3com 3C16987A User Manual
42
A
PPENDIX
B: P
IN
-
OUTS
Modem Cable
9-pin to RS-232 25-pin
RJ45 Pin
Assignments
Assignments
Pin assignments are identical for 10BASE-T and 100BASE-TX RJ45
connectors
connectors
Screen
TxD
RxD
RTS
RTS
CTS
DSR
DSR
Ground
DCD
DTR
DTR
Screen
TxD
RxD
RTS
RTS
CTS
DSR
DSR
Ground
DCD
DTR
DTR
Shell
3
2
7
7
8
6
6
5
1
4
4
1
2
3
3
4
5
5
6
7
8
8
20
Switch 3300 SM
Cable connector: 9-pin female
Cable connector: 9-pin female
RS-232 Modem Port
Cable connector: 25-pin male
Cable connector: 25-pin male
Table 7 Pin assignments
Pin Number
Signal
Function
Ports configured as MDI
1
TxData +
Transmit data
2
TxData –
Transmit data
3
RxData +
Receive Data
4
Not assigned
5
Not assigned
6
RxData –
Receive data
7
Not assigned
8
Not assigned