RUS Standard for Acceptance Tests and Measurements of Telecommunications Plant

DEPARTMENT OF AGRICULTURE

Rural Utilities Service

7 CFR Part 1755

RUS Standard for Acceptance Tests and Measurements of

Telecommunications Plant

AGENCY: Rural Utilities Service, USDA.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The Rural Utilities Service (RUS) amends its regulations on

Telecommunications Standards and Specifications for Materials,

Equipment and Construction, by rescinding RUS Bulletin 345-63, RUS

Standard for Acceptance Tests and Measurements of Telephone Plant, PC-

4, and codifying the revised RUS standard at 7 CFR 1755.400 through 7

CFR 1755.407, in the Code of Federal Regulations. The revised standard:

Updates the acceptance tests and measurements for copper conductor

telecommunications plant; includes a section on acceptance tests and

measurements for fiber optic cable plant; includes a section on

acceptance tests and measurements for voiceband data transmission; and

includes a shield or armor ground resistance test to determine outer

jacket cable damage.

DATES: Effective date: June 2, 1997.

Incorporation by reference: Incorporation by reference of certain

publications listed in this final rule is approved by the Director of

the Federal Register as of June 2, 1997.

FOR FURTHER INFORMATION CONTACT: Charlie I. Harper, Jr., Chief, Outside

Plant Branch, Telecommunications Standards Division, Rural Utilities

Service, room 2837, STOP 1598, South Building, U.S. Department of

Agriculture, Washington, DC 20250-1598, telephone number (202) 720-

0667.

SUPPLEMENTARY INFORMATION:

Executive Order 12866

This final rule has been determined to be not significant and

therefore has not been reviewed by the Office of Management and Budget.

Executive Order 12988

This final rule has been reviewed under Executive Order 12988,

Civil Justice Reform. RUS has determined that this final rule meets the

applicable standards provided in section 3 of that Executive Order.

Regulatory Flexibility Act Certification

The Administrator of RUS has determined that this final rule will

not have a significant economic impact on a substantial number of small

entities, as defined by the Regulatory Flexibility Act (5 U.S.C. 601 et

seq.). This final rule involves standards and specifications, which may

increase the direct short-term costs to RUS borrowers. However, the

long-term direct economic costs are reduced through greater durability

and lower maintenance cost over time.

Information Collection and Recordkeeping Requirements

The reporting and recordkeeping requirements contained in the final

rule were approved by the Office of Management and Budget (OMB)

pursuant to the Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35,

as amended) under control number 0572-0059.

Send questions or comments regarding this burden or any aspect of

these collections of information, including suggestions for reducing

the burden, to F. Lamont Heppe, Jr., Director, Program Support and

Regulatory Analysis, Rural Utilities Service, U.S. Department of

Agriculture,

[[Page 23959]]

Stop 1522, Washington, DC 20250-1522, Fax: (202) 720-4120.

National Environmental Policy Act Certification

The Administrator of RUS has determined that this final rule will

not significantly affect the quality of the human environment as

defined by the National Environmental Policy Act of 1969 (42 U.S.C.

4321 et seq.) Therefore, this action does not require an environmental

impact statement or assessment.

Catalog of Federal Domestic Assistance

The program described by this final rule is listed in the Catalog

of Federal Domestic Assistance programs under No. 10.851, Rural

Telephone Loans and Loan Guarantees; and No. 10.852, Rural Telephone

Bank Loans. This catalog is available on a subscription basis from the

Superintendent of Documents, the United States Government Printing

Office, Washington, DC 20402.

Executive Order 12372

This final rule is excluded from the scope of Executive Order

12372, Intergovernmental Consultation, which may require consultation

with State and local officials. A Notice of Final rule titled

Department Programs and Activities Excluded from Executive Order 12372

(50 FR 47034) exempts RUS and RTB loans and loan guarantees, and RTB

bank loans, to governmental and nongovernmental entities from coverage

under this Order.

Background

RUS issues publications titled ``Bulletin'' which serve to guide

borrowers regarding already codified policy, procedures, and

requirements needed to manage loans, loan guarantee programs, and the

security instruments which provide for and secure RUS financing. RUS

issues standards and specifications for the construction of telephone

facilities financed with RUS Loan Funds. RUS is rescinding Bulletin

345-63, ``RUS Standard for Acceptance Tests and Measurements of

Telephone Plant, PC-4,'' and to codifying this standard in 7 CFR

1755.400 through 7 CFR 1755.407, RUS Standard for Acceptance Tests and

Measurements of Telecommunications Plant.

This standard is used to determine the acceptability of installed

telecommunications plant. The current standard with regard to copper

cable plant acceptance tests and measurements has become outdated as a

result of technological advancements made in copper cable plant

acceptance test methods during the past fourteen years. Therefore to

assure RUS borrowers that their installed copper cable plant is of the

highest quality, the revised standard will update acceptance test and

measurement methods for copper cable plant.

There is currently a need to include into the standard a section

dealing with standardized test methods and measurements for installed

fiber optic cable plant. Presently acceptance test methods and

measurements for fiber optic cable plant are developed by each

consulting engineer resulting in a variety of test methods and

measurements which in turn results in higher construction costs to RUS

borrowers. By providing standardized acceptance test methods and

measurements for fiber optic cable plant, RUS will be assisting its

borrowers by decreasing their construction costs for fiber optic cable

installation.

There is currently a need to include into the standard a section

dealing with standardized test methods and measurements for voiceband

data transmission. Because RUS borrowers are increasing their usage of

modems to transmit data over telecommunications transmission

facilities, standardized test methods and measurements are needed to

ensure that the transmission facilities are acceptable for data

transmission.

There is presently a need to include into the current standard a

standardized shield or armor ground resistance test method and a

minimum requirement to determine when the outer cable jacket is damaged

as a result of the installation procedures. This standard test method

and minimum requirement will result in cost savings to RUS borrowers

because the variety of test methods and minimum requirements presently

being used by consulting engineers and contractors will be eliminated.

This action establishes RUS standardized acceptance test methods

and measurements to determine acceptability of installed

telecommunications plant. These standardized acceptance test methods

and measurements will afford RUS telephone borrowers an economical and

efficient means of reducing their construction costs.

On August 28, 1996, RUS published a proposed rule (61 FR 44195) to

rescind RUS Bulletin 345-63, RUS Standard for Acceptance Tests and

Measurements of Telephone Plant, PC-4, and to codify the revised RUS

Standard for Acceptance Tests and Measurements of Telecommunications

Plant in 7 CFR 1755.400 through 7 CFR 1755.407. Comments on this

proposed rule were due October 28, 1996. No comments were received by

this due date.

List of Subjects in 7 CFR Part 1755

Incorporation by reference, Loan programs--communications,

Reporting and recordkeeping requirements, Rural areas, Telephone.

For the reasons set out in the preamble, RUS amends chapter XVII of

title 7 of the Code of Federal Regulations as follows:

Part 1755--Telecommunications Standards and Specifications for

Materials, Equipment and Construction

1. The authority citation for part 1755 continues to read as

follows:

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

Sec. 1755.97 [Amended]

2. Section 1755.97 is amended by removing the entry RUS Bulletin

345-63 from the table.

3. Section 1755.98 is amended by adding the entry 1755.400 through

1755.407 to the table in numerical order to read as follows:

Sec. 1755.98 List of telephone standards and specifications included

in other 7 CFR parts.

* * * * *

------------------------------------------------------------------------

Section Issue date Title

------------------------------------------------------------------------

* * * *

* * *

1755.400 through 1755.407... [Effective date of RUS Standard for

final rule]. Acceptance Tests

and Measurements of

Telecommunications

Plant.

* * * *

* * *

------------------------------------------------------------------------

[[Page 23960]]

4. Sections 1755.400 through 1755.407 are added to read as follows:

Sec. 1755.400 RUS standard for acceptance tests and measurements of

telecommunications plant.

Sections 1755.400 through 1755.407 cover the requirements for

acceptance tests and measurements on installed copper and fiber optic

telecommunications plant and equipment.

Sec. 1755.401 Scope.

(a) Acceptance tests outlined in Secs. 1755.400 through 1755.407

are applicable to plant constructed by contract or force account. This

testing standard provides for the following:

(1) Specific types of tests or measurements for the different types

of telecommunications plant and equipment;

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

(3) The expected results and tolerances permitted to meet the

acceptable standards and objectives;

(4) Suggested formats for recording the results of the measurements

and tests; and

(5) Some probable causes of nonconformance and methods for

corrective action, where possible.

(b) Alternative methods of measurements that provide suitable

alternative results shall be permitted with the concurrence of the

Rural Utilities Service (RUS).

(c) For the purpose of this testing standard, a ``measurement''

shall be defined as an evaluation where quantitative data is obtained

(e.g., resistance in ohms, structural return loss in decibels (dB),

etc.) and a ``test'' shall be defined as an evaluation where no

quantitative data is obtained (e.g., a check mark indicating

conformance is usually the result of the test).

(d) The sequence of tests and measurements described in this

standard have been prepared as a guide. Variations from the sequence

may be necessary on an individual application basis.

(e) There is some overlap in the methods of testing shown; also,

the extent of each phase of testing may vary on an individual basis.

The borrower shall determine the overall plan of testing, the need and

extent of testing, and the responsibility for each phase of testing.

Sec. 1755.402 Ground resistance measurements.

(a) The resistance of the central office (CO) and the remote

switching terminal (RST) ground shall be measured before and after it

has been bonded to the master ground bar (MGB) where it is connected to

the building electric service ground.

(b) The ground resistance of electronic equipment such as span line

repeaters, carrier terminal equipment, concentrators, etc. shall be

measured.

(c) Method of measurement. The connection of test equipment for the

ground resistance measurement shall be as shown in Figure 1. Refer to

RUS Bulletin 1751F-802, ``Electrical Protection Grounding

Fundamentals,'' for a comprehensive discussion of ground resistance

measurements.

(d) Test equipment. The test equipment for making this measurement

is shown in Figure 1 as follows:

BILLING CODE 3410-15-P

[[Page 23961]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.023

BILLING CODE 3410-15-C

[[Page 23962]]

(e) Applicable results. (1) For the CO and RST, the resistance

after the bond has been made to the MGB electric service ground shall

not exceed 5 ohms. Where the measured ground resistance exceeds 5 ohms,

the borrower shall determine what additional grounding, if any, shall

be provided.

(2) For electronic equipment, the ground resistance shall not

exceed 25 ohms. Where the measured ground resistance exceeds 25 ohms,

the borrower shall determine what additional grounding, if any, shall

be provided.

(3) When ground resistance measurements exceed the ground

resistance requirements of paragraphs (e)(1) and (e)(2) of this

section, refer to RUS Bulletin 1751F-802, ``Electrical Protection

Grounding Fundamentals,'' for suggested methods of reducing the ground

resistance.

(f) Data record. Results of the CO and RST ground resistance

measurements shall be recorded. A suggested format similar to Format I,

Outside Plant Acceptance Tests--Subscriber Loops, in Sec. 1755.407 or a

format specified in the applicable construction contract may be used.

Results of the electronic equipment ground resistance measurements

shall be recorded. A suggested format similar to Format II, Outside

Plant Acceptance Tests--Trunk Circuits, in Sec. 1755.407 or a format

specified in the applicable construction contract may be used. Data

showing approximate moisture content of the soil at the time of

measurement, the temperature, the type of soil and a description of the

test equipment used shall also be included.

(g) Probable causes for nonconformance. Refer to RUS Bulletin

1751F-802, ``Electrical Protection Grounding Fundamentals,'' and

Telecommunications Engineering and Construction Manual (TE&CM) Section

810, ``Electrical Protection of Electronic Analog and Digital Central

Office Equipment,'' for possible causes of nonconformance and suggested

methods for corrective action.

Sec. 1755.403 Copper cable telecommunications plant measurements.

(a) Shield or shield/armor continuity. (1) Tests and measurements

shall be made to ensure that cable shields or shield/armors are

electrically continuous. There are two areas of concern. The first is

shield or shield/armor bonding within a pedestal or splice and the

second is shield or shield/armor continuity between pedestals or

splices.

(2) Measurement techniques outlined here for verification of shield

or shield/armor continuity are applicable to buried cable plant.

Measurements of shield continuity between splices in aerial cable plant

should be made prior to completion of splicing. Conclusive results

cannot be obtained on aerial plant after all bonds have been completed

to the supporting strand, multigrounded neutral, etc.

