Router Auxiliary Aux Port

Auxiliary and Console Ports

The console and auxiliary ports on Cisco IOS® routers are asynchronous serial ports. The console port and the auxiliary port are configured as data terminal equipment (DTE). For Cisco 1000, 1600, 2500, 2600, and 3600 Series Routers, the console and auxiliary ports both use RJ-45 connectors. Adapters are available for connections to PC terminals, modems, or other external communications equipment.

This table shows the console port pinouts for the RJ-45 connector:

Console Port (DTE)
Pin¹	Signal	Input/Output
1	-	-
2	DTR	Output
3	TxD	Output
4	GND	-
5	GND	-
6	RxD	Input
7	DSR	Input
8	-	-

Any pin not referenced is not connected.

This table shows the auxiliary port pinouts of the RJ-45 connector:

Auxiliary Port (DTE)
Pin²	Signal	Input/Output
1	RTS	Output
2	DTR	Output
3	TXD	Output
4	GND	-
5	GND	-
6	RXD	Input
7	DSR	Input
8	CTS	Input

Any pin not referenced is not connected.

Identify a Rollover Cable

In order to identify a rollover cable, compare the two modular ends of the cable. Hold the cables in your hand, side-by-side, with the tab at the back. The wire connected to the pin on the outside of the left connector (pin 1) must be the same color as the pin on the outside of the right connector (pin 8). On Cisco cables, pin 1 is white on one connector, and pin 8 is white on the other connector.

This table shows the RJ-45 rolled (console) cable pinouts:

Signal	Pin	Pin	Signal
-	1	8	-
-	2	7	-
-	3	6	-
-	4	5	-
-	5	4	-
-	6	3	-
-	7	2	-
-	8	1	-