FIGURES
Figure
Figure
Figure
Figure
Figure
Figure
Figure

1
2
3
4
5
6
7

-

Measuring the Effects of Low Frequency Induction..I-7
Summary of Eletrical Requirements and Tests......I-12
Explanation of Surge Waveshape...................I-13
Current Surge Test...............................I-14
Explanation of Arrester Response Delay Time......I-16
60 Hz Current Surge Test.........................I-17
Charger Noise Test...............................I-23

Part II - Installation and Acceptance
1.
1.1
1.2
1.3
1.4
1.5

Installation and Acceptance...........................II-1
General...............................................II-1
Responsibilities of Owner.............................II-1
Responsibilities of Bidder............................II-3
Information to be Furnished by Bidder.................II-4
Installation Requirements.............................II-5

September 1995

Bulletin 1753E-004 (Form 397g)
Page 4
TABLE OF CONTENTS
1.6
1.7
1.8

Operational Tests.....................................II-6
Acceptance Tests and Data Required....................II-6
Joint Inspection Requirements.........................II-7

Part III - Specification for Line Concentrator Detailed
Equipment Requirements
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

General..............................................III-1
Number of Subscriber Lines...........................III-2
Loop Resistance......................................III-2
Traffic Data.........................................III-3
Type of Ringing......................................III-3
Central Office Equipment Interface...................III-3
Transmission Facilities..............................III-4
Power Equipment Requirements.........................III-5
Remote Terminal......................................III-6
Alternates...........................................III-7
Explanatory Notes....................................III-7

Part IV - Specification For Line Concentrators Detailed
Requirements; Bidder Supplied Information
1.
2.
3.
4.
5.
6.

General..............................................IV-1
Performance Objectives...............................IV-1
Equipment QuantitiesDependent on System Design.......IV-2
Power Requirements...................................IV-2
Temperature and Humidity Limitations.................IV-2
Explanatory Notes....................................IV-3

INDEX:

Specification, Line Concentrator

September 1995

Bulletin 1753E-004 (Form 397g)
Page 5

ABBREVIATIONS
A
AC or ac
ANSI
ASTM
CCS
CFR
CO
COE
CSA
dB
dBm0
DC or dc
DP
DS1
ERL
Hz
IEEE
LC
MDF
MF
PC
REA
rms
RUS
SRL
V
VF
øC
øF

Ampere
Alternating Current
American National Standards Institute
American Society for Testing Materials
Centum (hundred) Call Seconds
Code of Federal Regulations
Central Office
Central Office Equipment
Carrier Serving Area
Decibel
Decibel Metallic Referenced to Zero
Direct Current
Dial Pulse
Digital Signal Level 1 (1.544 Mb/s)
Echo Return Loss
Hertz
Institute of Electrical and Electronic Engineers
Line Concentrator
Main Distributing Frame
Multifrequency
Printed Circuit
Rural Electrification Administration
Root Mean Square
Rural Utilities Service
Singing Return Loss
Volts
Voice Frequency
Degree Centigrade
Degree Fahrenheit

September 1995

Bulletin 1753E-004 (Form 397g)
Page 6
BULLETIN TO CFR PARAGRAPH NUMBER CROSS-REFERENCE
PART I

GENERAL SPECIFICATION

1753E-004

1755.397

1753E-004

1755.397

1.
1.1
1.1.1
1.1.2
1.1.3
1.2
1.3
1.3.1
1.4
1.5
1.5.1
1.5.2
1.5.3
1.6
1.7
1.7.1
1.8
1.8.1

(a)
(a)(1)
(a)(1)(i)
(a)(1)(ii)
(a)(1)(iii)
(a)(2)
(a)(3)
(a)(3)(i)
(a)(4)
(a)(5)
(a)(5)(i)
(a)(5)(ii)
(a)(5)(iii)
(a)(6)
(a)(7)
(a)(7)(i)
(a)(8)
(a)(8(i)

6.3
6.3.1
6.3.2
6.3.3
7.
7.1
7.1.1
7.1.2
7.2
7.3

(f)(3)
(f)(3)(i)
(f)(3)(ii)
(f)(3)(iii)
(g)
(g)(1)
(g)(1)(i)
(g)(1)(ii)
(g)(2)
(g)(3)

2.
2.1
2.2
2.3
2.4
2.5
2.6
2.7

(b)
(b)(1)
(b)(2)
(b)(3)
(b)(4)
(b)(5)
(b)(6)
(b)(7)

3.
3.1
3.2

(c)
(c)(1)
(c)(2)

4.
4.1

(d)
(d)(1)

5.
5.1

(e)
(e)(1)

6.
6.1
6.1.1
6.1.2
6.2
6.2.1
6.2.2
6.2.3

(f)
(f)(1)
(f)(1)(i)
(f)(1)(ii)
(f)(2)
(f)(2)(i)
(f)(2)(ii)
(f)(2)(iii)

8.
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.12
8.13
8.13.1
8.13.2
8.14
8.15
8.16
8.17
8.18
8.19
8.20
8.20.1
8.20.2
8.20.3
8.20.4
8.20.4.1
8.20.4.2
8.20.4.3

