Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!van-bc!rsoft!mindlink!a544
From: Rick_McCormack@mindlink.UUCP (Rick McCormack)
Newsgroups: comp.sys.mac.comm
Subject: Re: Need help connecting Tandy 200 to Mac 512K
Message-ID: <4898@mindlink.UUCP>
Date: 23 Feb 91 13:30:31 GMT
Organization: MIND LINK! - British Columbia, Canada
Lines: 53

In an article Jeffrey Baron <jbaron@silver.ucs.indiana.edu> asks about:

 >     I have here a laptop IBM with a 9 pin AT serial port.
 >      >     I also have here a Mac Plus.  Between the two I have a din8
 >     to 9pin printer cable.  I have a Null modem adapter (Radio
 >     Shack) tossed into the line.  On the IBM end, I have Procomm
 >     or Bitcom.  On the Mac end, I have Microphone or Red Ryder.
 >     Everyone agrees that the Null modem will simulate a modem
 >     between the two machines, and I have done the following:
 >      >     On bitcom, ignore DSR (ignore the fact that Ma Bell isn't
 >     there). In fact, I have tried every combination of line
 >     settings I could find on the four different programs.
 >      >     Take two modems (one 1200, one 2400), connect with a phone
 >     line. On a Mac 512ke, do a 9pin seriel to 9pin seriel (mind
 >     you, when I put the Null modem adaptor anywhere near the
 >     512ke, the machine was reduced to a paperweight with asthma-
 >     it went totally dead, and made a noise like a leaky air
 >     hose.  It was ok once I removed the adaptor, though).
 >      >     On all these cases and more, the two failed to recognize the
 >     other's existance. I've had speculation before, and I thank
 >     all those who offer it.  What I want now is experience.
 >     Somebody has used this configuration, and knows what one can
 >     do with the aforementioned resources.

I routinely connect my pc-clone to a Mac plus set up in the same room.  The Mac
has a 2400 bps external, and the pc a 1200 baud internal.  I use Procomm on the
pc and Red Ryder on the Mac.
Both modems are connected to a Y-adaptor that enables either one to use my
telephone line.  I pull this adaptor out of the wall, and the two computer
modems are effectively joined thru the modems, without any possibility of
talking to the outside world.

Like this:      |PC|-|modem|----|Y-Adapt|---|Modem|--|Mac|

Start both computer comms programs.  I use ATHA on the PC, then ATH on the Mac,
but either one can Answer or originate.  The main things to change are the echo
and duplex setups, and I tackle them once the connection is made. (I use the pc
on a few special boards and its settings may vary from the 8N1-Full settings of
the Mac by quite a bit.)  I have used this setup several times to transfer
files of 10s of Ks, at 1200 bps between the machines.  Not the fastest, but it
is consistent, reliable and cheap, and I don't need anything else to do it
everytime.

I hope this helps: the main thing is to set one comm program to answer mode
when it goes on-line with the ATHA, and then, within the carrier detect time to
get the other computer on-line in the originate mode with ATH.
PS  I did run into one modem that required the sequence ATH1A rather than ATHA.
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