B-14
SAMPLE INSTALLATION AND MAINTENANCE PROBLEMS
To fix these problems and establish compatibility across several products, new cable groups were
developed. These cable groups specify a standard set of pin assignments for four different connector
types. The connector and connection types are the:
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25-pair flat ribbon connector (manufactured by Amphenol Products)
15-pin D-type connector
Wire-lugs for screw terminal connections
8-pin modular jack
Table B-1, 50-Pin (25-Pair) Connector Configurations, shows the 25-pair connector pin assignments.
Table B-2, System 75 Versus System 85 Cable Comparisons, shows the various types of permitted
cables. TABLE B-1. 50-Pin (25-Pair) Connector Configurations
(INITIAL) SYSTEM 85 DS1 OR DMI
PINOUT FOR 50-PIN CONNECTOR
PIN NUMBERS FUNCTION
1 26 RECEIVE
45TRANSMIT
6 31 LOOPBACK
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.
.
OTHERS NOT USED
(PDS COMPATIBLE) SYSTEM 75/85
PINOUT FOR 50-PIN CONNECTOR
PIN NUMBERS FUNCTION
22 47 RECEIVE
23 48 TRANSMIT
24 49 LOOPBACK
OTHERS NOT USED