(h)
(h)(1)
(h)(2)
(h)(3)
(h)(4)
(h)(5)
(h)(6)
(h)(7)
(h)(8)
(h)(9)
(h)(10)
(h)(11)
(h)(12)
(h)(13)
(h)(13)(i)
(h)(13)(ii)
(h)(14)
(h)(15)
(h)(16)
(h)(17)
(h)(18)
(h)(19)
(h)(20)
(h)(20)(i)
(h)(20)(ii)
(h)(20)(iii)
(h)(20)(iv)
(h)(20)(iv)(A)
(h)(20)(iv)(B)
(h)(20)(iv)(C)

9.
9.1

(i)
(i)(1)

September 1995

Bulletin 1753E-004 (Form 397g)
Page 7
1753E-004

1755.397

1753E-004

10.
10.1
10.1.1
10.1.2
10.1.3
10.1.3.1
10.1.3.2
10.1.3.3
10.1.3.4
10.1.3.5
10.1.4
10.1.4.1
10.1.4.2
10.1.4.3
10.1.4.4
10.1.4.5
10.1.5
10.1.6
10.1.6.1
10.1.6.2
10.1.6.3
10.1.6.4
10.2
10.2.1
10.2.2
10.3
10.4
10.4.1
10.4.2
10.4.3

(j)
(j)(1)
(j)(1)(i)
(j)(1)(ii)
(j)(1)(iii)
(j)(1)(iii)(A)
(j)(1)(iii)(B)
(j)(1)(iii)(C)
(j)(1)(iii)(D)
(j)(1)(iii)(E)
(j)(1)(iv)
(j)(1)(iv)(A)
(j)(1)(iv)(B)
(j)(1)(iv)(C)
(j)(1)(iv)(D)
(j)(1)(iv)(E)
(j)(1)(v)
(j)(1)(vi)
(j)(1)(vi)(A)
(j)(1)(vi)(B)
(j)(1)(vi)(C)
(j)(1)(vi)(D)
(j)(2)
(j)(2)(i)
(j)(2)(ii)
(j)(3)
(j)(4)
(j)(4)(i)
(j)(4)(ii)
(j)(4)(iii)

11.10
11.10.1
11.10.2
11.10.3
11.10.4
11.10.5
11.10.6
11.10.7
11.10.8

(k)(10)
(k)(10)(i)
(k)(10)(ii)
(k)(10)(iii)
(k)(10)(iv)
(k)(10)(v)
(k)(10)(vi)
(k)(10)(vii)
(k)(10)(viii)

11.
11.1
11.2
11.2.1
11.2.2
11.2.3
11.2.4
11.3
11.4
11.5
11.5.1
11.5.2
11.5.2.1
11.5.2.2
11.6
11.7
11.8
11.9
11.9.1

(k)
(k)(1)
(k)(2)
(k)(2)(i)
(k)(2)(ii)
(k)(2)(iii)
(k)(2)(iv)
(k)(3)
(k)(4)
(k)(5)
(k)(5)(i)
(k)(5)(ii)
(k)(5)(ii)(A)
(k)(5)(ii)(B)
(k)(6)
(k)(7)
(k)(8)
(k)(9)
(k)(9)(i)

12.
12.1
12.2
12.2.1
12.2.2
12.2.3
12.3
12.3.1
12.3.2
12.3.3
12.3.4
12.4
12.4.1
12.4.2
12.4.3
12.4.4
12.4.5
12.4.6
12.4.7
12.5
12.5.1
12.5.2
12.5.3
12.6
12.7
12.8

(l)
(l)(1)
(l)(2)
(l)(2)(i)
(l)(2)(ii)
(l)(2)(iii)
(l)(3)
(l)(3)(i)
(l)(3)(ii)
(l)(3)(iii)
(l)(3)(iv)
(l)(4)
(l)(4)(i)
(l)(4)(ii)
(l)(4)(iii)
(l)(4)(iv)
(l)(4)(v)
(l)(4)(vi)
(l)(4)(vii)
(l)(5)
(l)(5)(i)
(l)(5)(ii)
(l)(5)(iii)
(l)(6)
(l)(7)
(l)(8)

13.
13.1
13.1.1
13.1.2
13.2

(m)
(m)(1)
(m)(1)(i)
(m)(1)(ii)
(m)(2)

14.
14.1
14.1.1
14.1.2
14.2
14.2.1
14.2.2

(n)
(n)(1)
(n)(1)(i)
(n)(1)(i)
(n)(2)
(n)(2)(i)
(n)(2)(ii)

September 1995

1755.397

Bulletin 1753E-004 (Form 397g)
Page 8
1753E-004

1755.397

1753E-004

1755.397

15.
15.1

(o)
(o)(1)

16.
16.1
16.2
16.2.1
16.2.2
16.2.3
16.2.4

(p)
(p)(1)
(p)(2)
(p)(2)(i)
(p)(2)(ii)
(p)(2)(iii)
(p)(2)(iv)

16.3
16.3.1
16.3.2
16.3.3
16.3.4
16.3.5
16.3.6
16.3.7
16.3.8
16.4

(p)(3)
(p)(3)(i)
(p)(3)(ii)
(p)(3)(iii)
(p)(3)(iv)
(p)(3)(v)
(p)(3)(vi)
(p)(3)(vii)
(p)(3)(viii)
(p)(4)

BULLETIN TO CFR PARAGRAPH NUMBER CROSS-REFERENCE
PART II

INSTALLATION

1753E-004

1755.397

1753E-004

1755.397

1.
1.1
1.2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.2.7
1.2.8
1.2.9
1.2.10
1.2.11
1.2.12
1.2.13
1.2.14
1.2.15
1.2.16
1.2.17
1.2.18
1.2.19
1.2.20
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.8

