Asynchronous Serial Connections - Cisco Catalyst 2000 Configuration Handbook

268 Cisco LAN Switching Configuration Handbook

Asynchronous Serial Connections

An asynchronous serial connection, such as the Aux port or a line on an access server,
requires an RJ-45 connection. For a back-to-back link between two async ports on two dif-
ferent routers, you must use a rollover cable. Rollover cables are usually flat eight-conductor
cables with RJ-45 connectors, fashioned so that pin 1 on one end goes to pin 8 on the other
end, pin 2 goes to pin 7, and so forth. Cisco normally supplies a rollover cable with a console
cable kit. Table A-4 shows the pinout connections for both ends of the rollover cable.
Table A-4 RJ-45 Connector Pinouts for Rollover Cables
RJ-45 Pin
End A
1
2
3
4
5
6
7
8
Description
End A
RTS
DTR
TxD
GND
GND
RxD
DSR
CTS
Description
End B
CTS
DSR
RxD
GND
GND
TxD
DTR
RTS
RJ-45 Pin
End B
8
7
6
5
4
3
2
1