Path: utzoo!utgpu!watserv1!watmath!att!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!samsung!uunet!clyde.concordia.ca!ccu.umanitoba.ca!umcarls9
From: umcarls9@ccu.umanitoba.ca (Charles Carlson)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Mac to IBM PC-AT cable
Keywords: Macintosh, IBM, cable
Message-ID: <1990Sep10.041905.26363@ccu.umanitoba.ca>
Date: 10 Sep 90 04:19:05 GMT
References: <6368@jhunix.HCF.JHU.EDU>
Organization: University of Manitoba, Winnipeg, Canada
Lines: 57


In article <6368@jhunix.HCF.JHU.EDU> hsu_wh@jhunix.HCF.JHU.EDU (William H Hsu) writes:
>
>     I am trying to solder up a cable to connect my IBM 286 AT
>clone (a CompuAdd 286-12, purchased in December of 1988) to a
>Macintosh SE.  By "connect" I mean that I would like to transfer
>text and other files modem-style between the computers (I have
>modems on both ends, but one is a 1200 baud and one a 2400, so
>I'd prefer to bypass them both) using only the telecom software
>on each machine.  I surmise that this requires a male mini DIN-8
>connector on the Mac end, but am not certain whether I have the

Save yourself some frustration.  If you're not very good at soldering,
you'll never be able to solder wires to a mini din-8 connector.  
The best thing to do, which is what I did, is to just buy a standard
Macintosh modem cable, and a null modem adapter.  Plug it all together
all you'll be up and running in 10 seconds.

>..but am not certain whether I have the
>I/O hardware on the AT end to support a "null modem" connection. 
>In one of the expansion slots is an I/O card which came with the
>machine, containing one female DB-25 port (apparently a parallel
>port - a dot matrix printer is currently connected to it) and one
>male 9-pin port which the CompuAdd salespeople insist is NOT a
>serial port.  I see no other place where, say, a serial mouse

If its on this i/o board as you say, then it is a serial port.  Serial
ports either use a 9 pin male or 25 pin male.  CGA, EGA, and TTL video
use a 9 pin female.
Parrallel uses a 25 pin female, and game ports use a 15 pin female.
Ask your CompuAdd saleman what HE thinks it is, just out of curiousity :)

If you want to add a mouse as well, I recommend getting a second serial
port.   Most every i/o card made in the last several years has
an option to put a 2nd port on it.  All you need is 3 chips and a cable, 
and these are usually sold as a set for $15 or so.  You may even have this
option already.   If you're really unsure, call the CompuAdd tech people
in Auston and make sure.


>of MacUser, I am a little leery of trying to make the connector
>myself.  On the other hand, the fifty-odd-dollars that I have
>seen "custom-made-cables" advertised for seemed a little steep -

You won't have to pay over $25 for the cable and adapter, none of this
is custom and can be bought off of the shelf.  Check your local university
computer supplier.  This university sells Mac cables for about half as much
as the regular Apple dealers sell them for, and they are the exact same thing.


>I had thought this would be a pretty popular connection!  Perhaps

It is! 

Give a shout if you need more help.

Charles