(q)
(q)(1)
(q)(2)
(q)(2)(i)
(q)(2)(ii)
(q)(2)(iii)
(q)(2)(iv)
(q)(2)(v)
(q)(2)(vi)
(q)(2)(vii)
(q)(2)(viii)
(q)(2)(ix)
(q)(2)(x)
(q)(2)(xi)
(q)(2)(xii)
(q)(2)(xiii)
(q)(2)(xiv)
(q)(2)(xv)
(q)(2)(xvi)
(q)(2)(xvii)
(q)(2)(xviii)
(q)(2)(xix)
(q)(2)(xx)
(q)(3)
(q)(3)(i)
(q)(3)(ii)
(q)(3)(iii)
(q)(3)(iv)
(q)(3)(v)
(q)(3)(vi)
(q)(3)(vii)
(q)(3)(viii)

1.3.9
1.3.10
1.3.11
1.3.12
1.3.13
1.3.14
1.3.15
1.3.16
1.3.17
1.3.18
1.3.19
1.3.20
1.3.21
1.4
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
1.4.7
1.4.8
1.5
1.5.1
1.5.2
1.5.3
1.5.3.1
1.5.3.2
1.5.3.3
1.5.3.4
1.6
1.6.1

(q)(3)(ix)
(q)(3)(x)
(q)(3)(xi)
(q)(3)(xii)
(q)(3)(xiii)
(q)(3)(xiv)
(q)(3)(xv)
(q)(3)(xvi)
(q)(3)(xvii)
(q)(3)(xviii)
(q)(3)(xix)
(q)(3)(xx)
(q)(3)(xxi)
(q)(4)
(q)(4)(i)
(q)(4)(ii)
(q)(4)(iii)
(q)(4)(iv)
(q)(4)(v)
(q)(4)(vi)
(q)(4)(vii)
(q)(4)(viii)
(q)(5)
(q)(5)(i)
(q)(5)(ii)
(q)(5)(iii)
(q)(5)(iii)(A)
(q)(5)(iii)(B)
(q)(5)(iii)(C)
(q)(5)(iii)(D)
(q)(6)
(q)(6)(i)

September 1995

Bulletin 1753E-004 (Form 397g)
Page I-9
1753E-004

1755.397

1.6.2
1.6.3
1.6.4
1.6.5
1.7
1.7.1
1.7.1.1
1.7.1.2
1.7.1.3

(q)(6)(ii)
(q)(6)(iii)
(q)(6)(iv)
(q)(6)(v)
(q)(7)
(q)(7)(i)
(q)(7)(i)(A)
(q)(7)(i)(B)
(q)(7)(i)(C)

1753E-004

1755.397

1.7.1.4
1.7.2
1.7.3
1.8
1.8.1
1.8.1.1
1.8.1.2
1.8.1.3
1.8.2

(q)(7)(i)(D)
(q)(7)(ii)
(q)(7)(iii)
(q)(8)
(q)(8)(i)
(q)(8)(i)(A)
(q)(8)(i)(B)
(q)(8)(i)(C)
(q)(8)(ii)

Parts III and IV of Bulletin 1753E-004 and Appendices A and B of
7 CFR 1755.397 are numbered identically.

September 1995

Bulletin 1753E-004 (Form 397g)
Page I-1
PART I
General Specification
1.

GENERAL

1.1 This bulletin 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:
1.1.1 Terminating subscriber lines at a location remote from the
serving central office;
1.1.2 Concentrating the subscriber lines over a few transmission
and supervisory paths to the serving central office; and
1.1.3 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.
1.2 Industry standards, or portions thereof, referred to in this
specification 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 the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington,
DC.
1.3 ANSI standards are available from ANSI Inc., 11 West 42nd
Street, 13th floor, New York, NY 10036, Telephone (212) 6424900.
1.3.1 ANSI Standard S1.4-1983, Specification for Sound Level
Meters, including Amendment S1.4A-1985.
1.4 ASTM Specification B33-91, Standard Specifications for
Tinned Soft or Annealed Copper Wire for Electrical Purposes.
1.5 Bell Communications Research (Bellcore) standards are
available from Bellcore Customer Service, 60 New England Avenue,
Piscataway, NJ 08854, telephone 1-800-521-2673.
1.5.1 TR-TSY-000008, Issue 2, August 1987, Digital Interface
between the SLC 96 Digital Loop Carrier System and a Local
Digital Switch.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-2
1.5.2 Bell Communications Research (Bellcore) document
TRÄTSYÄ000057, Issue 1, April 1987, including Revision 1,
November 1988, Functional Criteria for Digital Loop Carrier
Systems.
1.5.3 Bell Communications Research (Bellcore) Document
TRÄNWTÄ000303, Issue 2, December 1992, including Revision 1,
December 1993, Integrated Digital Loop Carrier System Generic
Requirements, Objectives, and Interface.
1.6 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
1.7 IEEE standards are available from IEEE Service Center, 445
Hoes Lane, P. O. Box 1331, Piscataway, NJ 08854, telephone
1Ä800-521-2673.
1.7.1 IEEE Standard 455-1985, Standard Test Procedure for
Measuring Longitudinal Balance of Telephone Equipment Operating
in the Voice Band.
1.8 RUS standards are available from Publications and Directives
Management Branch, Administrative Services Division, Rural
Utilities Service, Ag Box 1533, South Building, U.S. Department
of Agriculture, Washington, DC 20250-1533.
1.8.1 RUS Bulletin 345-50, PE-60 (Sept 1979), RUS Specification
for Trunk Carrier Systems, is incorporated by reference at 7 CFR
1755.97.
2.

