Cisco Systems 7401ASR manual Console and Auxiliary Port Signals and Pinouts

Appendix A Specifications

Console and Auxiliary Port Signals and Pinouts

To determine whether a UTP cable is a crossover cable or a straight-through cable, hold the two RJ-45 connectors next to each other so you can see the colored wires inside the ends.

Examine the sequence of colored wires to determine the type of cable, as follows:

•Straight-through—The colored wires are in the same sequence at both ends of the cable.

•Crossover—The first (far left) colored wire at one end of the cable is the third colored wire at the other end of the cable.

Console and Auxiliary Port Signals and Pinouts

The Cisco 7401ASR router does not support Data Carrier Detect (DCD). Table A-9lists the RJ-45 console port signals.

Table A-9 Console Port Signals

Pin	Signal	Direction	Description
1	CTS	Out	Clear To Send (tracks RTS)
2	DSR	Out	Data Set Ready (always on)
3	RXD	Out	Receive Data
4	GND	—	Signal Ground
	—	—	Not connected
6	TXD	In	Transmit Data
7	DTR	In	Data Terminal Ready
8	RTS	In	Ready To Send

Table A-10lists the RJ-45 auxiliary port signals.

Table A-10 Auxiliary Port Signals

Pin	Signal	Direction	Description
1	RTS	Out	Ready To Send
2	DTR	Out	Data Terminal Ready
3	TXD	Out	Transmit Data
4	RING1	In	Ring Indication
5	GND	—	Signal Ground
6	RXD	In	Receive Data
72	DSR/DCD	In	Data Set Ready / Data Carrier Detect
	(RLSD)		(Receive Line Signal Detect)
8	CTS	In	Clear To Send (tracks RTS)

1.RING is not supported on Cisco-supplied adapters. To use this pin, you must create a customized cable.

2.Pin 7 can be used as a DCD input for connection to a modem. The RJ-45-to-DB-25F adapter maps DCD to this pin when used with a straight-through cable.

	Cisco 7401ASR Installation and Configuration Guide
A-8	OL-5419-01 B0