Installation guide

Cabling Specifications A-87
Channelized T1 Pinouts
Channelized T1 Pinouts
For the CT1, two standard T1 serial cables are available from Cisco Systems: null-modem
and straight-through. A straight-through cable connects your router to an external CSU.
Null-modem cables are used for back-to-back operation and testing.
The cables have male 15-pin DB connectors at each end to connect the CT1with the
external CSU.
The T1 interface cable has two 15-pin DB connectors at each end to connect the CT1with
the external T1 CSU. Figure A-21 shows the T1 interface cable, connectors and pinouts.
The T1 interface cables have two, male, 15-pin DB connectors (one at each end) to connect
the CT1 with the external CSU. Table A-36 lists the pinouts for the null-modem T1 cable
and Table A-37 lists the pinouts for the straight-through T1 cable.
Figure A-21 T1 Interface Cable
Table A-36 T1 Null-Modem Cable Pinouts
15-Pin DB Connector 15-Pin DB Connector
Signal Pin Pin Signal
Transmit Tip 1 3 Receive Tip
Receive Tip 3 1 Transmit Tip
Pin 1
Pin 9
Pin 11
Pin 3
Pin 1
Pin 9
Pin 11
Pin 3
72-XXXX-01 MIP
T1 or null-modem
connector (typical)
H2385