TYPES OF REQUIREMENTS

2.1 Unless otherwise indicated, the requirements listed in this
bulletin are considered to be fixed requirements.
2.2 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 accomodate end-to-end digital transmission.
2.3 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 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

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-3
and a Local Digital Switch; and TR-TSY-000057, Functional
Criteria for Digital Loop Carrier Systems.
2.4 For RUS acceptance consideration of a LC, the manufacturer
must certify and demonstrate that all requirements specified in
this bulletin are available and in compliance with this bulletin
2.5 Certain requirements are included in this bulletin 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.
2.6 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.
2.7 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.
3.

RELIABILITY

3.1 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.
3.2 The line concentrator terminal units shall be designed such
that there will be no more than 4 hours of total outages in 20
years.
4.

SYSTEM TYPE ACCEPTANCE TESTS

4.1 General test results will be required on each system type.
Any system provided in accordance with this bulletin shall be
capable of meeting any requirement in this bulletin on a
spot-check basis.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-4
5.

FEATURES REQUIRED

5.1 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.
6.
6.1

SUBSCRIBER LINES
General

6.1.1 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
bulletin. This bulletin 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.
6.1.2 There should be provisions for such types of lines as
ground start, loop start, regular subscriber, pay stations, etc.
6.2

Dialing

6.2.1 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.
6.2.2 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.
6.2.3 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 6.2.3,
with an allowable variation of ± 1.5 percent:
Low Group Frequencies (Hz)
697
770
852
941

Part I, September 1995

High Group Frequencies (Hz)
1336
1477
1633
1209
1
2
3
Spare
4
5
6
Spare
7
8
9
Spare
*
0
#
Spare

Bulletin 1753E-004 (Form 397g)
Page I-5
6.3

Ringing

6.3.1 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.
6.3.2 When ringing generators are provided in the LC on an
ancillary basis, they shall be selected from RUS Informational
Publication 344-2 "List of Materials Acceptable for Use on
Telecommunications Systems of RUS Borrowers."
6.3.3 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.
7.
7.1

TRAFFIC
General

7.1.1 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.
7.1.2 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 document §1755.522,
(p)(1)(i), RUS General Specification for Digital Stored Program
Controlled Central Office Equipment.
7.2 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."
7.3 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

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-6
means for displaying the information locally (or at a remote
location when available).
8.

TRANSMISSION REQUIREMENTS

8.1 General: Unless otherwise stated, the requirements in
paragraphs 8.2 through 8.20 of this bulletin are specified in
terms of analog measurements made from Main Distributing Frame
(MDF) terminals to MDF terminals excluding cabling loss.
8.2 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.
8.3 Impedance - Subscriber Loops: For the purpose of this
bulletin, 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.
8.4 Battery Noise: Noise across the remote terminal battery at
power panel distribution bus terminals shall not exceed 35 dBrnC
during the specified busy hour.
8.5 Stability: The long-term allowable variation in loss
through the line concentrator system shall be ñ 0.5 dB from the
loss specified by the bidder.
8.6 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
8.7 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.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-7
8.8 60 Hz Longitudinal Current Immunity: The LC 60 Hz
longitudinal current immunity shall be measured in accordance
with Figure 1 of this bulletin. Under test conditions cited on
Figure 1 of this bulletin, the system noise shall be 23 dBrnC or
less.
Figure 1
Measuring the Effects of Low Frequency Induction

Notes:
1.
2.
3.
4.

Wilcom T194C or Equivalent (900 ohm termination, C-message
weighting, hold coil off)
SNC Noise Choke 35 W, or equivalent
Test at 0.020 Adc and 0.070 Adc
2 ± 0.001 microfarad, 150 Vdc

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-8
8.9 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
8.10 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.
8.11 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.
8.12 Digital Error Rate: The digital line concentrator shall
not introduce more than one error in 108 bits averaged over a 5minute period, excluding the least significant bit.
8.13

Quantizing Distortion

8.13.1

The system shall meet the following requirements:
Input Level (dBm0)
1004 or 1020 Hz
0 to -30
-30 to -40
-40 to -45

Minimum Signal to Distortion
With C-Message Weighting
33 dB
27 dB
22 dB

8.13.2 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.
8.14

Overload Level:

The overload level shall be +3 dBm0.

