UNITED STATES DEPARTMENT OF AGRICULTURE

Rural Utilities Service

**Bulletin 1753E-004 (Form 397g)**

**SUBJECT:** RUS Performance Specification for Line Concentrators

**TO:** All RUS Telecommunications Borrowers

RUS Telecommunications Staff

**EFFECTIVE DATE:** September 28, 1995

**EXPIRATION DATE:** Date of change of 7 CFR part 1755.397 by rulemaking

**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

**TABLE OF CONTENTS**

Part I - General Specification

1\.
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-1

2\. Types of
Requirements\...\...\...\...\...\...\...\...\...\...\....I-2

3\.
Reliability\...\...\...\...\...\...\...\...\...\...\...\...\...\.....I-3

4\. System Type Acceptance Tests\...\...\...\...\...\...\...\...\...I-3

5\. Features
Required\...\...\...\...\...\...\...\...\...\...\...\.....I-4

6\. Subscriber
Lines\...\...\...\...\...\...\...\...\...\...\...\...\...I-4

6.1
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-4

6.2
Dialing\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-4

6.3
Ringing\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-5

7\.
Traffic\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-5

8\. Transmission Requirements\...\...\...\...\...\...\...\...\...\...I-6

8.1
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-6

8.2 Telephone transmitter battery supply\...\...\...\...\...\....I-6

8.3 Impedance - subscriber loops\...\...\...\...\...\...\...\...\...I-6

8.4 Battery
noise\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-6

8.5
Stability\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....I-6

8.6 Return
Loss\...\...\...\...\...\...\...\...\...\...\...\...\...\.....I-6

8.7 Longitudinal
Balance\...\...\...\...\...\...\...\...\...\...\.....I-6

8.8 60 hz longitudinal current immunity\...\...\...\...\...\.....I-7

8.9 Steady
noise\...\...\...\...\...\...\...\...\...\...\...\...\...\....I-8

8.10 Impulse
noise\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-8

8.11 Crosstalk
coupling\...\...\...\...\...\...\...\...\...\...\...\....I-8

8.12 Digital error
rate\...\...\...\...\...\...\...\...\...\...\...\....I-8

8.13 Quantizing
distortion\...\...\...\...\...\...\...\...\...\...\....I-8

8.14 Overload
level\...\...\...\...\...\...\...\...\...\...\...\...\.....I-8

8.15 Gain tracking
(linearity)\...\...\...\...\...\...\...\...\...\...I-8

8.16 Frequency
response\...\...\...\...\...\...\...\...\...\...\...\....I-9

8.17 Envelope delay
distortion\...\...\...\...\...\...\...\...\...\...I-9

8.18 Absolute
delay\...\...\...\...\...\...\...\...\...\...\...\...\.....I-9

8.19 Insertion
loss\...\...\...\...\...\...\...\...\...\...\...\...\.....I-9

8.20 Detailed requirements for direct digital connections\...I-9

9\.
Alarms\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-10

10\. Electrical
Protection\...\...\...\...\...\...\...\...\...\...\...I-10

10.1 Surge
protection\...\...\...\...\...\...\...\...\...\...\...\.....I-10

10.2 Dielectric
strength\...\...\...\...\...\...\...\...\...\...\.....I-18

10.3 Insulation
resistance\...\...\...\...\...\...\...\...\...\...\...I-18

10.4
Self-protection\...\...\...\...\...\...\...\...\...\...\...\...\...I-18

11\.
Miscellaneous\...\...\...\...\...\...\...\...\...\...\...\...\.....I-18

11.1 Interconnect
wire\...\...\...\...\...\...\...\...\...\...\...\....I-18

11.2 Wire wrapped
terminals\...\...\...\...\...\...\...\...\...\.....I-19

11.3 Protection against corrosion\...\...\...\...\...\...\...\.....I-19

11.4 Screws and
bolts\...\...\...\...\...\...\...\...\...\...\...\.....I-19

**TABLE OF CONTENTS**

11.5 Environmental requirements\...\...\...\...\...\...\...\...\....I-19

11.6
Stenciling\...\...\...\...\...\...\...\...\...\...\...\...\...\.....I-20

11.7 Quantity of equipment bays\...\...\...\...\...\...\...\...\....I-20

11.8 Radio and television interference\...\...\...\...\...\...\...I-20

11.9
Housing\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....I-20

11.10 Distributing
frame\...\...\...\...\...\...\...\...\...\...\...\...I-20

12\. Power
Equipment\...\...\...\...\...\...\...\...\...\...\...\...\...I-21

12.1
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....I-21

12.2 Operating
