3com 5500-EI Quick Setup Guide

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A
PPENDIX
 B: P
IN
-
OUTS
Modem Cable
RJ-45 to RS-232 25-pin
Ethernet Port RJ-45 
Pin Assignments
10/100 and 1000BASE-T RJ-45 connections.
Table 10   Pin assignments
Screen
TxD
RxD
RTS
CTS
DSR
Ground
DCD
DTR
Screen
TxD
RxD
RTS
CTS
DSR
Ground
DCD
DTR
Shell
3
2
7
8
6
5
1
4
1
2
3
4
5
6
7
8
20
Switch 5500
Cable connector: RJ-45 female
RS-232 Modem Port
Cable connector: 25-pin male
Pin Number
10/100
1000
Ports configured as MDI
1
Transmit Data + 
Bidirectional Data A+
2
Transmit Data –
Bidirectional Data A-
3
Receive Data +
Bidirectional Data B+
4
Not assigned
Bidirectional Data C+
5
Not assigned
Bidirectional Data C-
6
Receive Data –
Bidirectional Data B-
7
Not assigned
Bidirectional Data D+
8
Not assigned
Bidirectional Data D-