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X.21 Cable Specifications

X.21 Cable
Pin Number
Description
Direction
Female DB15
Male DB15
 
From/To SGP
2
2
Transmit Data A-wire
From
3
3
RTS, Request to Send A-wire
From
4
4
Receive Data A-wire
To
5
5
DCD, Data Carrier Detect A-wire
To
6
6
Clock A-wire
To/From
8
8
GND, Common Signal Ground
N/A
9
9
Transmit Data B-wire
From
10
10
RTS, Request to Send B-wire
From
11
11
Receive Data B-wire
To
12
12
DCD, Data Carrier Detect B-wire
To
13
13
Clock B-wire
To/From

Rx
=Receive, Tx=Transmit, CTS=Clear to Send, RTS=Ready to Send,
DTR=Data Terminal Ready, DSR=Data Set Ready, DCD=Data Carrier Detect