8.15 Gain Tracking (Linearity) shall meet the following
requirements:

1

Input
+3
-37
1004 Hz

Maximum Gain Deviation
Signal Level1
to -37 dBm0
± 0.5 dB
to -50 dBm0
± 1 dB
reference at 0 dBm0.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-9
8.16 Frequency Response (Loss Relative to 1004 Hz) for line-toline (via trunk group or intra-link) connections shall meet the
following requirements:

1
2

Frequency (Hz)
Loss at 0 dBm0 Input1
60
20 dB Min.2
300
-1 to +3 dB
600 to 2400
±1 dB
3400
-1 to +3 dB
(-) means less loss and (+) means more loss
Transmit End

8.17 Envelope Delay Distortion: On any properly established
connection, the envelope delay distortion shall not exceed the
following limits:
Frequency (Hz)
1000 to 2600
800 to 2800
600 to 3000
400 to 3200

Microseconds
190
350
500
700

8.18 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.
8.19 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).
8.20

Detailed Requirements for Direct Digital Connections

8.20.1 This paragraph 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.
8.20.2 The output of a digital-to-digital port shall be Pulse
Code Modulation (PCM), encoded in eight-bit words using the mu255 encoding law and D3 encoding format, and arranged to
interface with a T1 span line.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-10
8.20.3 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.
8.20.4 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:
8.20.4.1 The span line shall be terminated in a central office
as a minimum a DS1 (1.544Mb/s) shall be provided.
8.20.4.2 The digital central office equipment shall be
programmed to support the operation of the digital port with the
line concentrator subscriber terminal.
8.20.4.3 The line concentrator subscriber terminal used with a
direct digital interface shall be interchangeable with the
subscriber terminal used with a central office terminal.
9.

ALARMS

9.1 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.
10.
10.1

ELECTRICAL PROTECTION
Surge Protection

10.1.1 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-toground 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.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-11
10.1.2 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 bulletin, Summary of Electrical
Requirements and Tests, identifies the tests and their
application.
10.1.3 Electrical protection requirements for line concentrator
equipment can be summarized briefly as follows:
10.1.3.1 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
bulletin, 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 bulletin, Current Surge Tests.
10.1.3.2 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.
10.1.3.3 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 tests.

Part I, September 1995

Part I, September 1995
Same
100V/µs
rise decay
to ½ V.
in tube’s
delay time

+3 σ breakdown
of arrester
employed at
100V/µs of
rise

Paths protected by
arresters, such as
gas tubes, with
breakdown dependent
on V. rate of rise.

Arrester
Response
Delay

Same

10x1000 µs

High Impedance Paths
Exposed to Surges

Voltage
Surge

1000V or
+3 σ dc
breakdown of
arrester
employed

2500V or +3 σ
clamping V of
arrester
employed at
10kV/µs

AC Power Service
Connection

AC Power
Service
Surge
Voltage

3 each Polarity at
1 minute intervals
5 each Polarity
at 1 minute
intervals

11 cycles
of 60 Hz
(0.183 Sec.)

10A rms or
Lesser Current
(See Fig. 6)

High or Low Impedance
paths Exposed to
Surges

60 Hz
Current
Carrying

5 each Polarity
at 1 minute
intervals

No. of Applications
& Max. Time Between

1.2x50 µs

10x1000 µs

Surge
Waveshape

500A or Lesser
Current
(See Fig. 5)

Peak Voltage
Or Current

Low Impedance Paths
Exposed to Surges

Application Criteria

Current
Surge

Test

Summary of Electrical Requirements and Tests

Figure 2

Part I, September 1995

Same

All primary
arresters, if
used, must be
removed.

AC arrester,
if used, must
be removed.
Communications
line arresters,
if used, remain
In place

Comments

Bulletin 1753E-004 (Form 397g)
Page I-12

Bulletin 1753E-004 (Form 397g)
Page I-13
Figure 3
Explanation of Surge Waveshape

Surge Waveshape is defined as follows:
Rise Time x Time to Decay to Half Crest Value
(For example, 10 x 1000 æs)
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).

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-14
Figure 4
Current Surge Test

VL
VB
Z100
RP
RS

=
=
=
=
=

Not to exceed 1000V
Charging Voltage
Test Specimen Impedance to be measured at 100 Hz.
Parallel Resistance (Waveshape)
Series Resistance (Current Limiting)

Z100
RS
RP
VB
________________________________________
0
1
2
3
4
5
7.5
10
15
20
25
30
40
50

5
4
3
2
1
0
0
0
0
0
0
0
0
0

Part I, September 1995

∞
∞
∞
∞
∞
∞
15
10
7.5
6.7
6.25
6
5.7
5.5

2500
2500
2500
1670
1250
1000
1000
1000
1000
1000
1000
1000
1000
1000

Bulletin 1753E-004 (Form 397g)
Page I-15
10.1.3.4 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.
10.1.3.5 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 bulletin, Arrester Response Delay Time.
10.1.4 Tests shall be conducted in the following sequence. As
not all tests are required in every application, non-applicable
tests should be omitted:
10.1.4.1

Current Impulse Test;

10.1.4.2

Sixty Hertz (60 Hz) Current Carrying Tests;

10.1.4.3

AC Power Service Impulse Voltage Test;

10.1.4.4

Voltage Impulse Test; and

10.1.4.5

Arrester Response Delay Time Test.

10.1.5 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
bulletin, 60 Hz Current Surge Tests.
10.1.6 Tests shall be applied between each of the following
terminal combinations for all line operating conditions:
10.1.6.1

Line tip to ring;

10.1.6.2

Line ring to ground;

10.1.6.3

Line tip to ground; and

10.1.6.4

Line tip and ring tied together to ground.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-16
Figure 5
Explanation of Arrester Response Delay Time

Note: The delay time is that period of time when the potential
across an arrester exceeds its dc firing level.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-17
Figure 6
60 Hz Current Surge Test

V

- 700 Volts root mean square (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 50Ω longitudinal.)
Z60 Hz
_______
0
10
20
50
Over 50

RS
_____
140
120
100
100
100

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-18
10.2

Dielectric Strength

10.2.1
tests.

