djo7613@blake.acs.washington.edu (Dick O'Connor) (12/28/88)
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
pjh@mccc.UUCP (Pete Holsberg) (12/30/88)
There may be a problem with COM2. Try removing the AST and using COM2
for the modem. Then COM1 if COM2 still doesn't work.
Pete
--
Pete Holsberg UUCP: {...!rutgers!}princeton!mccc!pjh
Mercer College CompuServe: 70240,334
1200 Old Trenton Road GEnie: PJHOLSBERG
Trenton, NJ 08690 Voice: 1-609-586-4800leonard@bucket.UUCP (Leonard Erickson) (12/30/88)
In article <464@blake.acs.washington.edu> djo7613@blake.acs.washington.edu (Dick O'Connor) writes:
<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 ran into a similar problem a few months back. In my case, the machine had
a mainframe terminal emulator board in it that used INT 3 *and* INT 4.
This made use of a serial board impossible at anything over 1200 bps. But
the *real* kicker was that the TSR *program* for talking to the mainframe
caused the exact problem you describe. Characters being sent, but nothing
displayed.
I'd check his software and see what he has that has latched onto the
COM interrupts. The sysmptoms fit perfectly. Some sort of TSR is grabbing
the incoming characters for itself.
--
Leonard Erickson ...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I used to be a hacker. Now I'm a 'microcomputer specialist'.
You know... I'd rather be a hacker."fleming@uxh.cso.uiuc.edu (01/04/89)
I had a similar problem twice with an Everex Modem. I had hooked the wall line into the wrong jack on the modem, and subsequently put the phone in the wrong jack, too. Voice worked, and I could make a connection to the remote computer, but no communication could take place. This maybe too simple a fix, but it drove me nuts for quite some time. Declan J. Fleming
djo7613@blake.acs.washington.edu (Dick O'Connor) (01/05/89)
I'm amazed at the number of responses I received concerning the problem I was having with a PC's Limited AT and a serial port that wouldn't respond correctly to a working external 1200 baud modem. Thanks Pete, Leonard, Mike, Cris, Rich, Thomas, Jim, John, Bill, and Tom; some of you hit it right on the nose, others were awfully close. A couple of you were interested in the final result, so I'm posting the solution we arrived at after intense absorption of the DIO-200 I/O Card manual. The user was trying to use the primary serial port (serial port #1) as COM2 because he had a laser printer assigned to COM1. This is OK as long as you change the default switch and jumper settings on the I/O card to reflect this. To get the serial port to respond as COM2, the interrupt jumper must be set for IRQ3 (not IRQ4, the default), and the switch settings change from the default ON ON to ON OFF. One of these things wasn't set correctly, and when he set the both in synch, everything was beautiful. Moral: Yes, yes, ReadTheFriendlyManual; however, I still think I/O card documentation could improve a *lot* with the addition of a few "scenario" style examples. "Chip has a laser printer assigned to COM1 and wants to add a modem to COM2. In this case, he simply..." Thanks again, netfolk, for your swift and helpful responses!!! -Dick O'Connor Washington Department of Fisheries Disclaimer: Well,...they approve of this posting, I'm sure! P.S. Apologies to Bill Maine, Tom Thackeray, and John P. Nelson; tried to mail my thanks to you, but I must have copied your addresses incorrectly and our local mailer balked.