Voltage\...\...\...\...\...\...\...\...\...\...\...\....I-21

12.3
Batteries\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-21

12.4 Charging
equipment\...\...\...\...\...\...\...\...\...\...\...\...I-22

12.5 Power
panel\...\...\...\...\...\...\...\...\...\...\...\...\...\....I-24

12.6 Ringing
equipment\...\...\...\...\...\...\...\...\...\...\...\....I-24

12.7 Interrupter
equipment\...\...\...\...\...\...\...\...\...\...\...I-24

12.8 Special
systems\...\...\...\...\...\...\...\...\...\...\...\...\...I-24

13\. Fusing requirements
\...\...\...\...\...\...\...\...\...\...\....I-24

13.1
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....I-24

13.2
Fuses\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....I-25

14\. Trouble location and test \...\...\...\...\...\...\...\...\....I-25

14.1
Equipment\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...I-25

14.2 Maintenance
system\...\...\...\...\...\...\...\...\...\...\...\...I-25

15\. Spare
parts\...\...\...\...\...\...\...\...\...\...\...\...\...\....I-25

16\. Drawings and printed material\...\...\...\...\...\...\...\....I-25

FIGURES

Figure 1 - Measuring the Effects of Low Frequency Induction..I-7

Figure 2 - Summary of Eletrical Requirements and Tests\...\...I-12

Figure 3 - Explanation of Surge Waveshape\...\...\...\...\...\....I-13

Figure 4 - Current Surge
Test\...\...\...\...\...\...\...\...\...\....I-14

Figure 5 - Explanation of Arrester Response Delay Time\...\...I-16

Figure 6 - 60 Hz Current Surge Test\...\...\...\...\...\...\...\....I-17

Figure 7 - Charger Noise
Test\...\...\...\...\...\...\...\...\...\....I-23

Part II - Installation and Acceptance

1\. Installation and Acceptance\...\...\...\...\...\...\...\...\...II-1

1.1
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....II-1

1.2 Responsibilities of Owner\...\...\...\...\...\...\...\...\.....II-1

1.3 Responsibilities of Bidder\...\...\...\...\...\...\...\...\....II-3

1.4 Information to be Furnished by Bidder\...\...\...\...\.....II-4

1.5 Installation Requirements\...\...\...\...\...\...\...\...\.....II-5

**TABLE OF CONTENTS**

1.6 Operational
Tests\...\...\...\...\...\...\...\...\...\...\...\....II-6

1.7 Acceptance Tests and Data Required\...\...\...\...\...\.....II-6

1.8 Joint Inspection Requirements\...\...\...\...\...\...\...\....II-7

Part III - Specification for Line Concentrator Detailed Equipment
Requirements

1\.
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....III-1

2\. Number of Subscriber Lines\...\...\...\...\...\...\...\...\...III-2

3\. Loop
Resistance\...\...\...\...\...\...\...\...\...\...\...\.....III-2

4\. Traffic
Data\...\...\...\...\...\...\...\...\...\...\...\...\.....III-3

5\. Type of
Ringing\...\...\...\...\...\...\...\...\...\...\...\.....III-3

6\. Central Office Equipment Interface\...\...\...\...\...\....III-3

7\. Transmission Facilities\...\...\...\...\...\...\...\...\...\...III-4

8\. Power Equipment Requirements\...\...\...\...\...\...\...\....III-5

9\. Remote
Terminal\...\...\...\...\...\...\...\...\...\...\...\.....III-6

10\.
Alternates\...\...\...\...\...\...\...\...\...\...\...\...\...\....III-7

11\. Explanatory
Notes\...\...\...\...\...\...\...\...\...\...\...\...III-7

Part IV - Specification For Line Concentrators Detailed Requirements;
Bidder Supplied Information

1\.
General\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....IV-1

2\. Performance Objectives\...\...\...\...\...\...\...\...\...\....IV-1

3\. Equipment QuantitiesDependent on System Design\...\....IV-2

4\. Power Requirements\...\...\...\...\...\...\...\...\...\...\.....IV-2

5\. Temperature and Humidity Limitations\...\...\...\...\.....IV-2

6\. Explanatory
Notes\...\...\...\...\...\...\...\...\...\...\...\...IV-3

INDEX:

Specification, Line Concentrator

**ABBREVIATIONS**

A Ampere

AC or ac Alternating Current

ANSI American National Standards Institute

ASTM American Society for Testing Materials

CCS Centum (hundred) Call Seconds

CFR Code of Federal Regulations

CO Central Office

COE Central Office Equipment

CSA Carrier Serving Area

dB Decibel

dBm0 Decibel Metallic Referenced to Zero

DC or dc Direct Current

DP Dial Pulse

DS1 Digital Signal Level 1 (1.544 Mb/s)

