- FAST ETHERNET SWITCH MODULE USER GUIDE 3H02-04, 3H08-04

Fast Ethernet Pin Assignments

FE Switch Module User Guide Page B-3

B.3.2 Crossover Wiring for the 3H02-04

Two Ethernet 100BASE-TX devices can communicate only if the

transmitter on one device is connected to the receiver on the other device.

This reversal, or crossover function, can be implemented either in the

wiring or in the device itself. The 3H02-04 contains an internal port

crossover on the second connection of each port. This means that you can

choose to use either crossover or straight-through cabling.

When connecting two identical twisted-pair ports (i.e., both crossover

ports or both straight-through ports), you must implement a crossover in

the wiring. Refer to the following table for crossover wiring conﬁguration

for the 3H02-04.

*The “+” and “–” signs are used to represent the polarity

of the two wires that make up each wire pair.

Table B-4 RJ45 Crossover Pin Assignments

RJ45 Pin Assignment

1 Tx+

2 Tx–

3 Rx+

6 Rx–

Table B-5 Crossover RJ45 Wiring Configuration

Hub (pin number) Device (pin number)