Arresters shall be removed for all dielectric strength

10.2.2 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.
10.3 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.
10.4

Self-protection

10.4.1 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.
10.4.2 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.
10.4.3 Every precaution shall be taken to protect
electrostatically sensitive components from damage during
handling. This shall include written instructions and
recommendations.
11.

MISCELLANEOUS

11.1 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

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-19
paragraphs 10.2 and 10.3 of this bulletin at a temperature of
120°F (49°C), and a relative humidity of 90 percent.
11.2 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:
11.2.1

6 turns of 30 gauge;

11.2.2

6 turns of 26 gauge;

11.2.3

6 turns of 24 gauge; or

11.2.4

5 turns of 22 gauge.

11.3 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.
11.4 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.
11.5

Environmental Requirements:

11.5.1 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.
11.5.2 To the extent practicable, the following temperature
range objectives shall be met:
11.5.2.1 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).
11.5.2.2 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
Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-20
equipment (cabinet) exposed to direct sunlight may be
substituted.
11.6 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.
11.7 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.
11.8 Radio
employed by
frequencies
with radio,
11.9

and Television Interference: Measures shall be
the bidders to limit the radiation of radio
generated by the equipment so as not to interfere
television receivers, or other sensitive equipment.

Housing

11.9.1 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.
11.9.2 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.
11.10

Distributing Frame

11.10.1 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.
11.10.2 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.
11.10.3 The current carrying capacity of each arrester and its
associated mounting shall coordinate with a #22 gauge copper
Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-21
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.
11.10.4 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.
11.10.5 Protectors shall have a "dead front" (either insulated
or grounded) where live metal parts are not readily accessible.
11.10.6 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.
11.10.7 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.
11.10.8
12.

Protector makes and types used shall be RUS accepted.

POWER EQUIPMENT

12.1 General: When specified, batteries and charging equipment
shall be supplied for the remote terminal of the line
concentrator.
12.2

Operating Voltage

12.2.1 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.
12.2.2 Where equipment is dc powered, it must operate
satisfactorily over a range of 50 volts ñ 6 volts dc.
12.2.3 Where equipment is ac powered, it must operate
satisfactorily over a range of 120 ñ 10 volts or 220 ñ 10 volts
ac.
12.3

Batteries

12.3.1 Unless otherwise specified by the owner, sealed batteries
shall be supplied for the remote line concentrator terminal.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-22
12.3.2 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.
12.3.3 The batteries shall be sealed when they are mounted in
the cabinet with the concentrator equipment.
12.3.4 When specified by th owner, battery heaters shall be
supplied in a bidder-furnished housing.
12.4

Charging Equipment

12.4.1 One charger capable of carrying the full dc power load of
the remote terminal shall be supplied unless otherwise specified
by the owner.
12.4.2 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.
12.4.3 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.
12.4.4 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
bulletin, Charger Noise Test.
12.4.5 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.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-23
Figure 7
Charger Noise Test

Note (1) The manufacturer may elect to eliminate the capacitor C
from the measurement.
Capacitance C 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 x 100)/25 = 120,000 µF
(2)

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.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-24
12.4.6 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.
12.4.7 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.
12.5

Power panel

12.5.1 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.
12.5.2 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.
12.5.3

The power panel shall be of the "dead front" type.

12.6 Ringing Equipment: The ringing system shall provide
sufficient ringing on a bridged basis over the voltage and
temperature limits of this bulletin 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.
12.7 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.
12.8 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.
13.
13.1

FUSING REQUIREMENTS
General

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-25
13.1.1 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.
13.1.2 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.
13.2 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.
14.
14.1

TROUBLE LOCATION AND TEST
Equipment

14.1.1 Trouble indications in the system may be displayed in the
form of lights on the equipment units or printed circuit boards.
14.1.2 When required, a jack or other connector shall be
provided to connect a fault or trouble recorder (printer or
display).
14.2

Maintenance System

14.2.1 The maintenance system shall monitor and maintain the
system operation without interruption of call processing except
for major failures.
14.2.2 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.
15.

SPARE PARTS

15.1 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.
16.

DRAWINGS AND PRINTED MATERIAL

16.1 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 bulletin to require
system documentation necessary for the repair of individual
circuit boards.
Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page I-26
16.2 Three complete sets of legible drawings shall be provided
for each central office to be accessed. Each set shall include
all of the following:
16.2.1 Drawings of major equipment items such as frames, with
the location of major component items of equipment shown therein.
16.2.2 Wiring diagrams indicating the specific method of wiring
used on each item of equipment and interconnection wiring between
items of equipment;
16.2.3 Maintenace drawings covering each equipment item that
contains replaceable parts, appropriately identifying each part
by name and part number; and
16.2.4 Job drawings including all drawings that are individual
to the particular line concentrator involved such as mainframe,
power equipment, etc.
16.3
16.3.1

The following information shall also be furnished:
A complete index of required drawings;

16.3.2 An explanation of electrical principles of operation of
overall concentrator system;
16.3.3 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;
16.3.4 A sample of each form recommended for use in keeping
records;
16.3.5 The criteria for analyzing results of tests and
determining appropriate corrective action;
16.3.6 A set of general notes on methods of isolating equipment
faults to specific printed circuit cards in the equipment;
16.3.7 A list of typical troubles which might be encountered,
together with general indications as to probable location of each
trouble; and
16.3.8 All special line concentrator system grounding
requirements.
16.4 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.