ERL Echo Return Loss

Hz Hertz

IEEE Institute of Electrical and Electronic Engineers

LC Line Concentrator

MDF Main Distributing Frame

MF Multifrequency

PC Printed Circuit

REA Rural Electrification Administration

rms Root Mean Square

RUS Rural Utilities Service

SRL Singing Return Loss

V Volts

VF Voice Frequency

øC Degree Centigrade

øF Degree Fahrenheit

**BULLETIN TO CFR PARAGRAPH NUMBER CROSS-REFERENCE**

**PART I GENERAL SPECIFICATION**

[1753E-004]{.underline} [1755.397]{.underline}\
\
1. (a)\
1.1 (a)(1)\
1.1.1 (a)(1)(i)\
1.1.2 (a)(1)(ii)\
1.1.3 (a)(1)(iii)\
1.2 (a)(2)\
1.3 (a)(3)\
1.3.1 (a)(3)(i)\
1.4 (a)(4)\
1.5 (a)(5)\
1.5.1 (a)(5)(i)\
1.5.2 (a)(5)(ii)\
1.5.3 (a)(5)(iii)\
1.6 (a)(6)\
1.7 (a)(7)\
1.7.1 (a)(7)(i)\
1.8 (a)(8)\
1.8.1 (a)(8(i)\
\
2. (b)\
2.1 (b)(1)\
2.2 (b)(2)\
2.3 (b)(3)\
2.4 (b)(4)\
2.5 (b)(5)\
2.6 (b)(6)\
2.7 (b)(7)\
\
3. (c)\
3.1 (c)(1)\
3.2 (c)(2)\
\
4. (d)\
4.1 (d)(1)\
\
5. (e)\
5.1 (e)(1)\
\
6. (f)\
6.1 (f)(1)\
6.1.1 (f)(1)(i)\
6.1.2 (f)(1)(ii)\
6.2 (f)(2)\
6.2.1 (f)(2)(i)\
6.2.2 (f)(2)(ii)\
6.2.3 (f)(2)(iii)

[1753E-004]{.underline} [1755.397]{.underline}\
\
6.3 (f)(3)\
6.3.1 (f)(3)(i)\
6.3.2 (f)(3)(ii)\
6.3.3 (f)(3)(iii)\
7. (g)\
7.1 (g)(1)\
7.1.1 (g)(1)(i)\
7.1.2 (g)(1)(ii)\
7.2 (g)(2)\
7.3 (g)(3)\
\
8. (h)\
8.1 (h)(1)\
8.2 (h)(2)\
8.3 (h)(3)\
8.4 (h)(4)\
8.5 (h)(5)\
8.6 (h)(6)\
8.7 (h)(7)\
8.8 (h)(8)\
8.9 (h)(9)\
8.10 (h)(10)\
8.11 (h)(11)\
8.12 (h)(12)\
8.13 (h)(13)\
8.13.1 (h)(13)(i)\
8.13.2 (h)(13)(ii)\
8.14 (h)(14)\
8.15 (h)(15)\
8.16 (h)(16)\
8.17 (h)(17)\
8.18 (h)(18)\
8.19 (h)(19)\
8.20 (h)(20)\
8.20.1 (h)(20)(i)\
8.20.2 (h)(20)(ii)\
8.20.3 (h)(20)(iii)\
8.20.4 (h)(20)(iv)\
8.20.4.1 (h)(20)(iv)(A)\
8.20.4.2 (h)(20)(iv)(B)\
8.20.4.3 (h)(20)(iv)(C)\
\
9. (i)\
9.1 (i)(1)