(3) Method of measurement. (i) The shield or shield/armor

resistance measurements shall be made between pedestals or splices

using either a Wheatstone bridge or a volt-ohm meter. For loaded plant,

measurements shall be made on cable lengths that do not exceed one load

section. For nonloaded plant, measurements shall be made on cable

lengths that do not exceed 5,000 feet (ft) (1,524 meters (m)). All

bonding wires shall be removed from the bonding lugs at the far end of

the cable section to be measured. The step-by-step measurement

procedure shall be as shown in Figure 2.

(ii) Cable shield or shield/armor continuity within pedestals or

splices shall be measured with a cable shield splice continuity test

set. The step-by-step measurement procedure outlined in the

manufacturer's operating instructions for the specific test equipment

being used shall be followed.

(4) Test equipment. (i) The test equipment for measuring cable

shield or shield/armor resistance between pedestals or splices is shown

in Figure 2 as follows:

BILLING CODE 3410-15-P

[[Page 23963]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.024

BILLING CODE 3410-15-C

[[Page 23964]]

(ii) A cable shield splice continuity tester shall be used to

measure shield or shield/armor continuity within pedestals or splices.

(5) Applicable results. (i) The shield or shield/armor resistance

per 1000 ft and per kilometer (km) for cable diameters and types of

shielding materials are given in Table 1 (English Units) and Table 2

(Metric Units), respectively as follows:

Table 1.--Shield Resistance @ 68 deg.F (20 deg.C) Cable Diameters Versus Shield Types

[English Units]

----------------------------------------------------------------------------------------------------------------

Nominal resistance ohm/1000 ft.

Outside diameter inches (in.) -----------------------------------------------------------------------------

A B C D E F

----------------------------------------------------------------------------------------------------------------

0.40-0.49......................... 0.77 1.54 1.65 1.96 2.30 5.51

0.50-0.59......................... 0.64 1.28 1.37 1.63 1.91 4.58

0.60-0.69......................... 0.51 1.03 1.10 1.31 1.53 3.67

0.70-0.79......................... 0.44 0.88 0.94 ........... 1.31 3.14

0.80-0.89......................... 0.38 0.77 0.82 ........... 1.14 2.74

0.90-0.99......................... 0.35 0.69 0.74 ........... 1.03 2.47

1.00-1.09......................... 0.31 0.62 0.66 ........... 0.92 2.20

1.10-1.19......................... 0.28 0.56 0.60 ........... 0.84 2.00

1.20-1.29......................... 0.26 0.51 0.55 ........... 0.77 1.84

1.30-1.39......................... 0.24 0.48 0.51 ........... 0.71 1.70

1.40-1.49......................... 0.22 0.44 0.47 ........... 0.65 1.57

1.50-1.59......................... 0.21 0.41 0.44 ........... 0.61 1.47

1.60-1.69......................... 0.19 0.38 0.41 ........... 0.57 1.37

1.70-1.79......................... 0.18 0.37 0.39 ........... 0.54 1.30

1.80-1.89......................... 0.17 0.35 0.37 ........... 0.51 1.24

1.90-1.99......................... 0.16 0.33 0.35 ........... 0.49 1.17

2.00-2.09......................... 0.15 0.31 0.33 ........... 0.46 1.10

2.10-2.19......................... 0.15 0.29 0.31 ........... 0.43 1.03

2.20-2.29......................... 0.14 0.28 0.30 ........... 0.42 1.00

2.30-2.39......................... 0.14 0.27 0.29 ........... 0.40 0.97

2.40-2.49......................... 0.13 0.25 0.27 ........... 0.38 0.90

2.50-2.59......................... 0.12 0.24 0.26 ........... 0.36 0.87

2.60-2.69......................... 0.12 0.23 0.25 ........... 0.35 0.83

2.70-2.79......................... 0.11 0.22 0.24 ........... 0.33 0.80

2.80-2.89......................... 0.11 0.22 0.24 ........... 0.33 0.80

2.90-2.99......................... 0.11 0.22 0.23 ........... 0.32 0.77

3.00-3.09......................... 0.10 0.21 0.22 ........... 0.31 0.73

3.10-3.19......................... 0.10 0.20 0.21 ........... 0.29 0.70

3.20-3.29......................... 0.10 0.20 0.21 ........... 0.29 0.70

3.30-3.39......................... 0.09 0.19 0.20 ........... 0.28 0.67

3.40-3.49......................... 0.09 0.18 0.19 ........... 0.26 0.63

3.50-3.59......................... 0.09 0.18 0.19 ........... 0.26 0.63

3.60-3.69......................... 0.08 0.17 0.18 ........... 0.25 0.60

3.70-3.79......................... 0.08 0.17 0.18 ........... 0.25 0.60

3.80-3.89......................... 0.08 0.16 0.17 ........... 0.24 0.57

3.90-3.99......................... 0.08 0.16 0.17 ........... 0.24 0.57

4.00-4.99......................... 0.07 0.15 0.16 ........... 0.22 0.53

----------------------------------------------------------------------------------------------------------------

Where: Column A-10 mil Copper shield.

Column B--5 mil Copper shield.

Column C--8 mil Coated Aluminum and 8 mil Coated Aluminum/6 mil Coated Steel shields.

Column D--7 mil Alloy 194 shield.

Column E--6 mil Alloy 194 and 6 mil Copper Clad Stainless Steel shields.

Column F--5 mil Copper Clad Stainless Steel and 5 mil Copper Clad Alloy Steel shields.

Table 2.--Shield Resistance @ 68 deg.F (20 deg.C) Cable Diameters Versus Shield Types

[Metric Units]

----------------------------------------------------------------------------------------------------------------

Nominal Resistance ohm/km

Outside diameter millimeters (mm) -----------------------------------------------------------------------------

A B C D E F

----------------------------------------------------------------------------------------------------------------

10.2--12.5........................ 2.53 5.05 5.41 6.43 7.55 18.08

12.7--15.0........................ 2.10 4.20 4.49 5.35 6.27 15.03

15.2--17.5........................ 1.67 3.38 3.61 4.30 5.02 12.04

17.8--20.1........................ 1.44 2.89 3.08 ........... 4.30 10.30

20.3--22.6........................ 1.25 2.53 2.69 ........... 3.74 8.99

22.9--25.1........................ 1.15 2.26 2.43 ........... 3.38 8.10

25.4--27.7........................ 1.02 2.03 2.16 ........... 3.02 7.22

27.9--30.2........................ 0.92 1.84 1.97 ........... 2.76 6.56

30.5--32.8........................ 0.85 1.67 1.80 ........... 2.53 6.04

33.0--35.3........................ 0.79 1.57 1.67 ........... 2.33 5.58

35.6--37.8........................ 0.72 1.44 1.54 ........... 2.13 5.15

38.1--40.4........................ 0.69 1.34 1.44 ........... 2.00 4.82

[[Page 23965]]

40.6--42.9........................ 0.62 1.25 1.34 ........... 1.87 4.49

43.2--45.5........................ 0.59 1.21 1.28 ........... 1.77 4.26

45.7--48.0........................ 0.56 1.15 1.21 ........... 1.67 4.07

48.3--50.5........................ 0.52 1.08 1.15 ........... 1.61 3.84

50.8--53.1........................ 0.49 1.02 1.08 ........... 1.51 3.61

53.3--55.6........................ 0.49 0.95 1.02 ........... 1.41 3.38

55.9--58.2........................ 0.46 0.92 0.98 ........... 1.38 3.28

58.4--60.7........................ 0.46 0.89 0.95 ........... 1.31 3.18

61.0--63.2........................ 0.43 0.82 0.89 ........... 1.25 2.95

63.5--65.8........................ 0.39 0.79 0.85 ........... 1.18 2.85

66.0--68.3........................ 0.39 0.75 0.82 ........... 1.15 2.72

68.6--70.9........................ 0.36 0.72 0.79 ........... 1.08 2.62

71.1--73.4........................ 0.36 0.72 0.79 ........... 1.08 2.62

73.7--75.9........................ 0.36 0.72 0.75 ........... 1.05 2.53

76.2--78.5........................ 0.33 0.69 0.72 ........... 1.02 2.39

78.7--81.0........................ 0.33 0.66 0.69 ........... 0.95 2.30

81.3--83.6........................ 0.33 0.66 0.69 ........... 0.95 2.30

83.6--86.1........................ 0.29 0.62 0.66 ........... 0.92 2.20

86.4--88.6........................ 0.29 0.59 0.62 ........... 0.85 2.07

88.9--91.2........................ 0.29 0.59 0.62 ........... 0.85 2.07

91.4--93.7........................ 0.26 0.56 0.59 ........... 0.82 1.97

94.0--96.3........................ 0.26 0.56 0.59 ........... 0.82 1.97

96.5--98.8........................ 0.26 0.52 0.56 ........... 0.79 1.87

99.1--101.3....................... 0.26 0.52 0.56 ........... 0.79 1.87

101.6--103.9...................... 0.23 0.49 0.52 ........... 0.72 1.74

----------------------------------------------------------------------------------------------------------------

Where: Column A--10 mil Copper shield.

Column B--5 mil Copper shield.

Column C--8 mil Coated Aluminum and 8 mil Coated Aluminum/6 mil Coated Steel shields.

Column D--7 mil Alloy 194 shield.

Column E--6 mil Alloy 194 and 6 mil Copper Clad Stainless Steel shields.

Column F--5 mil Copper Clad Stainless Steel and 5 mil Copper Clad Alloy Steel shields.

(ii) All values of shield and shield/armor resistance provided in

Tables 1 and 2 in (a)(5)(i) of this section are considered

approximations. If the measured value corrected to 68 deg.F (20 deg.C)

is within 30 percent (%) of the value shown in Table 1 or

2, the shield and shield/armor shall be assumed to be continuous.

(iii) To correct the measured shield resistance to the reference

temperature of 68 deg.F (20 deg.C) use the following formulae:

R68=Rt/[1+A(t-68)] for English Units

R20=Rt/[1+A(t-20)] for Metric Units

Where:

R68=Shield resistance corrected to 68 deg.F in ohms.

R20=Shield resistance corrected to 20 deg.C in ohms.

Rt=Shield resistance at measurement temperature in ohms.

A=Temperature coefficient of the shield tape.

t=Measurement temperature in deg.F or ( deg.C).

(iv) The temperature coefficients (A) for the shield tapes to be

used in the formulae referenced in paragraph (a)(5)(iii) of this

section are as follows:

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

Metric units;

(B) 8 mil coated aluminum and 8 mil coated aluminum/6 mil coated

steel = 0.0022 for English units and 0.0040 for Metric units;

(C) 5 mil copper clad stainless steel and 5 mil copper clad alloy

steel = 0.0024 for English units and 0.0044 for Metric units;

(D) 6 mil copper clad stainless steel = 0.0019 for English units

and 0.0035 for Metric units; and

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

Metric units.

(v) When utilizing shield continuity testers to measure shield and

shield/armor continuity within pedestals or splices, refer to the

manufacturer's published information covering the specific test

equipment to be used and for anticipated results.

(6) Data record. Measurement data from shield continuity tests

shall be recorded together with anticipated Table 1 or 2 values (see

paragraph (a)(5)(i) of this section) in an appropriate format to permit

comparison. The recorded data shall include specific location, cable

size, cable type, type of shield or shield/armor, if known, etc.

(7) Probable causes for nonconformance. Among probable causes for

nonconformance are broken or damaged shields or shield/armors, bad

bonding harnesses, poorly connected bonding clamps, loose bonding lugs,

etc.

(b) Conductor continuity. After placement of all cable and wire

plant has been completed and joined together in continuous lengths,

tests shall be made to ascertain that all pairs are free from grounds,

shorts, crosses, and opens, except for those pairs indicated as being

defective by the cable manufacturer. The tests for grounds, shorts,

crosses, and opens are not separate tests, but are inherent in other

acceptance tests discussed in this section. The test for grounds,

shorts, and crosses is inherent when conductor insulation resistance

measurements are conducted per paragraph (c) of this section, while

tests for opens are inherent when tests are conducted for loop

resistance, insertion loss, noise, or return loss measurements, per

paragraphs (d), (e), or (f) of this section. The borrower shall make

certain that all defective pairs are corrected, except

[[Page 23966]]

those noted as defective by the cable manufacturer in accordance with

the marking provisions of the applicable cable and wire specifications.

