3Com OfficeConnect User Manual page 15

Refer to Figure 5 below to compare the wiring of a
straight-through and a crossover cable.
Figure 5 Straight-through Cable/Crossover Cable
Normal Uplink Normal
Pin Pin
port port
1 1
Tx+
Rx+
2 2
Tx-
Rx-
3 3
Rx+
Tx+
4 4
5 5
6 6
Rx-
Tx-
7 7
8 8
Normal
Pin Pin
port port
1 1
Rx+
Rx+
2 2
Rx-
Rx-
3 3
Tx+
Tx+
4 4
5 5
6 6
Tx-
Tx-
7 7
8 8
15