[1753E-004]{.underline} [1755.397]{.underline}\
\
10. (j)\
10.1 (j)(1)\
10.1.1 (j)(1)(i)\
10.1.2 (j)(1)(ii)\
10.1.3 (j)(1)(iii)\
10.1.3.1 (j)(1)(iii)(A)\
10.1.3.2 (j)(1)(iii)(B)\
10.1.3.3 (j)(1)(iii)(C)\
10.1.3.4 (j)(1)(iii)(D)\
10.1.3.5 (j)(1)(iii)(E)\
10.1.4 (j)(1)(iv)\
10.1.4.1 (j)(1)(iv)(A)\
10.1.4.2 (j)(1)(iv)(B)\
10.1.4.3 (j)(1)(iv)(C)\
10.1.4.4 (j)(1)(iv)(D)\
10.1.4.5 (j)(1)(iv)(E)\
10.1.5 (j)(1)(v)\
10.1.6 (j)(1)(vi)\
10.1.6.1 (j)(1)(vi)(A)\
10.1.6.2 (j)(1)(vi)(B)\
10.1.6.3 (j)(1)(vi)(C)\
10.1.6.4 (j)(1)(vi)(D)\
10.2 (j)(2)\
10.2.1 (j)(2)(i)\
10.2.2 (j)(2)(ii)\
10.3 (j)(3)\
10.4 (j)(4)\
10.4.1 (j)(4)(i)\
10.4.2 (j)(4)(ii)\
10.4.3 (j)(4)(iii)\
\
11. (k)\
11.1 (k)(1)\
11.2 (k)(2)\
11.2.1 (k)(2)(i)\
11.2.2 (k)(2)(ii)\
11.2.3 (k)(2)(iii)\
11.2.4 (k)(2)(iv)\
11.3 (k)(3)\
11.4 (k)(4)\
11.5 (k)(5)\
11.5.1 (k)(5)(i)\
11.5.2 (k)(5)(ii)\
11.5.2.1 (k)(5)(ii)(A)\
11.5.2.2 (k)(5)(ii)(B)\
11.6 (k)(6)\
11.7 (k)(7)\
11.8 (k)(8)\
11.9 (k)(9)\
11.9.1 (k)(9)(i)

[1753E-004]{.underline} [1755.397]{.underline}

11.10 (k)(10)\
11.10.1 (k)(10)(i)\
11.10.2 (k)(10)(ii)\
11.10.3 (k)(10)(iii)\
11.10.4 (k)(10)(iv)\
11.10.5 (k)(10)(v)\
11.10.6 (k)(10)(vi)\
11.10.7 (k)(10)(vii)\
11.10.8 (k)(10)(viii)\
\
12. (l)\
12.1 (l)(1)\
12.2 (l)(2)\
12.2.1 (l)(2)(i)\
12.2.2 (l)(2)(ii)\
12.2.3 (l)(2)(iii)\
12.3 (l)(3)\
12.3.1 (l)(3)(i)\
12.3.2 (l)(3)(ii)\
12.3.3 (l)(3)(iii)\
12.3.4 (l)(3)(iv)\
12.4 (l)(4)\
12.4.1 (l)(4)(i)\
12.4.2 (l)(4)(ii)\
12.4.3 (l)(4)(iii)\
12.4.4 (l)(4)(iv)\
12.4.5 (l)(4)(v)\
12.4.6 (l)(4)(vi)\
12.4.7 (l)(4)(vii)\
12.5 (l)(5)\
12.5.1 (l)(5)(i)\
12.5.2 (l)(5)(ii)\
12.5.3 (l)(5)(iii)\
12.6 (l)(6)\
12.7 (l)(7)\
12.8 (l)(8)\
\
13. (m)\
13.1 (m)(1)\
13.1.1 (m)(1)(i)\
13.1.2 (m)(1)(ii)\
13.2 (m)(2)\
\
14. (n)\
14.1 (n)(1)\
14.1.1 (n)(1)(i)\
14.1.2 (n)(1)(i)\
14.2 (n)(2)

14.2.1 (n)(2)(i)

14.2.2 (n)(2)(ii)

[1753E-004]{.underline} [1755.397]{.underline}\
\
15. (o)\
15.1 (o)(1)\
\
16. (p)\
16.1 (p)(1)\
16.2 (p)(2)\
16.2.1 (p)(2)(i)\
16.2.2 (p)(2)(ii)\
16.2.3 (p)(2)(iii)\
16.2.4 (p)(2)(iv)

[1753E-004]{.underline} [1755.397]{.underline}\
\
16.3 (p)(3)\
16.3.1 (p)(3)(i)\
16.3.2 (p)(3)(ii)\
16.3.3 (p)(3)(iii)\
16.3.4 (p)(3)(iv)\
16.3.5 (p)(3)(v)\
16.3.6 (p)(3)(vi)\
16.3.7 (p)(3)(vii)\
16.3.8 (p)(3)(viii)\
16.4 (p)(4)