All defective pairs that are not corrected shall be reported in writing

with details of the corrective measures attempted.

(c) Dc insulation resistance (IR) measurement. (1) IR measurements

shall be made on completed lengths of insulated cable and wire plant.

(2) Method of measurement. (i) The IR measurement shall be made

between each conductor and all other conductors, sheath, shield and/or

shield/armor, and/or support wire electrically connected together and

to the main distributing frame (MDF) ground. The measurement shall be

made from the central office with the entire length of the cable under

test and, where used with all protectors and load coils connected. For

COs containing solid state arresters, the solid state arresters shall

be removed before making the IR measurements. Field mounted voice

frequency repeaters, where used, may be left connected for the IR test

but all carrier frequency equipment, including carrier repeaters and

terminals, shall be disconnected. Pairs used to feed power remote from

the CO shall have the power disconnected and the tip and ring

conductors shall be opened before making IR tests. All conductors shall

be opened at the far end of the cable being measured.

(ii) IR tests are normally made from the MDF with all CO equipment

disconnected at the MDF, but this test may be made on new cables at

field locations before they are spliced to existing cables. The method

of measurement shall be as shown in Figure 3 as follows:

BILLING CODE 3410-15-P

[[Page 23967]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.025

BILLING CODE 3410-15-C

[[Page 23968]]

(iii) If the IR of the conductor cannot be measured because of

breakdown of lightning arresters by the test voltage, the arrester

units shall be removed and the conductor IR retested. If the IR then

meets the minimum requirements, the conductor will be considered

satisfactory. Immediately following the IR tests, all arrester units

which have been removed shall be reinstalled.

(3) Test equipment. (i) IR measurements shall be made with either

an insulation resistance test set or a direct current (dc) bridge type

megohmmeter.

(ii) The IR test set shall have an output voltage not to exceed 500

volts dc and shall be of the hand cranked or battery operated type.

(iii) The dc bridge type megohmmeter, which may be alternating

current (ac) powered, shall have scales and multiplier which make it

possible to accurately read IR from 1 megohm to 1 gigohm. The voltage

applied to the conductors under test shall not exceed ``250 volts dc''

when using an instrument having adjustable test voltage levels. This

will help to prevent breakdown of lightning arresters.

(4) Applicable results. (i) For all new insulated cable or wire

facilities, the expected IR levels are normally greater than 1,000 to

2,000 megohm-mile (1,609 to 3,218 megohm-km). A value of 500 megohm-

mile (805 megohm-km) at 68 deg.F (20 deg.C) shall be the minimum

acceptable value of IR. IR varies inversely with the length and the

temperature.

(ii) The megohm-mile (megohm-km) value for a conductor may be

computed by multiplying the actual scale reading in megohms on the test

set by the length in miles (km) of the conductor under test.

(iii) The objective insulation resistance may be determined by

dividing 500 by the length in miles (805 by the length in km) of the

cable or wire conductor being tested. The resulting value shall be the

minimum acceptable meter scale reading in megohms.

(iv) Due to the differences between various insulating materials

and filling compounds used in manufacturing cable or wire, it is

impractical to provide simple factors to predict the magnitude of

variation in insulation resistance due to temperature. The variation

can, however, be substantial for wide excursions in temperature from

the ambient temperature of 68 deg.F (20 deg.C).

(v) Borrowers should be certain that tip and ring IR measurements

of each pair are approximately the same. Borrowers should also be

certain that IR measurements are similar for cable or wire sections of

similar length and cable or wire type. If some pairs measure

significantly lower, borrowers should attempt to improve these pairs in

accordance with cable manufacturer's recommendations.

Note: Only the megohm-mile (megohm-km) requirement shall be

cause for rejection, not individual measurement differences.

(5) Data record. The measurement data shall be recorded. Suggested

formats similar to Format I, Outside Plant Acceptance Tests--Subscriber

Loops, or Format II, Outside Plant Acceptance Tests--Trunk Circuits, in

Sec. 1755.407 or formats specified in the applicable construction

contract may be used.

(6) Probable causes for nonconformance. (i) When an IR measurement

is below 500 megohm-mile (805 megohm-km), the cable or wire temperature

at the time of testing must then be taken into consideration. If this

temperature is well above 68 deg.F (20 deg.C), the measurement shall

be disregarded and the cable or wire shall be remeasured at a time when

the temperature is approximately 68 deg.F (20 deg.C). If the result

is then 500 megohm-mile (805 megohm-km) or greater, the cable or wire

shall be considered satisfactory.

(ii) Should the cable or wire fail to meet the 500 megohm-mile (805

megohm-km) requirement when the temperature is known to be

approximately 68 deg.F (20 deg.C) there is not yet justification for

rejection of the cable or wire. Protectors, lightning arresters, etc.,

may be a source of low insulation resistance. These devices shall be

removed from the cable or wire and the cable or wire IR measurement

shall be repeated. If the result is acceptable, the cable or wire shall

be considered acceptable. The removed devices which caused the low

insulation resistance value shall be identified and replaced, if found

defective.

(iii) When the cable or wire alone is still found to be below the

500 megohm-mile (805 megohm-km) requirement after completing the steps

in paragraph (c)(6)(i) and/or paragraph (c)(6)(ii) of this section, the

test shall be repeated to measure the cable or wire in sections to

isolate the piece(s) of cable or wire responsible. The cable or wire

section(s) that is found to be below the 500 megohm-mile (805 megohm-

km) requirement shall be either repaired in accordance with the cable

or wire manufacturer's recommended procedure or shall be replaced as

directed by the borrower.

(d) Dc loop resistance and dc resistance unbalance measurement. (1)

When specified by the borrower, dc loop resistance and dc resistance

unbalance measurements shall be made on all cable pairs used as trunk

circuits. The dc loop resistance and dc resistance unbalance

measurements shall be made between CO locations. Measurements shall

include all components of the cable path.

(2) Dc loop resistance and dc resistance unbalance measurements

shall be made on all cable pairs used as subscriber loop circuits when:

(i) Specified by the borrower;

(ii) A large number of long loops terminate at one location

(similar to trunk circuits); or

(iii) Circuit balance is less than 60 dB when computed from noise

measurements as described in paragraph (e) of this section.

(3) Dc resistance unbalance is controlled to the maximum possible

degree by the cable specification. Allowable random unbalance is

specified between tip and ring conductors within each reel. Further

random patterns should occur when the cable conductor size changes.

Cable meeting the unbalance requirements of the cable specification may

under some conditions result in unacceptable noise levels as discussed

in paragraph (d)(6)(iii) of this section.

(4) Method of measurement. The method of measurement shall be as

detailed in Figures 4 and 5.

(5) Test equipment. The test equipment is shown in Figures 4 and 5

as follows:

BILLING CODE 3410-15-P

[[Page 23969]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.026

[[Page 23970]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.027

BILLING CODE 3410-15-C

[[Page 23971]]

(6) Applicable results. (i) The measured dc loop resistance shall

be within 5% of the calculated dc loop resistance when

corrected for temperature.

(ii) The calculated dc loop resistance is computed as follows:

(A) Multiply the length of each different gauge by the applicable

resistance per unit length as shown in Table 3 as follows:

Table 3.--DC Loop Resistance @ 68 deg.F (20 deg.C)

------------------------------------------------------------------------

Loop resistance

American wire gauge (AWG) -------------------------------

ohms/1000 ft ohms/km

------------------------------------------------------------------------

19...................................... 16.1 52.8

22...................................... 32.4 106.3

24...................................... 51.9 170.3

26...................................... 83.3 273.3

------------------------------------------------------------------------

(B) Add the individual resistances for each gauge to give the total

calculated dc loop resistance at a temperature of 68 deg.F (20 deg.C).

(C) Correct the total calculated dc loop resistance at the

temperature of 68 deg.F (20 deg.C) to the measurement temperature by

the following formulae:

Rt=R68 x [1+0.0022 x t--68)] for English Units

Rt=R20 x [1+0.0040 x (t--20)] for Metric Units

Where:

Rt = Loop resistance at the measurement temperature in ohms.

R68 = Loop resistance at a temperature of 68 deg.F in ohms.

R20 = Loop resistance at a temperature of 20 deg.C in ohms.

t = Measurement temperature in deg.F or ( deg.C).

(D) Compare the calculated dc loop resistance at the measurement

temperature to the measured dc loop resistance to determine compliance

with the requirement specified in paragraph (d)(6)(i) of this section.

(iii) Resistance varies directly with temperature change. For

copper conductor cables, the dc resistance changes by 1%

for every 5 deg.F (2.8 deg.C) change in temperature from

68 deg.F (20 deg.C).

(iv) The dc resistance unbalance between the individual conductors

of a pair shall not exceed that value which will result in a circuit

balance of less than 60 dB when computed from noise measurements as

described in paragraph (e) of this section. It is impractical to

establish a precise limit for overall circuit dc resistance unbalance

due to the factors controlling its contribution to circuit noise. These

factors include location of the resistance unbalance in relation to a

low impedance path to ground (close to the central office) and the

magnitude of unbalance in short lengths of cable making up the total

circuit length. The objective is to obtain the minimum unbalance

throughout the entire circuit when it is ascertained through noise

measurements that dc resistance unbalance may be contributing to poor

cable balance.

(v) Pairs with poor noise balance may be improved by reversing tip

and ring conductors of pairs at cable splices. Where dc resistance

unbalances are systematic over the total trunk circuit or loop circuit

length, tip and ring reversals may be made at frequent intervals. Where

the unbalances are concentrated in a shorter section of cable, only one

tip and ring reversal should be required. Concentrated dc resistance

unbalance produces maximum circuit noise when located adjacent to the

central office. Concentrated dc resistance unbalance will contribute to

overall circuit noise at a point approximately two-thirds (\2/3\) of

the distance to the subscriber. All deliberate tip and ring reversals

shall be tagged and identified to prevent plant personnel from removing

the reversals when resplicing these connections in the future. The

number of tip and ring reversals shall be held to a minimum.

(vi) A systematic dc resistance unbalance can sometimes be

accompanied by other cable parameters that are marginal. Among these

are pair-to-pair capacitance unbalance, capacitance unbalance-to-

ground, and 150 kilohertz (kHz) crosstalk loss. Engineering judgment

has to be applied in each case. Rejection of cable for excessive dc

resistance unbalance shall only apply to a single reel length, or

shorter.

[[Page 23972]]

(7) Data record. The measurement data for dc loop resistance and dc

resistance unbalance shall be recorded. Suggested formats similar to

Format I for subscriber loops and Format II for trunk circuits in

Sec. 1755.407 or formats specified in the applicable construction

contract may be used.

(8) Probable causes for nonconformance. Dc loop resistance and dc

resistance unbalance are usually the result of the resistance of

individual conductors used in the manufacture of the cable. Resistance

unbalance can be worsened by defective splicing of the conductors

(splicing connectors, improper crimping tool, etc.).

(e) Subscriber loop measurement (loop checking). (1) When specified

by the borrower, insertion loss and noise measurements shall be

performed on subscriber loops after connection of a line circuit to the

loop by the one person method using loop checking equipment from the

customer access location. For this method, the central office should be

equipped with a 900 ohm plus two microfarad quiet termination and a

milliwatt generator having the required test frequencies; or a portable

milliwatt generator having the desired frequencies may be used,

especially, where several small offices are involved.

(2) At a minimum, insertion loss and frequency response of

subscriber loop plant shall be measured at 1,000, 1,700, 2,300, and

2,800 Hertz (Hz). When additional testing frequencies are desired, the

additional frequencies shall be specified in the applicable

construction contract.

(3) Measurements of insertion loss and noise shall be made on five

percent or more of the pairs. A minimum of five pairs shall be tested

on each route. Pairs shall be selected on a random basis with greater

consideration in the selection given to the longer loops. Consideration

shall be given to measuring a large percentage, up to 100 percent, of

all loops.

