Ref: 13390011
Title: Connecting two MultiConnects using 10BaseT Devices
Date:    6/8/90

Copyright 3Com Corporation, 1991.  All rights reserved.

When you connect two MultiConnects together directly using 10BaseT,
note that the Link Integrity test (the green LED on the 3Com module)
requires that two 10BaseT transceivers be connected together so that
the receive pair of one ties to the transmit pair of another, and vice
versa.

The Etherlink/TP 3-port module performs the transmit-receive
crossover onboard, so external crossover is only required when connecting
to another 10BaseT device having internal crossover.  In most cases,
your 10BaseT module will be connected to a 10BaseT adapter (which
has no internal crossover), and external crossover is not required.
However, in the special case of connecting two 3-port modules together,
you must externally cross over the wiring or else the transmits will be
connected together and the receives will be connected together.

An easy way to tell if you need external crossover is to count the internal
crossovers on your end devices.  If the number is odd, do not cross over
the connecting wire.  If the number is even, cross over the connecting
wire.
