Path: utzoo!attcan!uunet!husc6!ogccse!blake!djo7613
From: djo7613@blake.acs.washington.edu (Dick O'Connor)
Newsgroups: comp.sys.ibm.pc
Subject: PC's Limited AT Serial Port Problem
Keywords: PC's Limited, serial port, modem
Message-ID: <464@blake.acs.washington.edu>
Date: 28 Dec 88 15:58:01 GMT
Organization: Univ of Washington, Seattle
Lines: 30

A co-worker has just decided to try dialing in to the agency's Prime
computer from home (to burn some midnight oil, no doubt!).  He is
having problems making connections.  I'm somewhat experienced with
doing this, as I do it from home all the time.  But I think there must
be something I don't know about PC's Limited AT micros, and I'd
appreciate any pointers as to what is going wrong.

He's using the above computer with an AST TurboLaser printer connected
to COM1 and a Prometheus 1200 baud external modem connected to COM2.
The software is Procomm 2.4.2, and he has the protocol correct (1200N81).
In response to the dialing command, the modem goes offhook, dials the
number, gets the response, carrier detect comes on with all the right
tone noises, and then nothing appears on the screen (where a Please
Log In message should appear).  In response to <RETURN>s, the RD 
(Read Data) light on the modem blinks long enough to indicate characters
are being sent down the line, but there is no display.  I replaced the
modem (which we tested at work on Zenith Z248 machines; no problems!)
with a Tandy internal similar to the one I use at home, and got similar
results.

I really don't know anything about the fancy IO board these machines use
(his is 2.5 years old, back before they became Dell Computers), but the
serial ports seem to be straightforward.  Is the presence of the laser
printer causing interrupt stealing or other conflicts?  Disconnecting
the printer cable didn't have any effect on this problem.  Any ideas,
oh battle-scarred veterans of the Serial Wars??  Thanks.

-Dick O'Connor
 Washington Department of Fisheries