(4) Method of measurement--(i) Insertion loss. The step-by-step

measurement procedure shall be as shown in Figure 6. The output level

of the milliwatt generator tones shall be determined prior to leaving

the CO. This shall be accomplished by dialing the milliwatt generator

number from a spare line at the MDF and measuring with the same

equipment to be used in the tests at customer access locations. The

output levels shall be recorded for reference later. Insertion loss

measurements shall be made across the tip and ring terminals of the

pair under test. Figure 6 is as follows:

BILLING CODE 3410-15-P

[[Page 23973]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.028

BILLING CODE 3410-15-C

[[Page 23974]]

(ii) Noise. The step-by-step measurement procedure shall be as

shown in Figure 7. Prior to leaving the CO for testing, dial the 900

ohm plus two microfarad quiet termination from a spare pair and measure

the termination to determine that it actually is quiet. Circuit noise

(noise-metallic) shall be measured at the customer access location

across the tip and ring terminals of the pair under test. Power

influence (direct reading with loop checking equipment) shall be

measured at the customer access location from tip and ring conductors-

to-ground (this connection is completed via the test unit). The power

influence measurement includes the entire talking connection from the

quiet termination to the customer. (That is, the power influence

measurement includes all the CO equipment which normally makes up the

connection.) Figure 7 is as follows:

BILLING CODE 3410-15-P

[[Page 23975]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.029

BILLING CODE 3410-15-C

[[Page 23976]]

(5) Test equipment. (i) Loop checking equipment which is available

from several manufacturers may be used for these measurements. The

equipment should have the capability of measuring loop current,

insertion loss, circuit noise (NM) and power influence (PI). The test

equipment manufacturer's operating instructions shall be followed.

(ii) There should be no measurable transmission loss when testing

through loop extenders.

(6) Applicable results--(i) Insertion loss. (A) For D66 loaded

cables (a specific loading scheme using a 66 millihenry inductor spaced

nominally at 4,500 ft [1,371 m] intervals) measured at a point one-half

section length beyond the last load point, the measured nonrepeated

insertion loss shall be within 10% at 1000, 1700, 2300,

and 2800 Hz, 15% at 3400 Hz and 20% at 4000

Hz of the calculated insertion loss at the same frequencies and

temperature.

(B) For H88 loaded cables (a specific loading scheme using an 88

millihenry inductor spaced nominally at 6,000 ft [1,829 m] intervals)

measured at a point one-half section length beyond the last load point,

the measured nonrepeatered insertion loss shall be within

10% at 1000, 1700, and 2300 Hz, 15% at 2800 Hz, and

20% at 3400 Hz of the calculated insertion loss at the

same frequencies and temperature.

(C) For nonloaded cables, the measured insertion loss shall be

within 10% at 1000, 1700, 2300, and 2800 Hz,

15% at 3400 Hz and 20% at 4000 Hz of the calculated

insertion loss at the same frequencies and temperature.

(D) For loaded cables, the calculated loss at each desired

frequency shall be computed as follows:

(1) Multiply the length in miles (km) of each different gauge in

the loaded portion of the loop (between the office and a point one-half

load section beyond the furthest load point) by the applicable decibel

(dB)/mile (dB/km) value shown in Table 4 or 5. This loss represents the

total loss for each gauge in the loaded portion of the loop;

(2) Multiply the length in miles (km) of each different gauge in

the end section or nonloaded portion of the cable (beyond a point one-

half load section beyond the furthest load point) by the applicable dB/

mile (dB/km) value shown in Table 6. This loss represents the total

loss for each gauge in the nonloaded portion of the loop; and

(3) The total calculated insertion loss is computed by adding the

individual losses determined in paragraphs (e)(6)(i)(D)(1) and

(e)(6)(i)(D)(2) of this section.

(E) For nonloaded cables, the calculated loss at each desired

frequency shall be computed by multiplying the length in miles (km) of

each different gauge by the applicable dB/mile (dB/km) value shown in

Table 6 and then adding the individual losses for each gauge to

determine the total calculated insertion loss for the nonloaded loop.

(F) The attenuation information in Tables 4, 5, and 6 are based on

a cable temperature of 68 deg.F (20 deg.C). Insertion loss varies

directly with temperature. To convert measured losses for loaded cables

to a different temperature, use the following value for copper

conductors: For each 5 deg.F ( 2.8 deg.C)

change in the temperature from 68 deg.F (20 deg.C), change the

insertion loss at any frequency by 1%. To convert measured

losses for nonloaded cables to a different temperature, use the

following value for copper conductors: For each 10 deg.F

(5.6 deg.C) change in the temperature from 68 deg.F (20

deg.C), change the insertion loss at any frequency by 1%.

Tables 4, 5, and 6 are as follows:

Table 4.--Frequency Attenuation @ 68 deg.F (20 deg.C) D66 Loaded Exchange Cables 83 nanofarad (nF)/mile (52 nF/

km) (See Note)

----------------------------------------------------------------------------------------------------------------

Attenuation dB/mile (dB/km) AWG

Frequency (Hz) -------------------------------------------------------------------

19 22 24 26

----------------------------------------------------------------------------------------------------------------

200......................................... 0.41 (0.26) 0.67 (0.42) 0.90 (0.56) 1.21 (0.75)

400......................................... 0.43 (0.26) 0.77 (0.48) 1.09 (0.68) 1.53 (0.95)

600......................................... 0.44 (0.27) 0.80 (0.49) 1.17 (0.73) 1.70 (1.06)

800......................................... 0.44 (0.27) 0.81 (0.50) 1.21 (0.75) 1.80 (1.12)

1000........................................ 0.44 (0.27) 0.82 (0.51) 1.23 (0.76) 1.86 (1.15)

1200........................................ 0.45 (0.28) 0.83 (0.52) 1.24 (0.77) 1.91 (1.19)

1400........................................ 0.45 (0.28) 0.83 (0.52) 1.26 (0.78) 1.94 (1.20)

1600........................................ 0.45 (0.28) 0.84 (0.52) 1.26 (0.78) 1.96 (1.22)

1800........................................ 0.45 (0.28) 0.84 (0.52) 1.27 (0.78) 1.98 (1.23)

2000........................................ 0.46 (0.29) 0.85 (0.53) 1.28 (0.79) 1.99 (1.24)

2200........................................ 0.46 (0.29) 0.85 (0.53) 1.29 (0.80) 2.01 (1.25)

2400........................................ 0.47 (0.29) 0.86 (0.53) 1.30 (0.81) 2.02 (1.26)

2600........................................ 0.47 (0.29) 0.87 (0.54) 1.31 (0.81) 2.04 (1.27)

2800........................................ 0.48 (0.30) 0.88 (0.55) 1.32 (0.82) 2.07 (1.29)

3000........................................ 0.49 (0.30) 0.89 (0.55) 1.34 (0.83) 2.10 (1.30)

3200........................................ 0.50 (0.31) 0.91 (0.57) 1.36 (0.84) 2.13 (1.32)

3400........................................ 0.52 (0.32) 0.93 (0.58) 1.40 (0.87) 2.19 (1.36)

3600........................................ 0.54 (0.34) 0.97 (0.60) 1.45 (0.90) 2.26 (1.40)

3800........................................ 0.57 (0.35) 1.02 (0.63) 1.52 (0.94) 2.36 (1.47)

4000........................................ 0.62 (0.38) 1.10 (0.68) 1.63 (1.01) 2.53 (1.57)

----------------------------------------------------------------------------------------------------------------

Note: Between end-section lengths of 2,250 ft (686 m) for D66 loading.

Table 5.--Frequency Attenuation @ 68 deg.F (20 deg.C) H88 Loaded Exchange Cables 83 nF/ mile (52 nF/km) (See

Note)

----------------------------------------------------------------------------------------------------------------

Attenuation dB/mile (dB/km) AWG

Frequency (Hz) -------------------------------------------------------------------

19 22 24 26

----------------------------------------------------------------------------------------------------------------

200......................................... 0.40 (0.25) 0.66 (0.41) 0.90 (0.56) 1.20 (0.75)

[[Page 23977]]

400......................................... 0.42 (0.26) 0.76 (0.47) 1.08 (0.67) 1.53 (0.95)

600......................................... 0.43 (0.27) 0.79 (0.49) 1.16 (0.72) 1.70 (1.06)

800......................................... 0.43 (0.27) 0.80 (0.50) 1.20 (0.75) 1.80 (1.12)

1000........................................ 0.43 (0.27) 0.81 (0.50) 1.23 (0.76) 1.86 (1.15)

1200........................................ 0.44 (0.27) 0.82 (0.51) 1.24 (0.77) 1.91 (1.19)

1400........................................ 0.44 (0.28) 0.82 (0.51) 1.25 (0.78) 1.94 (1.20)

1600........................................ 0.44 (0.27) 0.83 (0.52) 1.26 (0.78) 1.97 (1.22)

1800........................................ 0.45 (0.28) 0.84 (0.52) 1.28 (0.79) 1.99 (1.24)

2000........................................ 0.46 (0.29) 0.85 (0.53) 1.29 (0.80) 2.02 (1.26)

2200........................................ 0.47 (0.29) 0.86 (0.53) 1.31 (0.81) 2.06 (1.28)

2400........................................ 0.48 (0.30) 0.89 (0.55) 1.34 (0.83) 2.10 (1.30)

2600........................................ 0.50 (0.31) 0.92 (0.57) 1.39 (0.86) 2.18 (1.35)

2800........................................ 0.53 (0.33) 0.97 (0.60) 1.47 (0.91) 2.29 (1.42)

3000........................................ 0.59 (0.37) 1.07 (0.66) 1.60 (0.99) 2.48 (1.54)

3200........................................ 0.71 (0.44) 1.26 (0.78) 1.87 (1.16) 2.86 (1.78)

3400........................................ 1.14 (0.71) 1.91 (1.19) 2.64 (1.64) 3.71 (2.30)

3600........................................ 4.07 (2.53) 4.31 (2.68) 4.65 (2.90) 5.30 (3.29)

3800........................................ 6.49 (4.03) 6.57 (4.08) 6.72 (4.18) 7.06 (4.39)

4000........................................ 8.22 (5.11) 8.27 (5.14) 8.36 (5.19) 8.58 (5.33)

----------------------------------------------------------------------------------------------------------------

Note: Between end-section lengths of 3,000 ft (914 m) for H88 loading.

Table 6.--Frequency Attenuation @ 68 deg.F (20 deg.C) Nonloaded Exchange Cables 83 nF/ mile (52 nF/km) AWG

----------------------------------------------------------------------------------------------------------------

Attenuation dB/mile (dB/km) AWG

Frequency (Hz) -------------------------------------------------------------------

19 22 24 26

----------------------------------------------------------------------------------------------------------------

200......................................... 0.58 (0.36) 0.82 (0.51) 1.03 (0.64) 1.30 (0.81)

400......................................... 0.81 (0.51) 1.15 (0.71) 1.45 (0.90) 1.84 (1.14)

600......................................... 0.98 (0.61) 1.41 (0.87) 1.77 (1.10) 2.26 (1.40)

800......................................... 1.13 (0.70) 1.62 (1.01) 2.04 (1.27) 2.60 (1.61)

1000........................................ 1.25 (0.78) 1.80 (1.12) 2.28 (1.42) 2.90 (1.80)

1200........................................ 1.36 (0.84) 1.97 (1.22) 2.50 (1.55) 3.17 (1.97)

1400........................................ 1.46 (0.91) 2.12 (1.32) 2.69 (1.67) 3.42 (2.12)

1600........................................ 1.55 (0.96) 2.26 (1.40) 2.87 (1.78) 3.65 (2.27)

1800........................................ 1.63 (1.01) 2.39 (1.48) 3.04 (1.89) 3.87 (2.40)

2000........................................ 1.71 (1.06) 2.51 (1.56) 3.20 (1.99) 4.08 (2.53)

2200........................................ 1.78 (1.11) 2.62 (1.63) 3.35 (2.08) 4.27 (2.65)

2400........................................ 1.85 (1.15) 2.73 (1.70) 3.49 (2.17) 4.45 (2.76)

2600........................................ 1.91 (1.19) 2.83 (1.76) 3.62 (2.25) 4.63 (2.88)

2800........................................ 1.97 (1.22) 2.93 (1.82) 3.75 (2.33) 4.80 (2.98)

3000........................................ 2.03 (1.26) 3.02 (1.88) 3.88 (2.41) 4.96 (3.08)

3200........................................ 2.08 (1.29) 3.11 (1.93) 4.00 (2.48) 5.12 (3.18)

3400........................................ 2.13 (1.32) 3.19 (1.98) 4.11 (2.55) 5.27 (3.27)

3600........................................ 2.18 (1.35) 3.28 (2.04) 4.22 (2.62) 5.41 (3.36)

3800........................................ 2.22 (1.38) 3.36 (2.09) 4.33 (2.69) 5.55 (3.45)

4000........................................ 2.27 (1.41) 3.43 (2.13) 4.43 (2.75) 5.69 (3.53)

----------------------------------------------------------------------------------------------------------------

(G) For loaded subscriber loops, the 1 kHz loss shall be

approximately 0.45 dB per 100 ohms of measured dc loop resistance. This

loss shall be the measured loss less the net gain of any voice

frequency repeaters in the circuit. Testing shall also be conducted to

verify that the loss increases gradually as the frequency increases.

