3Com Gigabit Switch 8 User Manual page 23

Port Status LED not lit for a 10BASE-T port that has a
connection. There is a problem with this connection.
Check that you are using a straight-through 10BASE-T cable
which is properly connected at both ends, and is not
damaged. If the cable is connected to port 8, ensure that
the Uplink/Normal switch is set to Normal (out). Also check
that the equipment being connected to the hub is powered
on and operating correctly. Refer to Figure 9 below to
compare the wiring of a straight-through and a crossover
cable.
Figure 9
Straight-through Cable/Crossover Cable
Normal
Pin Pin
port
1 1
Rx+
2 2
Rx-
3 3
Tx+
4 4
5 5
6 6
Tx-
7 7
8
8
Uplink 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
Normal
port
Rx+
Rx-
Tx+
Tx-
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