Re: Ethernet Cable Question

[Vidiot <brown ftms COM>]

>I'm trying to connect my laptop to my desktop (both linux) and have been
>told I can do this without a hub using crossover cable. So I am
>wondering what the difference is between regular ethernet cable and
>crossover cable?

Technically, twisted pair cable is not ethernet cable.  Ethernet, which was
developed by Xerox, only works on coax cable, first as think net and then
as thin net.

If you connect the two units together with coax, there is no crossover,
since you can't crossover coax :-)

If you use twisted pair, 10baseT or 100baseT, four of the wires are used to
carry the network connection.  One pair is for transmit and the second pair
for receive.  Think of the connection as if it were a serial port.  There is
the DTE end and the DCE end.  The same goes for twisted pair.  The computer
is like the DTE end.  It is expecting to connect to a hub, or DCE end.
If you connect two terminals together, you use a null modem that does the
crossover.  Well, when you connect two computers together using twisted
pair, you have to swap the Tx and Rx pairs on one of the end of the cable.
That is your crossover cable.

If you have the tools to make cables, it is easy to swap those pairs.  Otherwise
you have to purchase a cable that was specifically made as a crossover cable.

MB
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