The loss on H88 loaded loops should be down only slightly at 2.8 kHz

but drop rapidly above 2.8 kHz. The loss on D66 loaded loops shall be

fairly constant to about 3.4 kHz and there shall be good response at

4.0 kHz. When voice frequency repeaters are in the circuit there will

be some frequency weighting in the build-out network and the loss at

the higher frequencies will be greater than for nonrepeatered loops.

(H) For nonloaded subscriber loops, the 1 kHz loss shall be

approximately 0.9 dB per 100 ohms of measured dc loop resistance.

Testing shall also be conducted to verify that the loss is

approximately a straight line function with no abrupt changes. The 3

kHz loss should be approximately 70% higher than the 1 kHz loss.

(ii) Noise. The principal objective related to circuit noise

(noise-metallic) and the acceptance of new plant is that circuit noise

levels be 20 dBrnc or less (decibels above reference noise, C-message

weighted (a weighting derived from listening tests, to indicate the

relative annoyance or speech impairment by an interfering signal of

frequency (f) as heard through a ``500-type'' telephone set)). For most

new, properly installed, plant construction, circuit noise will usually

be considerably less than 20 dBrnc unless there are unusually long

sections of telephone plant in parallel with electric power facilities

and/or power influence of paralleling electric facilities is abnormally

high. When circuit noise is

[[Page 23978]]

20 dBrnc or less, the loop plant shall be considered acceptable. When

measured circuit noise is greater than 20 dBrnc, loop plant shall still

be considered acceptable providing circuit balance (power influence

reading minus circuit noise readings) is 60 dB or greater and power

influence readings are 85 dBrnc or greater. When circuit noise is

greater than 20 dBrnc and circuit balance is less than 60 dB and/or

power influence is less than 85 dBrnc, loop plant shall not be

considered acceptable and the loop plant shall be remedied to make

circuit balance equal to or greater than 60 dB.

(7) Data record. Measurement data shall be recorded. A suggested

format similar to Format I for subscriber loops in Sec. 1755.407 or a

format specified in the applicable construction contract may be used.

(8) Probable causes for nonconformance.--(i) Insertion loss. Some

of the more common causes for failing to obtain the desired results may

be due to reversed load coil windings, missing load coils, bridge taps

between load coils, load coil spacing irregularities, excessive end

sections, cables having high or low mutual capacitance, load coils

having the wrong inductance, load coils inadvertently installed in

nonloaded loops, moisture or water in cable, split pairs, and

improperly spliced connections. The above factors can occur singularly

or in combination. Experience to date indicates that the most common

problems are missing load coils, reversed load coil windings or bridge

taps.

(ii) Noise. Some of the common causes for failing to obtain the

desired results may be due to high power influence from paralleling

electrical power systems, poor telephone circuit balance, discontinuous

cable shields, inadequate bonding and grounding of cable shields, high

capacitance unbalance-to-ground of the cable pairs, high dc loop

resistance unbalance, dc loop current less than 20 milliamperes, etc.

The above factors can occur singularly or in combination. See TE&CM

Section 451, Telephone Noise Measurement and Mitigation, for steps to

be taken in reducing telecommunications line noise.

(f) One-person open circuit measurement (subscriber loops). (1)

When specified by the borrower, open circuit measurements shall be made

on all loaded and nonloaded subscriber loops upon completion of the

cable work to verify that the plant is free from major impedance

irregularities.

(2) For loaded loops, open circuit measurements shall be made using

one of the following methods:

(i) Impedance or pulse return pattern, with cable pair trace

compared to that of an artificial line of the same length and gauge.

For best results, a level tracer or fault locator with dual trace

capability is required;

(ii) Return loss using a level tracer, with cable pair compared to

an artificial line of the same length and gauge connected in lieu of a

Precision Balance Network (PBN). This method can be made with level

tracers having only single trace capability; or

(iii) Open circuit structural return loss using a level tracer.

This method can be made with level tracer having only single trace

capability.

(3) Of the three methods suggested for loaded loops, the method

specified in paragraph (f)(2)(ii) of this section is the preferred

method because it can yield both qualitative and quantitative results.

The methods specified in paragraphs (f)(2)(i) and (f)(2)(iii) of this

section can be used as trouble shooting tools should irregularities be

found during testing.

(4) For nonloaded loops, open circuit measurements shall be made

using the method specified in paragraph (f)(2)(i) of this section.

(5) Method of measurement. Open circuit measurements shall be made

at the CO on each loaded and nonloaded pair across the tip and ring

terminals of the pair under test. All CO equipment shall be

disconnected at the MDF for this test. For loaded loops containing

voice frequency repeaters installed in the CO or field mounted, the

open circuit measurement shall be made after the repeaters have been

disconnected. Where field mounted repeaters are used, the open circuit

measurement shall be made at the repeater location in both directions.

(i) Impedance or pulse return pattern. The step-by-step measurement

procedure using the impedance or pulse return pattern for loaded and

nonloaded loops shall be as shown in Figure 8. An artificial line of

the same makeup as the cable to be tested shall be set up. The traces

of the impedance or pulse return pattern from the cable pair and the

artificial line shall be compared and should be essentially identical.

If the impedance or pulse return traces from the cable pair are

different than the artificial line trace, cable faults are possible.

When the cable pair trace indicates possible defects, the defects

should be identified and located. One method of identifying and

locating defects involves introducing faults into the artificial line

until its trace is identical with the cable trace.

(ii) Return loss balanced to artificial line. The step-by-step

measurement procedure using the return loss balanced to artificial line

for loaded loops shall be as shown in Figure 9. An artificial line of

the same makeup as the cable to be tested shall be set up. The

artificial line is connected to the external network terminals of the

test set. The cable pair under test is compared to this standard. When

defects are found, they should be identified and located by introducing

faults into the artificial line. This is more difficult than with the

method referenced in paragraph (f)(5)(i) of this section since this

measurement is more sensitive to minor faults and only a single trace

is used.

(iii) Open circuit structural return loss using level tracer. The

step-by-step measurement procedure using the level tracer for loaded

loops shall be as shown in Figure 10. The cable pair is compared to a

PBN.

(6) Test equipment. Equipment for performing these tests is shown

in Figures 8 through 10. For loaded loops, artificial loaded lines must

be of the same gauge and loading scheme as the line under test. For

nonloaded loops, artificial nonloaded lines must be of the same gauge

as the line under test. Artificial lines should be arranged using

switches or other quick connect arrangements to speed testing and

troubleshooting. Figures 8 through 10 are as follows:

BILLING CODE 3410-15-P

[[Page 23979]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.030

[[Page 23980]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.031

[[Page 23981]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.032

BILLING CODE 3410-15-C

[[Page 23982]]

(7) Applicable results. (i) For loaded and nonloaded loops, the two

traces in the pulse return pattern or impedance method (paragraph

(f)(5)(i) of this section) shall be essentially identical. The degree

of comparison required of the two traces is to be determined by

experience.

(ii) For loaded loops, results for return loss measurements using a

level tracer, with artificial line, in lieu of a PBN (paragraph

(f)(5)(ii) of this section) shall meet the following requirements:

(A) For D66 and H88 loaded cables the structural return loss (SRL)

values shall range between 28 and 39 dB, respectively, at the critical

frequency of structural return loss (CFSRL) within the pass band of the

loading system being used. The minimum SRL value for uniform gauge

shall be 25 dB CFSRL. These SRL values apply for loaded cables of

uniform gauge for the entire length of the subscriber loop circuit.

Subscriber loop circuits shall meet the loading spacing deviations and

the cable mutual capacitance requirements in the applicable RUS cable

specifications;

(B) For mixed gauge loaded cables the SRL values shall be 25 and 27

dB CFSRL, respectively, and the minimum SRL value shall be 22 dB CFSRL;

and

(C) The two traces in the pulse return pattern should be

essentially identical. The degree of comparison required of the two

traces is determined by experience.

(iii) For loaded loops, the results of open circuit structural

return loss measurements using a level tracer (paragraph (f)(5)(iii) of

this section) shall meet the following requirements. For D66 and H88

loaded cables with uniform or mixed gauges, the worst value allowed for

measured open circuit structural return loss between 1,000-3,500 Hz and

1,000-3,000 Hz, respectively, shall be approximately 0.9 dB (round

trip) for each 100 ohms outside plant dc loop resistance including the

resistance of the load coils. The value of 0.9 dB per 100 ohms for the

round trip loss remains reasonably accurate as long as:

(A) The subscriber end section of the loaded pair under test is

approximately 2,250 ft (685 m) for D66 loading or 3,000 ft (914 m) for

H88 loading in length; and

(B) The one-way 1,000 Hz loss does not exceed 10 dB.

(iv) For loaded loops, the measured value of open circuit

structural return loss can only be as accurate as the degree to which

the dc loop resistance of the loaded pair under test is known. Most

accurate results shall be obtained when the dc loop resistance is known

by actual measurements as described in paragraph (d) of this section.

Furthermore, where the dc loop resistance is measured at the same time

as the open circuit structural return loss, no correction for

temperature is needed because the loss is directly proportional to the

loop resistance. Where it is not practical to measure the dc loop

resistance, it shall be calculated and corrected for temperature as

specified in paragraph (d)(6)(ii) of this section. When measuring

existing plant, care shall be taken to verify the accuracy of the

records, if they are used for the calculation of the dc loop

resistance. For buried plant, the temperature correction shall be based

at the normal depth of the cable in the ground. (Temperature can be

measured by boring a hole to cable depth with a ground rod, placing a

thermometer in the ground at the cable depth, and taking and averaging

several readings during the course of the resistance measurements.) For

aerial cable it shall be based on the temperature inside the cable

sheath.

(v) For loaded loops, the best correlation between the measured and

the expected results shall be obtained when the cable is of one gauge,

one size, and the far end section is approximately 2,250 ft (685 m) for

D66 loading or 3,000 ft (914 m) for H88 loading. Mixing gauges and

cable sizes will result in undesirable small reflections whose

frequency characteristics and magnitude cannot be accurately predicted.

In subscriber loop applications, cable gauge may be somewhat uniform

but the cable pair size most likely will not be uniform as cable pair

sizes taper off toward the customer access location and a downward

adjustment of 1 dB of the allowed value shall be acceptable. ``Long''

end sections (as defined in TE&CM Section 424, ``Guideline for

Telecommunications Subscriber Loop Plant'') lower the expected value, a

further downward adjustment of 3 dB in the allowed value shall be

acceptable.

[[Page 23983]]

(vi) For loaded loops, the limiting factor when making open circuit

structural return loss measurements is when the 1,000 Hz one-way loss

of the loaded cable pair under test becomes 10 dB or greater; it

becomes difficult to detect the presence of irregularities beyond the

10 dB point on the loop. To overcome this difficulty, loaded loops

having a one-way loss at 1,000 Hz greater than 10 dB shall be opened at

some convenient point (such as a pedestal or ready access enclosure)

and loss measurements at the individual portions measuring less than 10

dB one-way shall be made separately. When field mounted voice frequency

repeaters are used, the measurement shall be made at the repeater

location in both directions.

(8) Data record. (i) When performing a pulse return pattern or

impedance open circuit measurement on loaded and nonloaded loops, a

``check mark'' indicating that the pair tests good or an ``X''

indicating that the pair does not test good shall be recorded in the

SRL column. A suggested format similar to Format I for subscriber loops

in Sec. 1755.407 or a format specified in the applicable construction

contract may be used.