Part I, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-1
PART II
INSTALLATION AND ACCEPTANCE
1.

INSTALLATION AND ACCEPTANCE

1.1 General: Paragraphs 17.2.1 through 17.3.21 of this bulletin
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.
1.2

Responsibilities of Owner:

The owner shall:

1.2.1 Allow the bidder and its employees free access to the
premises and facilities at all hours during the progress of the
installation;
1.2.2 Provide access to the remote site and any other site for
development work needed during the installation;
1.2.3 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);
1.2.4 Provide heat or air conditioning when required and general
illumination in rooms in which work is to be performed or
materials stored;
1.2.5 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);
1.2.6 Provide the necessary conduit and commercial and dc-ac
inverter output power to the locations shown on the approved
floor plan drawings;
1.2.7 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;
1.2.8 Provide suitable openings or channels and ducts for cables
and conductors from floor to floor and from room to room;
1.2.9 Provide suitable ground leads, as designated by the bidder
(not required when remote terminal is not installed in a
building);
Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-2
1.2.10 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;
1.2.11 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;
1.2.12 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;
1.2.13 Connect outside cable pairs on the distributing frame
(those connected to protectors);
1.2.14 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;
1.2.15 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;
1.2.16 Make prompt inspections as it deems necessary when
notified by the bidder that the equipment, or any part thereof,
is ready for acceptance;
1.2.17 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;
1.2.18 Provide necessary access ports for cable, if underfloor
cabling is selected;
1.2.19 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
1.2.20 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 Part III of this bulletin.

Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-3
1.3

Responsibilities of Bidder:

The bidder shall:

1.3.1 Allow the owner and its representatives access to all
parts of the building at all times;
1.3.2 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);
1.3.3 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;
1.3.4 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;
1.3.5 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;
1.3.6 Not use gasoline, benzene, alcohol, naphtha, carbon
tetrachloride or turpentine for cleaning any part of the
equipment;
1.3.7 Be responsible for delivering the CO and remote terminal
equipment to the sites where they will be needed;
1.3.8 Install the equipment in accordance with the
specifications for the line concentrator;
1.3.9 Have all leads brought out to terminal blocks on the MDF
(or IDF if stated in Part III of this bulletin) and have all
terminal blocks identified and permanently labeled;
1.3.10 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;
1.3.11 Group the cables to separate carrier frequency, voice
frequency, signaling, and power leads;
1.3.12 Make the necessary power and ground connections (location
as shown in Part III of this bulletin) to the purchaser's power
terminals and ground bus unless otherwise stated in Part III of
Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-4
this bulletin (ground wire shall be 6 AWG unless otherwise
stated);
1.3.13 Place the battery in service in compliance with the
recommendations of the battery manufacturer;
1.3.14 Make final charger adjustments using the manufacturer's
recommended procedure;
1.3.15 Run all jumpers, except line and trunk jumpers (those
connected to protectors) unless otherwise specified in
Part
III of this bulletin;
1.3.16 Establish and update all data base memories with
subscriber information as supplied by the owner until an agreed
turnover time;
1.3.17 Give the owner notice of completion of the installation
at least one week prior to completion;
1.3.18 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;
1.3.19 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;
1.3.20 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
1.3.21 Correct promptly all defects for which the bidder is
responsible.
1.4 Information to be Furnished by Bidder: The bidder shall
accompany its bid with the following information:
1.4.1 Two copies of the equipment list and the traffic
calculations from which the quantities in the equipment list are
determined;
1.4.2 Two copies of the traffic tables from which the quantities
are determined, if other than the Erlang B traffic tables;
1.4.3 A block diagram of the line concentrator and associated
maintenance equipment will be provided.

Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-5
1.4.4 A prescribed method and criteria for acceptance of the
completed line concentrator which will be subject to review.
1.4.5 This special grounding requirements including the
recommended configuration, suggested equipment and installation
methods to be used to accomplish them;
1.4.6 The special handling and equipment requirements to avoid
damage resulting from the discharge of static electricity (see
paragraph 10.4.3 of Part I of this bulletin) or mechanical damage
during transit installation and testing;
1.4.7 The location of technical assistance service, its
availability and conditions for owner use and charges for the
service by the bidder; and
1.4.8 The identification of the subscriber loop limits available
beyond the line concentrator.
1.5

Installation Requirements

1.5.1 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.
1.5.2 All multiple and associated wiring shall be continuous,
free from crosses, reverses, and grounds and shall be correctly
wired at all points.
1.5.3 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:
1.5.3.1 Apparatus or equipment units failing to compare in
quantity and type to that specified for the installation;
1.5.3.2

Apparatus or equipment units damaged or incomplete;

1.5.3.3 Apparatus or equipment affected by rust, corrosion or
marred finish; and
Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-6
1.5.3.4 Other adverse conditions resulting from failure to meet
generally accepted standards of good workmanship.
1.6

Operational Tests

1.6.1 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.
1.6.2 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.
1.6.3 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.
1.6.4 Each alarm or signal circuit shall be checked for correct
operation.
1.6.5 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.
1.7

Acceptance Tests and Data Required

1.7.1 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:
1.7.1.1 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;
1.7.1.2 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;
1.7.1.3 A list of all instruments, including accessories, by
manufacturer and type number, used to obtain the data; and

Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page II-7
1.7.1.4 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.
1.7.2 Data in the form of a checklist or other notations shall
be supplied showing the results of the operational tests.
1.7.3 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.
1.8

Joint Inspection Requirements

1.8.1 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.
1.8.1.1 The owner shall review the acceptance test data and
compare it to the requirements of this bulletin.
1.8.1.2 Sample measurements shall be made on all systems
installed under this contract. Test methods should follow
procedures described in Part I of this bulletin.
1.8.1.3 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.
1.8.2 In the event that the measured data or operational tests
show that equipment fails to meet the requirements of this
bulletin, the deficiencies are to be resolved as set forth in
Article II of Form 397, Special Equipment Contract. (Copies are
available from RUS, Ag Box 1533, US Departmnet of Agriculture,
Washington, DC 20250-1533.) 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.