**BULLETIN TO CFR PARAGRAPH NUMBER CROSS-REFERENCE**

**PART II INSTALLATION**

[1753E-004]{.underline} [1755.397]{.underline}\
\
1. (q)\
1.1 (q)(1)\
1.2 (q)(2)\
1.2.1 (q)(2)(i)\
1.2.2 (q)(2)(ii)\
1.2.3 (q)(2)(iii)\
1.2.4 (q)(2)(iv)\
1.2.5 (q)(2)(v)\
1.2.6 (q)(2)(vi)\
1.2.7 (q)(2)(vii)\
1.2.8 (q)(2)(viii)\
1.2.9 (q)(2)(ix)\
1.2.10 (q)(2)(x)\
1.2.11 (q)(2)(xi)\
1.2.12 (q)(2)(xii)\
1.2.13 (q)(2)(xiii)\
1.2.14 (q)(2)(xiv)\
1.2.15 (q)(2)(xv)\
1.2.16 (q)(2)(xvi)\
1.2.17 (q)(2)(xvii)\
1.2.18 (q)(2)(xviii)\
1.2.19 (q)(2)(xix)\
1.2.20 (q)(2)(xx)\
1.3 (q)(3)\
1.3.1 (q)(3)(i)\
1.3.2 (q)(3)(ii)\
1.3.3 (q)(3)(iii)\
1.3.4 (q)(3)(iv)\
1.3.5 (q)(3)(v)\
1.3.6 (q)(3)(vi)\
1.3.7 (q)(3)(vii)\
1.3.8 (q)(3)(viii)

[1753E-004]{.underline} [1755.397]{.underline}\
\
1.3.9 (q)(3)(ix)\
1.3.10 (q)(3)(x)\
1.3.11 (q)(3)(xi)\
1.3.12 (q)(3)(xii)\
1.3.13 (q)(3)(xiii)\
1.3.14 (q)(3)(xiv)\
1.3.15 (q)(3)(xv)\
1.3.16 (q)(3)(xvi)\
1.3.17 (q)(3)(xvii)\
1.3.18 (q)(3)(xviii)\
1.3.19 (q)(3)(xix)\
1.3.20 (q)(3)(xx)\
1.3.21 (q)(3)(xxi)\
1.4 (q)(4)\
1.4.1 (q)(4)(i)\
1.4.2 (q)(4)(ii)\
1.4.3 (q)(4)(iii)\
1.4.4 (q)(4)(iv)\
1.4.5 (q)(4)(v)\
1.4.6 (q)(4)(vi)\
1.4.7 (q)(4)(vii)\
1.4.8 (q)(4)(viii)\
1.5 (q)(5)\
1.5.1 (q)(5)(i)\
1.5.2 (q)(5)(ii)\
1.5.3 (q)(5)(iii)\
1.5.3.1 (q)(5)(iii)(A)\
1.5.3.2 (q)(5)(iii)(B)\
1.5.3.3 (q)(5)(iii)(C)\
1.5.3.4 (q)(5)(iii)(D)\
1.6 (q)(6)\
1.6.1 (q)(6)(i)

[1753E-004]{.underline} [1755.397]{.underline}\
\
1.6.2 (q)(6)(ii)\
1.6.3 (q)(6)(iii)\
1.6.4 (q)(6)(iv)\
1.6.5 (q)(6)(v)\
1.7 (q)(7)\
1.7.1 (q)(7)(i)\
1.7.1.1 (q)(7)(i)(A)\
1.7.1.2 (q)(7)(i)(B)\
1.7.1.3 (q)(7)(i)(C)

[1753E-004]{.underline} [1755.397]{.underline}\
\
\
1.7.1.4 (q)(7)(i)(D)\
1.7.2 (q)(7)(ii)\
1.7.3 (q)(7)(iii)\
1.8 (q)(8)\
1.8.1 (q)(8)(i)\
1.8.1.1 (q)(8)(i)(A)\
1.8.1.2 (q)(8)(i)(B)\
1.8.1.3 (q)(8)(i)(C)\
1.8.2 (q)(8)(ii)

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

**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) 642-4900.

**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.

**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 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.

**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. SUBSCRIBER LINES**

**6.1** **[General]{.underline}**

**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]{.underline}**

**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:]{.underline}** 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:]{.underline}** 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)]{.underline} [High Group Frequencies
(Hz)]{.underline}

[1209]{.underline} [1336]{.underline} [1477]{.underline}
[1633]{.underline}

697 1 2 3 Spare

770 4 5 6 Spare

852 7 8 9 Spare

941 \* 0 \# Spare

**6.3 [Ringing]{.underline}**

**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. TRAFFIC**

**7.1 [General]{.underline}**

**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 means for displaying
the information locally (or at a remote location when available).

**8. TRANSMISSION REQUIREMENTS**

**8.1** **[General]{.underline}:** 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]{.underline}:** 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]{.underline}:** 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]{.underline}:** 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]{.underline}:** 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]{.underline}:** 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]{.underline}:** 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.