(ii) When performing open circuit return loss measurements using

the return loss balanced to an artificial line or return loss using a

level tracer on loaded loops, the value of the poorest (lowest

numerical value) SRL and its frequency in the proper column between

1,000 and 3,500 Hz for D66 loading or between 1,000 and 3,000 Hz for

H88 loading shall be recorded. A suggested format similar to Format I

for subscriber loops in Sec. 1755.407 or a format specified in the

applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the more common

causes for failing to obtain the desired results may be due to reversed

load coil windings, missing load coils, bridge taps between load coils,

load coil spacing irregularities, excessive end sections, cables having

high or low mutual capacitance, load coils inadvertently installed in

nonloaded loops, moisture or water in the cable, load coils having the

wrong inductance, split pairs, and improperly spliced connectors. The

above can occur singularly or in combination. Experience to date

indicates that the most common problems are missing load coils,

reversed load coil windings or bridge taps.

(g) Cable insertion loss measurement (carrier frequencies). (1)

When specified by the borrower, carrier frequency insertion loss

measurements shall be made on cable pairs used for T1, T1C, and/or

station carrier systems. Carrier frequency insertion loss shall be made

on a minimum of three pairs. Select at least one pair near the outside

of the core unit layup. If the three measured pairs are within 10% of

the calculated loss in dB corrected for temperature, no further testing

is necessary. If any of the measured pairs of a section are not within

10% of the calculated loss in dB, all pairs in that section used for

carrier transmission shall be measured.

(2) Method of measurement. The step-by-step method of measurement

shall be as shown in Figure 11.

(3) Test equipment. The test equipment is shown in Figure 11 as

follows:

BILLING CODE 3410-15-P

[[Page 23984]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.033

BILLING CODE 3410-15-C

[[Page 23985]]

(4) Applicable results. (i) The highest frequency to be measured is

determined by the type of carrier system. For T1 type carrier, the

highest frequency is normally 772 kHz. For T1C type carrier, the

highest frequency is normally 1576 kHz. The highest frequency to be

measured for station carrier is 140 kHz.

(ii) The measured insertion loss of the cable shall be within

10% of the calculated loss in dB when the loss is corrected

for temperature.

(iii) The calculated insertion loss is computed as follows:

(A) Multiply the length of each different gauge by the applicable

dB per unit length as shown in Table 7 or 8 as follows:

Table 7.--Cable Attenuation @ 68 deg.F (20 deg.C) Filled Cables--Solid Insulation

----------------------------------------------------------------------------------------------------------------

Frequency (kHz) Attenuation dB/mile (dB/km) Gauge (AWG)

----------------------------------------------------------------------------------------------------------------

19 22 24 26

----------------------------------------------------------------------------------------------------------------

10.......................................... 2.8 (1.7) 4.8 (2.9) 6.4 (3.9) 8.5 (5.3)

20.......................................... 3.2 (2.0) 5.8 (3.6) 8.2 (5.1) 11.2 (6.9)

40.......................................... 3.6 (2.2) 6.5 (4.0) 9.6 (6.0) 13.9 (8.6)

60.......................................... 4.0 (2.5) 6.9 (4.2) 10.3 (6.4) 15.2 (9.4)

80.......................................... 4.5 (2.8) 7.3 (4.5) 10.7 (6.6) 16.0 (9.9)

100......................................... 4.9 (3.0) 7.7 (4.7) 11.1 (6.8) 16.5 (10.2)

112......................................... 5.2 (3.2) 8.0 (4.9) 11.3 (7.0) 16.8 (10.5)

120......................................... 5.4 (3.3) 8.1 (5.0) 11.5 (7.1) 17.0 (10.6)

140......................................... 5.8 (3.6) 8.6 (5.3) 11.9 (7.4) 17.4 (10.8)

160......................................... 6.2 (3.8) 9.0 (5.6) 12.3 (7.6) 17.8 (11.1)

180......................................... 6.6 (4.1) 9.5 (5.9) 12.7 (7.9) 18.2 (11.3)

200......................................... 7.0 (4.3) 10.0 (6.2) 13.2 (8.2) 18.6 (11.5)

300......................................... 8.7 (5.4) 12.2 (7.5) 15.4 (9.6) 20.6 (12.8)

400......................................... 10.0 (6.2) 14.1 (8.8) 17.7 (11.0) 22.9 (14.2)

500......................................... 11.2 (6.9) 15.9 (9.8) 19.8 (12.3) 25.2 (15.6)

600......................................... 12.2 (7.5) 17.5 (10.9) 21.8 (13.6) 27.4 (17.0)

700......................................... 13.2 (8.2) 19.0 (11.8) 23.6 (14.7) 29.6 (18.4)

772......................................... 13.8 (8.5) 19.9 (12.4) 24.8 (15.4) 31.4 (19.5)

800......................................... 14.2 (8.8) 20.1 (12.5) 27.4 (17.1) 31.7 (19.7)

900......................................... 14.8 (9.2) 21.6 (13.4) 29.0 (18.0) 33.8 (21.0)

1000........................................ 15.8 (9.8) 22.7 (14.1) 31.1 (19.3) 35.9 (22.3)

1100........................................ 16.4 (10.2) 23.8 (14.8) 32.7 (20.3) 38.0 (23.6)

1200........................................ 17.4 (10.8) 24.8 (15.4) 34.3 (21.3) 40.0 (24.9)

1300........................................ 17.9 (11.1) 25.9 (16.1) 35.4 (22.0) 41.7 (25.9)

1400........................................ 19.0 (11.8) 26.9 (16.7) 37.0 (23.0) 43.3 (26.9)

1500........................................ 19.5 (12.1) 28.0 (17.4) 38.0 (23.6) 44.3 (27.6)

1576........................................ 20.1 (12.4) 29.0 (18.0) 39.0 (24.3) 44.4 (28.2)

----------------------------------------------------------------------------------------------------------------

Table 8.--Cable Attenuation @ 68 deg.F (20 deg.C) Filled Cables--Expanded Insulation

----------------------------------------------------------------------------------------------------------------

Attenuation dB/mile (dB/km) Gauge (AWG)

Frequency (kHz) -------------------------------------------------------------------

19 22 24 26

----------------------------------------------------------------------------------------------------------------

10.......................................... 3.0 (1.8) 4.9 (3.0) 6.5 (4.0) 8.6 (5.3)

20.......................................... 3.5 (2.1) 6.0 (4.1) 8.5 (5.2) 11.5 (7.1)

40.......................................... 4.0 (2.5) 7.0 (4.3) 10.2 (6.3) 14.4 (8.9)

60.......................................... 4.5 (2.8) 7.5 (4.6) 11.1 (6.8) 16.0 (9.9)

80.......................................... 5.2 (3.3) 7.9 (4.9) 11.3 (6.9) 16.2 (10.1)

100......................................... 5.8 (3.6) 8.4 (5.2) 11.6 (7.2) 16.4 (10.2)

112......................................... 6.0 (3.8) 8.8 (5.4) 11.9 (7.4) 16.6 (10.3)

120......................................... 6.2 (3.9) 9.0 (5.6) 12.1 (7.5) 16.9 (10.5)

140......................................... 6.6 (4.1) 9.5 (5.9) 12.7 (7.9) 17.2 (10.7)

160......................................... 6.9 (4.3) 10.0 (6.2) 13.2 (8.2) 17.4 (10.8)

180......................................... 7.4 (4.6) 10.6 (6.6) 13.7 (8.5) 17.9 (11.1)

200......................................... 7.9 (4.9) 11.1 (6.9) 14.2 (8.8) 18.5 (11.5)

300......................................... 9.5 (5.9) 13.2 (8.2) 16.8 (10.5) 21.6 (13.4)

400......................................... 11.1 (6.9) 15.3 (9.5) 19.5 (12.1) 24.3 (15.1)

500......................................... 12.1 (7.5) 17.9 (11.1) 22.2 (13.8) 27.4 (17.1)

600......................................... 13.7 (8.5) 19.5 (12.1) 24.3 (15.1) 29.6 (18.4)

700......................................... 14.8 (9.2) 21.1 (13.1) 26.4 (16.4) 32.2 (20.0)

772......................................... 15.3 (9.5) 21.6 (13.4) 27.4 (17.1) 33.8 (21.90)

800......................................... 15.8 (9.8) 22.2 (13.8) 28.0 (17.4) 34.4 (21.3)

900......................................... 17.0 (10.5) 23.8 (14.8) 29.6 (18.4) 36.4 (22.6)

1000........................................ 17.4 (10.8) 24.8 (15.4) 31.1 (19.3) 38.5 (23.9)

1100........................................ 17.9 (11.1) 26.4 (16.4) 33.3 (20.7) 40.6 (25.3)

1200........................................ 19.0 (11.8) 27.4 (17.1 34.3 (21.3) 42.2 (26.2)

1300........................................ 19.5 (12.1) 28.5 (17.7) 35.9 (22.3) 43.8 (27.2)

1400........................................ 20.1 (12.5 29.6 (18.4) 37.0 (23.0) 45.9 (28.5)

1500........................................ 20.6 (12.8) 30.6 (19.0) 38.5 (23.9) 47.5 (29.5)

1576........................................ 21.6 (13.4) 31.1 (19.3) 39.1 (24.3) 48.6 (30.2)

----------------------------------------------------------------------------------------------------------------

[[Page 23986]]

(B) Add the individual losses for each gauge to give the total

calculated insertion loss at a temperature of 68 deg.F (20 deg.C);

(C) Correct the total calculated insertion loss at the temperature

of 68 deg.F (20 deg.C) to the measurement temperature by the following

formulae:

At = A68 x [1 + 0.0012 x (t -- 68)] for

English Units

At = A20 x [1 + 0.0022 x (t--20)] for Metric

Units

Where:

At = Insertion loss at the measurement temperature in

dB.

A68 = Insertion loss at a temperature of 68 deg.F in dB.

A20 = Insertion loss at a temperature of 20 deg.C in dB.

t = Measurement temperature in deg.F or ( deg.C); and

(D) Compare the calculated insertion loss at the measurement

temperature to the measured insertion loss to determine compliance with

the requirement specified in paragraph (g)(4)(ii) of this section.

(Note: Attenuation varies directly with temperature. For each

10 deg.F (5.6 deg.C) change in temperature increase or

decrease the attenuation by 1%.)

(iv) If the measured value exceeds the 10% allowable

variation, the cause shall be determined and corrective action shall be

taken to remedy the problem.

(5) Data record. Results of carrier frequency insertion loss

measurements for station, T1, and/or T1C type carrier shall be

recorded. Suggested formats similar to Format III, Outside Plant

Acceptance Tests--T1 or T1C Carrier Pairs, and Format IV, Outside Plant

Acceptance Tests--Station Carrier Pairs, in Sec. 1755.407 or formats

specified in the applicable construction contract may be used.

(6) Probable causes for nonconformance. If the measured loss is

low, the cable records are likely to be in error. If the measured loss

is high, there may be bridge taps, load coils or voice frequency build-

out capacitors connected to the cable pairs or the cable records may be

in error. Figures 12 and 13 are examples that show the effects of

bridge taps and load coils in the carrier path. Figures 12 and 13 are

as follows:

BILLING CODE 3410-15-P

[[Page 23987]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.034

[[Page 23988]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.035

BILLING CODE 3410-15-C

[[Page 23989]]

Sec. 1755.404 Fiber optic cable telecommunications plant measurements.

(a) Armor continuity. (1) Tests and measurements shall be made to

ensure that the armor of fiber optic cables is continuous. There are

two areas of concern. The first is armor bonding within a splice and

the second is armor continuity between splices.

(2) Measurement techniques outlined here for verification of armor

continuity are applicable to buried fiber optic cable plant.

Measurements of armor continuity between splices in aerial, armored,

fiber optic cable should be made prior to completion of splicing.

Conclusive results cannot be obtained on aerial plant after all bonds

have been completed to the supporting strand, multigrounded neutral,

etc.

(3) Method of measurement. Armor continuity within splices shall be

measured with a cable shield splice continuity test set. The step-by-

step measurement procedure outlined in the manufacturer's operating

instructions for the specific test equipment being used shall be

followed.

(4) Test equipment. A cable shield splice continuity tester shall

be used to measure armor continuity within splices.

(5) Applicable results. When utilizing shield continuity testers to

measure armor continuity within splices, refer to the manufacturer's

published information covering the specific test equipment to be used

and for anticipated results.

(6) Data record. Measurement data from armor continuity tests shall

be recorded together with anticipated values in an appropriate format

to permit comparison. The recorded data shall include specific

location, cable size, and cable type, if known, etc.

