Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!apple!portal!sv!daven
From: daven@svc.portal.com
Newsgroups: comp.sys.mac.hardware
Subject: Re: Serial<->Serial Question
Message-ID: <1990Dec29.034218.24207@svc.portal.com>
Date: 29 Dec 90 03:42:18 GMT
References: <1990Dec27.231925.22246@bronze.ucs.indiana.edu>
Organization: Software Ventures
Lines: 42

In article <1990Dec27.231925.22246@bronze.ucs.indiana.edu> jbaron@silver.ucs.indiana.edu (Jeffrey Baron) writes:
>Well, I couldn't resist getting an big blue clone laptop (The only IBM
>I will ever buy - and the only laptop if Apple ever gets off their duffs
>and puts out a "Laptop for the Rest of Us"...).
>
>I just want to know if I need a Null modem adapter to hook the two serial
>ports together?  I once saw a diagram of a Null Modem adapter (MacWorld,
>I believe, no idea when or where) and it had a number of crossed wires in
>it (tab 'a' into slot 'b' sort of thing).  Just what does it do for a 
>living?

Yes, you will want to use a null-modem cable. It makes each computer look
like it's wired to a modem. MacWorld (or was it MacUser?) did have such
an article and diagram.

The wiring we recommen in our MicroPhone II manual is:

Mac DIN-8                                   PC
============                            ==========
(HSKo) pin 1  ------------------------> pin 5 (CTS)
(HSKo) pin 1  ------------------------> pin 6 (DSR)
(HSKi) pin 2  <-----------------------> pin 4 (RTS)
(TXD-) pin 3  ------------------------> pin 3 (RXD)
(RXD-) pin 5  <------------------------ pin 2 (TXD)
(TXD+) pin 6  ---x
(dead) pin 7  ---x
(GND)  pin 4  --------\
(RXD+) pin 8  --------/

Legend:      ---x  this pin connects to nothing
             <---  signal goes from PC to Mac
             --->  signal goes from Mac to PC

             ---\
             ---/  these two pins are jumpered together


-- 
-------------------------------------------------------------------------------
   Dave Newman              |  daven@svc.portal.com        |  AppleLink: D0025
   Sofware Ventures Corp.   |  AOL: MicroPhone             |  CIS: 76004,2161
   Berkeley, CA  94705      |  WELL: tinman@well.sf.ca.us  |  (415) 644-3232