Point-to-point networking

Maurice Hilarius maurice@harddata.com
Wed Nov 4 13:24:47 1998


With regards to your message at 09:58 PM 11-04-98 +0800, David R. Kohel.
Where you stated:
>After this initial success, I tried to hook up to a RedHat 
>DEC Alpha with built-in ethernet card.  I thought I could 
>just plug the two together with twisted pair cable.  
>Susequently I thought that I had been naive, that I needed 
>a hub between the two.  I admit am a network newbie, but can 
>read HOWTO's.  On this point I didn't find any clear information.  
>The LinkSys card's manual says it is not advisable to connect 
>two "PC's" together without a hub, as the connection might 
>be "unstable".

To direct-connect 2 cards together you simply need a "crossover" or "null"
cable.
This is one with the lines "crossed over" in the following fashion:

1	to	3
2	to	6
3	to	1
6	to	2

Key:
1 = TX+
2 = TX-
3 = RX+
6 = RX-

As you can see this is similar in concept to a null modem cable, where we
are connceting the send on one side to the receive on the other side.

All other lines do not need to be ( should not be) connected.


Best regards,

  Maurice W. Hilarius                   Telephone: 01-403-414-9319
  Hard Data Ltd.                      **FAX:       01-403-456-1510
  11060 - 166 Avenue                    email:maurice@harddata.com
  Edmonton, AB, Canada  - T5X 1Y3       http://www.harddata.com