3Com EtherLink III ISA User Manual page 90

C-2 A C: C
PPENDIX
2
To make a crossover cable, connect TD+ to RD+ and
TD– to RD–.
The cable performs the crossover that is usually performed by the
hub. Figure C-1 shows the pinouts for the crossover cable:
.
Straight-through
10BASE-T cable
1
2
3
4
5
6
7
8
Figure C-1 Straight-Through and Crossover Cable Pinouts
If the file server and client PC function together as a small
network, then either the existing cabling or the hub is failing.
With a correct crossover connection, the LED lights.
I
With a straight-through connection, the LED does not light.
I
With a polarity mismatch (that is, TD+ to RD– instead of TD+
I
to RD+), the LED blinks.
C T
ROSSOVER ABLE ROUBLESHOOTING
1 2 3 4 5 6 7 8
1 TD+
TD
2
3
RD+
4
5
6 RD
7
8
T
IPS
Crossover
10BASE-T cable
1
2
3
4
5
6
7
8
1 TD+
TD
2
3
RD+
4
5
6 RD
7
8