(7) Probable causes for nonconformance. Among probable causes for

nonconformance are broken or damaged armors, bad bonding harnesses,

poorly connected bonding clamps, loose bonding lugs, etc.

(b) Fiber optic splice loss measurement. (1) After placement of all

fiber optic cable plant has been completed and spliced together to form

a continuous optical link between end termination points, splice loss

measurements shall be performed on all field and central office splice

points.

(2) Method of measurement. (i) Field splice loss measurements shall

be made between the end termination points at 1310 and/or 1550

nanometers for single mode fibers and in accordance with Figure 14. Two

splice loss measurements shall be made between the end termination

points. The first measurement shall be from termination point A to

termination point B. The second measurement shall be from termination

point B to termination point A.

(ii) CO splice loss measurements shall be made at 1310 and/or 1550

nanometers for single mode fibers and in accordance with Figure 15. Two

splice loss measurements shall be made between the end termination

points. The first measurement shall be from termination point A to

termination point B. The second measurement shall be from termination

point B to termination point A.

(3) Test equipment. The test equipment is shown in Figures 14 and

15. The optical time domain reflectometer (OTDR) used for the testing

should have dual wave length capability. Figures 14 and 15 are as

follows:

BILLING CODE 3410-15-P

[[Page 23990]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.036

[[Page 23991]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.037

BILLING CODE 3410-15-C

[[Page 23992]]

(4) Applicable results. (i) The splice loss for each single mode

field splice shall be the bi-directional average of the two OTDR

readings. To calculate the actual splice loss, substitute the OTDR

readings maintaining the sign of the loss (+) or apparent gain (-) into

the following equation:

[GRAPHIC] [TIFF OMITTED] TR02MY97.021

(ii) When specified in the applicable construction contract, the

splice loss of each field splice at 1310 and/or 1550 nanometers shall

not exceed the limit specified in the contract.

(iii) When no limit is specified in the applicable construction

contract, the splice loss of each field splice shall not exceed 0.2 dB

at 1310 and/or 1550 nanometers.

(iv) The splice loss for each single mode CO splice shall be the

bi-directional average of the two OTDR reading. To calculate actual

splice loss, substitute the OTDR reading, maintaining the sign of the

loss (+) or apparent gain (-), into the equation specified in paragraph

(b)(4)(i) of this section.

(v) When specified in the applicable construction contract, the

splice loss of each central office splice at 1310 and/or 1550

nanometers shall not exceed the limit specified in the contract.

(vi) When no limit is specified in the applicable construction

contract, the splice loss of each central office splice shall not

exceed 1.2 dB at 1310 and/or 1550 nanometers.

(5) Data record. The measurement data shall be recorded. A

suggested format similar to Format V, Outside Plant Acceptance Test--

Fiber Optic Telecommunications Plant, in Sec. 1755.407 or a format

specified in the applicable construction contract may be used.

(6) Probable causes for nonconformance. When the results of the

splice loss measurements exceed the specified limits the following

factors should be checked:

(i) Proper end preparation of the fibers;

(ii) End separation between the fiber ends;

(iii) Lateral misalignment of fiber cores;

(iv) Angular misalignment of fiber cores;

(v) Fresnel reflection;

(vi) Contamination between fiber ends;

(vii) Core deformation; or

(viii) Mode-field diameter mismatch.

(c) End-to-end attenuation measurement. (1) After placement of all

fiber optic cable plant has been completed and spliced together to form

a continuous optical link between end termination points, end-to-end

attenuation measurements shall be performed on each optical fiber

within the cable.

(2) Method of measurement. For single mode fibers, the end-to-end

attenuation measurements of each optical fiber at 1310 and/or 1550

nanometers in each direction between end termination points shall be

performed in accordance with Figure 16.

(3) Test equipment. The test equipment is shown in Figure 16 as

follows:

BILLING CODE 3410-15-P

[[Page 23993]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.038

BILLING CODE 3410-15-C

[[Page 23994]]

(4) Applicable results. The end-to-end attenuation of each single

mode optical fiber at 1310 and/or 1550 nanometers shall not exceed the

limits specified in the applicable construction contract.

(5) Data record. The measurement data shall be recorded. A

suggested format similar to Format V for fiber optic telecommunications

plant in Sec. 1755.407 or on a format specified in the applicable

construction contract may be used.

(6) Probable causes for nonconformance. Failure of each optical

fiber to meet the end-to-end attenuation limit could be attributed to

the following:

(i) Excessive field or central office splice loss;

(ii) Excessive cable attenuation; or

(iii) Damage to the fiber optic cable during installation.

(d) End-to-end fiber signature measurement. (1) After placement of

all fiber optic cable plant has been completed and spliced together to

form a continuous optical link between end termination points, end-to-

end fiber signature testing shall be performed on each optical fiber

within the cable.

(2) Method of measurement. For single mode fibers, the end-to-end

fiber signature measurement of each optical fiber in each direction

shall be performed between end termination points at 1310 and/or 1550

nanometers in accordance with Figure 17.

(3) Test equipment. The test equipment is shown in Figure 17 as

follows:

BILLING CODE 3410-15-P

[[Page 23995]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.039

BILLING CODE 3410-15-C

[[Page 23996]]

(4) Applicable results. The appearance of each optical fiber

between end termination points.

(5) Data record. Plot the trace of each optical fiber and retain as

a permanent record for future comparison if needed.

(6) Probable causes for nonconformance. None.

Sec. 1755.405 Voiceband data transmission measurements.

(a) The data transmission measurements listed in this section shall

be used to determine the acceptability of trunk and nonloaded

subscriber loop circuits for data modem transmission.

(b) Signal-to-C notched noise (S/CNN) measurement. (1) When

specified by the borrower, S/CNN measurements shall be made on trunk

circuits and nonloaded subscriber loops. For trunk circuits, the

measurement shall be made between CO locations. For nonloaded

subscriber loops, the measurement shall be made from the CO to the

station protector of the NID at the customer's access location.

(2) S/CNN is the logarithmic ratio expressed in dB of a 1,004 Hz

holding tone signal compared to the C-message weighted noise level. S/

CNN is one of the most important transmission parameters affecting the

performance of data transmission because proper modem operation

requires low noise relative to received power level. Since modulated

carriers are used in data communication systems, noise measurements

need to be performed with power on the connection to activate equipment

having signal-level-dependent noise sources. For 4 kHz channels, a

1,004 Hz holding tone is used to activate the signal-dependent

equipment on the channel or connection.

(3) Method of measurement. The S/CNN measurement shall be made

using a 1,004 Hz holding tone at -13 dBm0 (decibels relative to one

milliwatt, referred to a zero transmission level point) and performed

in accordance with American National Standards Institute (ANSI) T1.506-

1990, American National Standard for Telecommunications--Network

Performance--Transmission Specifications for Switched Exchange Access

Network including supplement ANSI T1.506a-1992, and American National

Standards Institute/Institute of Electrical and Electronics Engineers

(ANSI/IEEE) 743-1984, IEEE Standard Methods and Equipment for Measuring

the Transmission Characteristics of Analog Voice Frequency Circuits.

The ANSI T1.506-1990, American National Standard for

Telecommunications--Network Performance--Transmission Specifications

for Switched Exchange Access Network is incorporated by reference in

accordance with 5 U.S.C. 522(a) and 1 CFR part 51. Copies of ANSI

T1.506-1990 are available for inspection during normal business hours

at RUS, room 2845, U.S. Department of Agriculture, STOP 1598,

Washington, DC 20250-1598 or at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700, Washington, DC. Copies are

available from ANSI, Customer Service, 11 West 42nd Street, New York,

New York 10036, telephone number (212) 642-4900. The ANSI/IEEE 743-

1984, IEEE Standard Methods and Equipment for Measuring the

Transmission Characteristics of Analog Voice Frequency Circuits is

incorporated by reference in accordance with 5 U.S.C. 522(a) and 1 CFR

part 51. Copies of ANSI/IEEE 743-1984 are available for inspection

during normal business hours at RUS, room 2845, U.S. Department of

Agriculture, STOP 1598, Washington, DC 20250-1598 or at the Office of

the Federal Register, 800 North Capitol Street, NW., suite 700,

Washington, DC. Copies are available from ANSI, Customer Service, 11

West 42nd Street, New York, New York 10036, telephone number (212) 642-

4900.

(4) Test equipment. The equipment for performing the measurement

shall be in accordance with ANSI/IEEE 743-1984.

(5) Applicable results. The S/CNN for both trunk and nonloaded

subscriber loop circuits shall not be less than 31 dB.

(6) Data record. The measurement data shall be recorded. Suggested

formats similar to Format VI, Voiceband Data Transmission Tests--

Nonloaded Subscriber Loops, and Format VII, Voiceband Data Transmission

Tests--Trunk Circuits, in Sec. 1755.407 or formats specified in the

applicable construction contract may be used.

(7) Probable causes for nonconformance. Some of the causes for

failing to obtain the desired results may be due to excessive harmonic

distortion, quantizing noise, phase and amplitude jitter, and loss in

digital pads used for level settings.

(c) Signal-to-intermodulation distortion (S/IMD) measurement. (1)

When specified by the borrower, S/IMD measurements shall be made on

trunk circuits and nonloaded subscriber loops. For trunk circuits, the

measurement shall be made between CO locations. For nonloaded

subscriber loops, the measurement shall be made from the CO to the

station protector of the NID at the customer's access location.

(2) S/IMD is a measure of the distortion produced by extraneous

frequency cross products, known as intermodulation products, when a

multi-tone tone signal is applied to a system.

(3) Intermodulation distortion (IMD) is caused by system

nonlinearities acting upon the harmonic frequencies produced from an

input of multiple tones. The products resulting from IMD can be more

damaging than noise in terms of producing data transmission errors.

(4) IMD is measured as a signal to distortion ratio and is

expressed as the logarithmic ratio in dB of the composite power of four

resulting test frequencies to the total power of specific higher order

distortion products that are produced. The higher order products are

measured at both the 2nd order and 3rd order and are designated R2 and

R3, respectively. The four frequency testing for IMD is produced with

four tones of 857, 863, 1,372, and 1,388 Hz input at a composite power

level of -13 dBm0.

(5) Method of measurement. The S/IMD measurement shall be performed

in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(6) Test equipment. The equipment for performing the measurement

shall be in accordance with ANSI/IEEE 743-1984.

(7) Applicable results. The 2nd order (R2) S/IMD for both trunk and

nonloaded subscriber loop circuits shall not be less than 40 dB. The

3rd order (R3) S/IMD for both trunk and nonloaded subscriber loop

circuits shall not be less than 40 dB.

(8) Data record. The measurement data shall be recorded. Suggested

formats similar to Format VI for nonloaded subscriber loops and Format

VII for trunk circuits in Sec. 1755.407 or formats specified in the

applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the causes for

failing to obtain the desired results may be due to channel

nonlinearities, such as compression and clipping, which cause harmonic

and intermodulation distortion in a voiceband signal.

(d) Envelope delay distortion (EDD) measurement. (1) When specified

by the borrower, EDD measurements shall be made on trunk circuits and

nonloaded subscriber loops. For trunk circuits, the measurement shall

be made between CO locations. For nonloaded subscriber loops, the

measurement shall be made from the CO to the station protector of the

NID at the customer's access location.

[[Page 23997]]

(2) EDD is a measure of the linearity or uniformity of the phase

versus frequency characteristics of a transmission facility. EDD is

also known as relative envelope delay (RED).

(3) EDD is specifically defined as the delay relative to the

envelope delay at the reference frequency of 1,704 Hz. EDD is typically

measured at two frequencies, one low and one high in the voiceband. The

low frequency measurement is made at 604 Hz. The high frequency

measurement is made at 2,804 Hz.

(4) Method of measurement. The EDD measurement shall be performed

in accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(5) Test equipment. The equipment for performing the measurement

shall be in accordance with ANSI/IEEE 743-1984.

(6) Applicable results. The EDD for both trunk and nonloaded

subscriber loop circuits at the low frequency of 604 Hz shall not

exceed 1,500 microseconds. The EDD for both trunk and nonloaded

subscriber loop circuits at the high frequency of 2,804 Hz shall not

exceed 1,000 microseconds.

(7) Data record. The measurement data shall be recorded. Suggested

formats similar to Format VI for nonloaded subscriber loops and Format

VII for trunk circuits in Sec. 1755.407 or formats specified in the

applicable construction contract may be used.