**8.8 [60 Hz Longitudinal Current Immunity]{.underline}:** 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**

![](media/image1.wmf)

Notes:

1\. Wilcom T194C or Equivalent (900 ohm termination, C-message

weighting, hold coil off)

2\. SNC Noise Choke 35 W, or equivalent

3\. Test at 0.020 Adc and 0.070 Adc

4\. 2 ± 0.001 microfarad, 150 Vdc

**8.9 [Steady Noise (Idle Channel at 900 Ohm Impedance)]{.underline}:**
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]{.underline}:** 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]{.underline}:** 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]{.underline}:** The digital line concentrator
shall not introduce more than one error in 108 bits averaged over a
5-minute period, excluding the least significant bit.

**8.13** **[Quantizing Distortion]{.underline}**

**8.13.1** The system shall meet the following requirements:

Input Level (dBm0) Minimum Signal to Distortion

[1004 or 1020 Hz]{.underline} [With C-Message Weighting]{.underline}

0 to -30 33 dB

-30 to -40 27 dB

-40 to -45 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]{.underline}:** The overload level shall be +3
dBm0.

**8.15 [Gain Tracking (Linearity)]{.underline}** shall meet the
following requirements:

[Input Signal Level]{.underline}^1^ [Maximum Gain Deviation]{.underline}

+3 to -37 dBm0 ± 0.5 dB

-37 to -50 dBm0 ± 1 dB

^1^ 1004 Hz reference at 0 dBm0.

**8.16 [Frequency Response (Loss Relative to 1004 Hz)]{.underline}** for
line-to-line (via trunk group or intra-link) connections shall meet the
following requirements:

[Frequency (Hz)]{.underline} [Loss at 0 dBm0 Input]{.underline}^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

**8.17 [Envelope Delay Distortion]{.underline}:** On any properly
established connection, the envelope delay distortion shall not exceed
the following limits:

[Frequency (Hz)]{.underline} [Microseconds]{.underline}

1000 to 2600 190

800 to 2800 350

600 to 3000 500

400 to 3200 700

**8.18 [Absolute Delay]{.underline}:** 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]{.underline}:** 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]{.underline}**

**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 mu-255 encoding
law and D3 encoding format, and arranged to interface with a T1 span
line.

**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. ELECTRICAL PROTECTION**

**10.1 [Surge Protection]{.underline}**

**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-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.

**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.

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**Figure 3**

**Explanation of Surge Waveshape**

![](media/image2.wmf){width="5.895833333333333in"
height="4.4006944444444445in"}

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).

**Figure 4**

**Current Surge Test**

![](media/image3.wmf){width="5.710416666666666in" height="3.725in"}

V~L~ = Not to exceed 1000V

V~B~ = Charging Voltage

Z~100~ = Test Specimen Impedance to be measured at 100 Hz.

R~P~ = Parallel Resistance (Waveshape)

R~S~ = Series Resistance (Current Limiting)

Z~100~ R~S~ R~P~ V~B~

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

0 5 ∞ 2500

1 4 ∞ 2500

2 3 ∞ 2500

3 2 ∞ 1670

4 1 ∞ 1250

5 0 ∞ 1000

7.5 0 15 1000

10 0 10 1000

15 0 7.5 1000

20 0 6.7 1000

25 0 6.25 1000

30 0 6 1000

40 0 5.7 1000

50 0 5.5 1000

**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.

**Figure 5**

**Explanation of Arrester Response Delay Time**

![](media/image4.wmf){width="5.895833333333333in"
height="4.4006944444444445in"}

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

**Figure 6**

**60 Hz Current Surge Test**

![](media/image5.wmf){width="5.895833333333333in"
height="4.4006944444444445in"}

V - 700 Volts root mean square (rms) (Approximately 1000V

Peak).

Z60 - Test specimen impedance to be measured at 60 Hz.

R~S~ - Series Resistance (current limiting) in each

side of line. (Source impedance never less

than 50Ω longitudinal.)

  ----------------------------------- -----------------------------------
  Z60 Hz                              R~S~

  \_\_\_\_\_\_\_                      \_\_\_\_\_

  0                                   140

  10                                  120

  20                                  100

  50                                  100

  Over 50                             100
  ----------------------------------- -----------------------------------

**10.2 [Dielectric Strength]{.underline}**

**10.2.1** Arresters shall be removed for all dielectric strength tests.

**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]{.underline}:** 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]{.underline}**

**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]{.underline}:** 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 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]{.underline}:** 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]{.underline}:** 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]{.underline}:** 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]{.underline}:**

**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 equipment (cabinet) exposed to direct
sunlight may be substituted.

**11.6 [Stenciling]{.underline}:** 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]{.underline}:** 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 and Television Interference]{.underline}:** 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.