Part II, September 1995

Bulletin 1753E-004 (Form 397g)
Page III-1

PART III
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 Parts I and III of this bulletin.
1.2 Part I of this bulletin covers the minimum general
requirements for line concentrator equipment.
1.3 Part II of this bulletin covers the requirements for
installation, inspection and testing when such service is
included as part of the contract.
1.4 Part III covers the technical data for application
engineering and detailed equipment requirements insofar as they
can be established by the owner. This part shall be filled in by
the owner.
1.5 Part IV of this bulletin covers detailed information on the
line concentrator equipment, information on system reliability
and traffic capacity as proposed by the bidder. This part is to
be filled in by the bidder and must be presented with the bid.
Part III, September 1995

Bulletin 1753E-004 (Form 397g)
Page III-2

2.

NUMBER OF SUBSCRIBER LINES
Equipped

Single-Party
Pay Station (Type:________)
Other (Describe:__________)
Total
3.

Wired Only

________
________
________

__________
__________
__________

________

__________

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)

_______________

_______________________________________________________

Part III, September 1995

Bulletin 1753E-004 (Form 397g)
Page III-3
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 OF 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
6.1.1

COE will be:
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)

______________________________

_____________________________________________________
_____________________________________________________

Part III, September 1995

Bulletin 1753E-004 (Form 397g)
Page III-4

6.3

Mounting rack for line concentrator furnished by:
___

Bidder

___

Owner

(Specify width and height of rack available)
6.4

______
Height

Equipment to be installed in existing building:
___ Yes (Attach detailed plan)

7.

_____
Width

___

No

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

Part III, September 1995

___ Bidder

Bulletin 1753E-004 (Form 397g)
Page III-5
7.1.3.1

Carrier e/w voice terminations
Manufacturer and type

___ Yes

___ No

___________________

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

8.1.2

Other (Describe) _________________________________________

8.1.3

Standby power is available

8.2

___ Yes

___ No

___ Yes

___ No

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.
Part III, September 1995

Bulletin 1753E-004 (Form 397g)
Page III-6

8.2.5

Batteries supplied shall be:
___ Lead Calcium
___ Stabilized Electrolyte

___ Sealed Lead Acid

___ Other (Describe in item 11)
8.2.6
9.

Standby power is available

___ Yes

___ No

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
11)

___ Manhole, environmentally controlled (Describe in Item

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) ___________________________________________
____________________________________________________________

Part III, September 1995

Bulletin 1753E-004 (Form 397g)
Page III-7
10.

ALTERNATES

11.

EXPLANATORY NOTES

Part III, September 1995

Bulletin 1753E-004 (Form 397g)
Page IV-1

PART IV
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 Part I of this bulletin.
1.2 Part I of this bulletin covers the minimum general
requirements for line concentrator equipment.
1.3 Part II of this bulletin covers requirements for
installation, inspection and testing when such service is
included as part of the contract.
1.4 Part III of this bulletin covers the technical data for
application engineering and detailed equipment requirements
insofar as they can be established by the owner. This part is to
be filled in by the owner.
1.5 Part IV covers detailed information on the line concentrator
equipment, information as to system reliability and traffic
capacity as proposed by the bidder. This part shall be filled in
by the bidder and must be presented with the bid.
2.
2.1

PERFORMANCE OBJECTIVES
Reliability (See Part I, paragraph 3)

________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________

Part IV, September 1995

Bulletin 1753E-004 (Form 397g)
Page IV-2
2.2 Busy Hour Load Capacity and Traffic Delay (See Part I,
paragraph 7)
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
3.

EQUIPMENT QUANTITIES DEPENDENT ON SYSTEM DESIGN

3.1 Transmission Facilities between the Central Office and
Remote Terminals
Type
_____________
_____________
_____________
4.
4.1

Quantity Equipped
_________________
_________________
_________________

Quantity Wired Only
___________________
___________________
___________________

POWER REQUIREMENTS
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 bidderfurnished housing ______________________________________
________________________________________________________________
________________________________________________________________
5.
5.1

TEMPERATURE AND HUMIDITY LIMITATIONS
Temperature

Maximum ºF (ºC)
Minimum ºF (ºC)

Central Office
______________
______________

Remote*
_____________
_____________

*Show conditions outside bidder-furnished housing.

Part IV, September 1995

Bulletin 1753E-004 (Form 397g)
Page IV-3

5.2

Relative Humidity

Maximum
Minimum

Central Office
______________
______________

Remote*
_____________
_____________

*Show conditions outside bidder-furnished housing.
6.

EXPLANATORY NOTES

Part IV, September 1995