(8) Probable causes for nonconformance. Some of the causes for

failing to obtain the desired results may be due to nonlinearity of the

phase versus frequency characteristic of the transmission facility.

This nonlinear phase versus frequency characteristic of the

transmission facility causes the various frequency components to travel

at different transit times which results in successively transmitted

data pulses to overlap at the receive end. The overlapping of the

pulses at the receive end results in distortion of the received signal.

Excessive EDD on the transmission facility may be reduced using data

modems with equalization or by conditioning the transmission line.

(e) Amplitude jitter (AJ) measurement. (1) When specified by the

borrower, AJ measurements shall be made on trunk circuits and nonloaded

subscriber loops. For trunk circuits, the measurement shall be made

between CO locations. For nonloaded subscriber loops, the measurement

shall be made from the CO to the station protector of the NID at the

customer's access location.

(2) AJ is any fluctuation in the peak amplitude value of a fixed

tone signal at 1,004 Hz from its nominal value. AJ is expressed in peak

percent amplitude modulation.

(3) AJ is measured in two separate frequency bands, 4-300 Hz and

20--300 Hz. The 4--300 Hz band is important for modems employing echo

canceling capabilities. The 20-300 Hz band is used for modems that do

not employ echo cancelers.

(4) Amplitude modulation can affect the error performance of

voiceband data modems. The measurement of amplitude jitter indicates

the total effect on the amplitude of the holding tone of incidental

amplitude modulation and other sources including quantizing and message

noise, impulse noise, gain hits, phase jitter, and additive tones such

as single-frequency interference.

(5) Method of measurement. The AJ measurement shall be performed in

accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(6) Test equipment. The equipment for performing the measurement

shall be in accordance with ANSI/IEEE 743-1984.

(7) Applicable results. The AJ for both trunk and nonloaded

subscriber loop circuits in the 4--300 Hz frequency band shall not

exceed 6%. The AJ for both trunk and nonloaded subscriber loop circuits

in the 20--300 Hz frequency band shall not exceed 5%.

(8) Data record. The measurement data shall be recorded. Suggested

formats similar to Format VI for nonloaded subscriber loops and Format

VII for trunk circuits in Sec. 1755.407 or formats specified in the

applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the causes for

failing to obtain the desired results may be due to excessive S/CNN,

impulse noise, and phase jitter.

(f) Phase jitter (PJ) measurement. (1) When specified by the

borrower, PJ measurements shall be made on trunk circuits and nonloaded

subscriber loops. For trunk circuits, the measurement shall be made

between CO locations. For nonloaded subscriber loops, the measurement

shall be made from the CO to the station protector of the NID at the

customer's access location.

(2) PJ is any fluctuation in the zero crossings of a fixed tone

signal (usually 1,004 Hz) from their nominal position in time within

the voiceband. PJ is expressed in terms of either degrees peak-to-peak

( deg.p-p) or in terms of a Unit Interval (UI). One UI is equal to

360 deg. p-p.

(3) PJ measurements are typically performed in two nominal

frequency bands. The frequency bands are 20-300 Hz band and either the

2-300 Hz band or the 4-300 Hz band. The 20-300 Hz band is important to

all phase-detecting modems. The 4-300 Hz band or the 2-300 Hz band is

important for modems employing echo canceling capabilities.

(4) Phase jitter can affect the error performance of voiceband data

modems that use phase detection techniques. The measurement of phase

jitter indicates the total effect on the holding tone of incidental

phase modulation and other sources including quantizing and message

noise, impulse noise, phase hits, additive tones such as single-

frequency interference, and digital timing jitter.

(5) Method of measurement. The PJ measurement shall be performed in

accordance with ANSI T1.506-1990 and ANSI/IEEE 743-1984.

(6) Test equipment. The equipment for performing the measurement

shall be in accordance with ANSI/IEEE 743-1984.

(7) Applicable results. The PJ for both trunk and nonloaded

subscriber loop circuits in the 4-300 Hz frequency band shall not

exceed 6.5 deg. p-p. The PJ for both trunk and nonloaded subscriber

loop circuits in the 20-300 Hz frequency band shall not exceed

10.0 deg. p-p.

(8) Data record. The measurement data shall be recorded. Suggested

formats similar to Format VI for nonloaded subscriber loops and Format

VII for trunk circuits in Sec. 1755.407 or formats specified in the

applicable construction contract may be used.

(9) Probable causes for nonconformance. Some of the causes for

failing to obtain the desired results may be due to excessive S/CNN,

impulse noise, and amplitude jitter.

(g) Impulse noise measurement. (1) When specified by the borrower,

impulse noise measurements shall be made on trunk circuits and

nonloaded subscriber loops. For trunk circuits, the measurement shall

be made between CO locations. For nonloaded subscriber loops, the

measurement shall be made from the CO to the station protector of the

NID at the customer's access location.

(2) Impulse noise is a measure of the presence of unusually large

noise excursions of short duration that are beyond the normal

background noise levels on a facility. Impulse noise is typically

measured by counting the number of occurrences beyond a particular

noise reference threshold in a given time interval. The noise reference

level is C-message weighted.

(3) Method of measurement. The impulse noise measurement shall be

performed using a 1,004 Hz tone at -13 dBm0 and in accordance with ANSI

T1.506-1990 and ANSI/IEEE 743-1984.

[[Page 23998]]

(4) Test equipment. The equipment for performing the measurement

shall be in accordance with ANSI/IEEE 743-1984.

(5) Applicable results. The impulse noise for both trunk and

nonloaded subscriber loop circuits shall not exceed 65 dBrnC0 (decibels

relative to one picowatt reference noise level, measured with C-message

frequency weighting, referred to a zero transmission level point). The

impulse noise requirement shall be based upon a maximum of 5 counts in

a 5 minute period at equal to or greater than the indicated noise

thresholds.

(6) Data record. The measurement data shall be recorded. Suggested

formats similar to Format VI for nonloaded subscriber loops and Format

VII for trunk circuits in Sec. 1755.407 or formats specified in the

applicable construction contract may be used.

(7) Probable causes for nonconformance. Some of the causes for

failing to obtain the desired results may be due to excessive transient

signals originating from the various switching operations.

Sec. 1755.406 Shield or armor ground resistance measurements.

(a) Shield or armor ground resistance measurements shall be made on

completed lengths of copper cable and wire plant and fiber optic cable

plant.

(b) Method of measurement. (1) The shield or armor ground

resistance measurement shall be made between the copper cable and wire

shield and ground and between the fiber optic cable armor and ground,

respectively. The measurement shall be made either on cable and wire

lengths before splicing and before any ground connections are made to

the cable or wire shields or armors. Optionally, the measurement may be

made on cable and wire lengths after splicing, but all ground

connections must be removed from the section under test.

(2) The method of measurement using either an insulation resistance

test set or a dc bridge type megohmmeter shall be as shown in Figure 18

as follows:

BILLING CODE 3410-15-P

[[Page 23999]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.040

BILLING CODE 3410-15-C

[[Page 24000]]

(c) Test equipment. (1) The shield or armor ground resistance

measurements may be made using an insulation resistance test set, a dc

bridge type megohmmeter, or a commercially available fault locator.

(2) The insulation resistance test set should have an output

voltage not to exceed 500 volts dc and may be hand cranked or battery

operated.

(3) The dc bridge type megohmmeter, which may be ac powered, should

have scales and multipliers which make it possible to accurately read

resistance values of 50,000 ohms to 10 megohms. The voltage that is

applied to the shield or armor during the test should not be less than

``250 volts dc'' nor greater than ``1,000 volts dc'' when using an

instrument having adjustable test voltage levels.

(4) Commercially available fault locators may be used in lieu of

the above equipment, if the devices are capable of detecting faults

having resistance values of 50,000 ohms to 10 megohms. Operation of the

devices and method of locating the faults should be in accordance with

manufacturer's instructions.

(d) Applicable results. (1) For all new copper cable and wire

facilities and all new fiber optic cable facilities, the shield or

armor ground resistance levels normally exceed 1 megohm-mile (1.6

megohm-km) at 68 deg.F (20 deg.C). A value of 100,000 ohm-mile (161,000

ohm-km) at 68 deg.F (20 deg.C) shall be the minimum acceptable value of

the shield or armor ground resistance.

(2) Shield or armor ground resistance varies inversely with length

and temperature. In addition other factors which may affect readings

could be soil conditions, faulty test equipment and incorrect test

procedures.

(3) For the resistance test method and dc bridge type megohmmeter,

the ohm-mile (ohm-km) value for the shield or armor ground resistance

shall be computed by multiplying the actual scale reading in ohms on

the test set by the length in miles (km) of the cable or wire under

test.

(4)(i) The objective shield or armor ground resistance may be

determined by dividing 100,000 by the length in miles (161,000 by the

length in km) of the cable or wire under test. The resulting value is

the minimum acceptable meter scale reading in ohms. Examples for

paragraphs (d)(3) and (d)(4) of this section are as follows:

Equation 1. Test Set: Scale Reading * Length = Resistance-Length

75,000 ohms * 3 miles = 225,000 ohm-mile

(75,000 ohms * 4.9 km = 367,000 ohm-km)

Equation 2. 100,000 ohm-mile ' Length = Minimum Acceptable

Meter Scale Reading

100,000 ohm-mile ' 3 miles = 33,333 ohms

(161,000 ohm-km ' 4.9 km = 32,857 ohms)

(ii) Since the 33,333 ohms (32,857 ohms) is the minimum acceptable

meter scale reading and the meter scale reading was 75,000 ohms, the

cable is considered to have met the 100,000 ohm-mile (161,000 ohm-km)

requirement.

(5) Due to the differences between various jacketing materials used

in manufacturing cable or wire and to varying soil conditions, it is

impractical to provide simple factors to predict the magnitude of

variation in shield or armor to ground resistance due to temperature.

The variations can, however, be substantial for wide excursions in

temperature from the ambient temperature of 68 deg.F (20 deg.C).

(e) Data record. The data shall be corrected to the length

requirement of ohm-mile (ohm-km) and a temperature of 68 deg.F

(20 deg.C) and shall be recorded on a form specified in the applicable

construction contract.

(f) Probable causes for nonconformance. (1) When results of

resistance measurements are below the 100,000 ohm-mile (161,000 ohm-km)

requirement at 68 deg.F (20 deg.C), the jacket temperature, soil

conditions, test equipment and method shall be reviewed before the

cable or wire is considered a failure. If the temperature is

approximately 68 deg.F (20 deg.C) and soil conditions are acceptable,

and a reading of less than 100,000 ohm-mile (161,000 ohm-km) is

indicated, check the calibration of the equipment; as well as, the test

method. If the equipment was found to be out of calibration,

recalibrate the equipment and remeasure the cable or wire. If the

temperature was 86 deg.F (30 deg.C) or higher, the cable or wire shall

be remeasured at a time when the temperature is approximately 68 deg.F

(20 deg.C). If the test was performed in unusually wet soil, the cable

or wire shall be retested after the soil has reached normal conditions.

If after completion of the above steps, the resistance value of 100,000

ohm-mile (161,000 ohm-km) or greater is obtained, the cable or wire

shall be considered acceptable.

(2) When the resistance value of the cable or wire is still found

to be below 100,000 ohm-mile (161,000 ohm-km) requirement after

completion of the steps listed in paragraph (f)(1) of this section, the

fault shall be isolated by performing shield or armor ground resistance

measurements on individual cable or wire sections.

(3) Once the fault or faults have been isolated, the cable or wire

jacket shall be repaired in accordance with Sec. 1755.200, RUS Standard

for Splicing Copper and Fiber Optic Cables or the entire cable or wire

section may be replaced at the request of the borrower.

Sec. 1755.407 Data formats.

The following suggested formats listed in this section may be used

for recording the test data:

BILLING CODE 3410-15-P

[[Page 24001]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.041

[[Page 24002]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.042

[[Page 24003]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.043

[[Page 24004]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.044

[[Page 24005]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.045

[[Page 24006]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.046

[[Page 24007]]

[GRAPHIC] [TIFF OMITTED] TR02MY97.047

[[Page 24008]]

Dated: April 24, 1997.

Jill Long Thompson,

Under Secretary, Rural Development.

[FR Doc. 97-11316 Filed 5-1-97; 8:45 am]

BILLING CODE 3410-15-C