**11.9 [Housing]{.underline}**

**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]{.underline}**

**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 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** Protector makes and types used shall be RUS accepted.

**12. POWER EQUIPMENT**

**12.1 [General]{.underline}:** When specified, batteries and charging
equipment shall be supplied for the remote terminal of the line
concentrator.

**12.2 [Operating Voltage]{.underline}**

**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]{.underline}**

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

**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]{.underline}**

**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.

**Figure 7**

**Charger Noise Test**

![](media/image6.wmf){width="5.895833333333333in"
height="4.4006944444444445in"}

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.

**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]{.underline}**

**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]{.underline}:** 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]{.underline} 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:]{.underline}** 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. FUSING REQUIREMENTS**

**13.1 [General]{.underline}**

**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]{.underline}:** 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. TROUBLE LOCATION AND TEST**

**14.1 [Equipment]{.underline}**

**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]{.underline}**

**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.

**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** The following information shall also be furnished:

**16.3.1** 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 II**

**INSTALLATION AND ACCEPTANCE**

**1. INSTALLATION AND ACCEPTANCE**

**1.1 [General]{.underline}:** 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]{.underline}:** 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);

**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.

**1.3 [Responsibilities of Bidder]{.underline}:** 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 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]{.underline}:** 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.

**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]{.underline}**

**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

**1.5.3.4** Other adverse conditions resulting from failure to meet
generally accepted standards of good workmanship.

**1.6 [Operational Tests]{.underline}**

**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]{.underline}**

**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

**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]{.underline}**

**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 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]{.underline} [No. of Lines]{.underline} [Central
Office]{.underline}

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**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.

**2. NUMBER OF SUBSCRIBER LINES**

[Equipped]{.underline} [Wired Only]{.underline}

Single-Party \_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_

Pay Station (Type:\_\_\_\_\_\_\_\_) \_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_

Other (Describe:\_\_\_\_\_\_\_\_\_\_) \_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_

Total \_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_

**3. LOOP RESISTANCE**

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

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

[No. of Lines]{.underline}

1200 - 1900 ohms \_\_\_\_\_\_\_\_\_\_\_\_

1901 - 3200 ohms \_\_\_\_\_\_\_\_\_\_\_\_

3201 - 4500 ohms \_\_\_\_\_\_\_\_\_\_\_\_

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

No. of Lines

1200 ohms (Prepay) \_\_\_\_\_\_\_\_\_\_\_\_

1000 ohms (Semi-Postpay) \_\_\_\_\_\_\_\_\_\_\_\_

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

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

\_\_\_\_ By Bidder

\_\_\_\_ By Owner (Quantity and Type) \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**4. TRAFFIC DATA**

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

\_\_\_\_\_\_\_\_CCS/Line. (Assume originating & terminating equal.)

**4.2** Percent Intra-Calling \_\_\_\_\_\_\_\_\_\_\_\_\_

**4.3** Total Busy Hour Calls \_\_\_\_\_\_\_\_\_\_\_\_\_

**5. TYPE 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** COE will be:

**6.1.1** COE Manufacturer
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Type\_\_\_\_\_\_\_\_\_\_\_ Year\_\_\_\_\_\_\_\_\_\_\_
Generic\_\_\_\_\_\_\_\_\_\_\_

**6.1.2** \_\_\_ See digital central office specification for the
switchboard at
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

**6.2** Interface will be:

**6.2.1** \_\_\_ Line Circuit(s)

**6.2.2** \_\_\_ Direct Digital Interface

**6.2.3** \_\_\_ Other (Describe)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**6.3** Mounting rack for line concentrator furnished by:

\_\_\_ Bidder \_\_\_ Owner

(Specify width and height of rack available) \_\_\_\_\_ \_\_\_\_\_\_

Width Height

**6.4** Equipment to be installed in existing building:

\_\_\_ Yes (Attach detailed plan) \_\_\_ No

**7. TRANSMISSION FACILITIES**

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

**7.1.1** Type:

\_\_\_ VF Carrier Derived Circuits

\_\_\_ Digital Span Line (DS1)

\_\_\_ Other
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

(Attach a layout of the transmission facilities between the central
office and the remote terminals describing transmission and signaling
parameters, routing and resistance where applicable).

**7.1.2** Utilizes physical plant

\_\_\_ Cable Pairs (Existing/New)

\_\_\_ Other
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Note: Unless otherwise stated, physical plant will be

supplied by the owner.

