Path: utzoo!attcan!uunet!altnet!ernie!animal
From: animal@ernie.NECAM.COM (Alan R. Silverman)
Newsgroups: comp.dcom.modems
Subject: Re: null modem cables
Summary: rs232 null modem
Message-ID: <137@ernie.NECAM.COM>
Date: 6 Sep 88 22:14:47 GMT
References: <8809030943.AA02215@ucbvax.Berkeley.EDU>
Organization: NEC America RATS, San Jose, CA
Lines: 29

In article <8809030943.AA02215@ucbvax.Berkeley.EDU>, A1T@PSUECL.BITNET (Andy Tefft) writes:
> 
>   - - The original note follows - -
> 
> Can anyone out there tell me how to make a null modem cable? I tried just
> connecting corresponding pins of my 2 serial connectors on 2 computers
> together, with the serial cards set the same way. No dice.
> 
> Please reply via e-mail unless you think others will be interested.
> 
> Andy Tefft


1  ->  1  Straight thru
2  ->  3  2 crosses to 3, and visa versa
3  ->  2
4  ->  5  4 crosses to 5, and visa versa
5  ->  4

6 -|	  6 shorts to 8 on the same side, then crosses to 20 on the
8 -|->20  other side

7  ->  7  Straight thru

20 --> 8
    |->6

Note: On VAX Modems, pin 22 is needed for ring indicator.
For more info, read RS232 Made Easy.  Good simple book.