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6620-3201
20 Serial port connectors
20.1 RS232 Serial Port Connectors
Depending upon the model, the asynchronous serial ports on may be presented as 25-way D sockets,
9-way D sockets or 8-pin RJ45 sockets. On some models, a combination of the above may be used.
The following table lists the pin designations for each type of connector:
25-way D
9-way D
RJ45
Description
RS232 signal
To DTE
To DCE
Pin #
Pin #
Pin #
Transmit data
TxD
Ä
2 3
6
Receive data
RxD
Ã
3 2
3
Ready to Send
RTS
Ä
4 7
1
Clear to Send
CTS
Ã
5 8
8
Data Set Ready
DSR
Ã
6 6
4
Ground GND
7
5
5
Data Carrier Detect
DCD
Ã
8 1
7
Transmitter Clock
TxC
Ä
15 n/a
n/a
Receiver Clock
RxC
Ã
17 n/a
n/a
Data Terminal Ready
DTR
Ä
20 4
2
External Transmitter
Clock
ETC
Ä
24 n/a
n/a
A range of suitable adapters and cables are available from Westermo.
20.2 X.21 Serial Port Connectors
On models
fi
tted with the X.21 synchronous serial option, the following pin-outs are used at the 25-
way D connector:
25-way D
Description
X.21 signal
Direction (with respect to router)
Pin #
Receive (A)
RxDA
out
2
Receive (B)
RxDB
out
3
Transmit (A)
TxDA
in
4
Transmit (B)
TxDB
in
5
Indication (B)
INDB
out
6
Ground GND
n/a
7
Control (B)
CTLB
in
8
Signal timing (B)
CLKB
in or out*
15
Signal timing (A)
CLKA
in or out*
17
Indication (B)
INDA
out
20
Control (A)
CTLA
in
22
There are two versions of the X.21 daughter card. One version is compatible with IR2140 and IR2420
routers, and one version is compatible with MW3520, MW3410 and VC5100 routers.
