A-8
Cisco 7401ASR Installation and Configuration Guide
OL-5419-01 B0
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-9
lists the RJ-45
console port signals.
Table A-10
lists the RJ-45 auxiliary 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-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
RING
1
1.
RING is not supported on Cisco-supplied adapters. To use this pin, you must create a customized
cable.
In
Ring Indication
5
GND
—
Signal Ground
6
RXD
In
Receive Data
7
2
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.
DSR/DCD
(RLSD)
In
Data Set Ready / Data Carrier Detect
(Receive Line Signal Detect)
8
CTS
In
Clear To Send (tracks RTS)