**7.1.3** Terminal equipment for transmission facility to be supplied
by:

\_\_\_ Owner \_\_\_ Bidder

**7.1.3.1** Carrier e/w voice terminations \_\_\_ Yes \_\_\_ No

Manufacturer and type \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Central office voice terminations

Equipped\_\_\_\_\_\_\_\_, Wired Only\_\_\_\_\_\_\_\_

**7.1.3.2** Digital span line (DS1) supplied by

\_\_\_ Owner \_\_\_ Bidder

Manufacturer and Type \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**7.1.3.3** Number of repeaters (per span line) \_\_\_\_\_\_\_\_\_\_\_\_

**7.1.3.4** Diverse (alternate) span line routing required

\_\_\_ Yes (Describe in Item 11) \_\_\_ No

**7.1.3.5** Span line terminations only \_\_\_ Yes \_\_\_ No

**7.1.3.6** Span line power required \_\_\_ Yes \_\_\_ No

(CO and Remote Terminals)

**7.1.3.7** Physical facility between CO and remote

Loop Resistance \_\_\_\_\_\_\_\_ohms, Length \_\_\_\_\_\_\_meters

**8. POWER EQUIPMENT REQUIREMENTS**

**8.1** Central Office Terminal

**8.1.1** Owner-furnished -48 volt dc power \_\_\_ Yes \_\_\_ No

**8.1.2** Other (Describe)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**8.1.3** Standby power is available \_\_\_ Yes \_\_\_ No

**8.2** Remote Terminal

**8.2.1** Owner-furnished -48 vdc power \_\_\_ Yes \_\_\_ No

**8.2.2** Bidder-furnished power supply \_\_\_ Yes \_\_\_ No

**8.2.3** AC power available at site:

\_\_\_ 110 vac, 60 Hz, single-phase

\_\_\_ Other (Describe in Item 11)

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

**8.2.5** Batteries supplied shall be:

\_\_\_ Lead Calcium

\_\_\_ Stabilized Electrolyte \_\_\_ Sealed Lead Acid

\_\_\_ Other (Describe in item 11)

**8.2.6** Standby power is available \_\_\_ Yes \_\_\_ No

**9. REMOTE TERMINAL**

**9.1** Mounting

**9.1.1** \_\_\_ Outside Housing (To be furnished by bidder)

**9.1.2** \_\_\_ Concrete Slab to be furnished by owner

(Bidder to supply construction details after award.)

**9.1.3** \_\_\_ Manhole, environmentally controlled (Describe in Item
11)

**9.1.4** \_\_\_ Pedestal Mounting

**9.1.5** \_\_\_ Pole Mounting (Owner-furnished installed pole)

**9.1.6** \_\_\_ Prefab Building (Owner-furnished site)

**9.2** Equipment is to be installed in an existing building.

\_\_\_ Yes \_\_\_ No

(Attach detailed plan.)

**9.3** Other (Describe)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**10. ALTERNATES**

**11. EXPLANATORY NOTES**

**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. PERFORMANCE OBJECTIVES**

**2.1** Reliability (See Part I, paragraph 3)

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**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]{.underline} [Quantity Equipped]{.underline} [Quantity Wired
Only]{.underline}

\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**4. POWER REQUIREMENTS**

**4.1** Central Office Terminal

Voltage \_\_\_\_\_\_\_\_\_\_\_\_

Current Drain (Amps) Normal \_\_\_\_\_\_\_\_\_\_, Peak
\_\_\_\_\_\_\_\_\_

Fuse Qty \_\_\_\_\_\_\_\_\_, Size \_\_\_\_\_\_\_\_\_\_, Type
\_\_\_\_\_\_\_\_\_

Heat Dissipation (BTU/Hr.)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**4.2** Remote Terminal

AC or DC \_\_\_\_\_\_\_\_\_\_\_\_\_\_

Voltage \_\_\_\_\_\_\_\_\_\_\_\_\_\_

Current Drain (Amps) Normal \_\_\_\_\_\_\_\_\_\_\_, Peak
\_\_\_\_\_\_\_\_\_

Fuse Qty \_\_\_\_\_\_\_\_\_, Size \_\_\_\_\_\_\_\_\_\_\_, Type
\_\_\_\_\_\_\_\_\_

Heat Dissipation (BTU/Hr.)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

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

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**5. TEMPERATURE AND HUMIDITY LIMITATIONS**

**5.1** Temperature

[Central Office]{.underline} [Remote]{.underline}\*

Maximum ºF (ºC) \_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_

Minimum ºF (ºC) \_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_

\*Show conditions outside bidder-furnished housing.

**5.2** Relative Humidity

[Central Office]{.underline} [Remote]{.underline}\*

Maximum \_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_

Minimum \_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_

\*Show conditions outside bidder-furnished housing.

**6. EXPLANATORY NOTES**