Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!UNCG.BITNET!ADCDRW%SPEEDY
From: ADCDRW%SPEEDY@UNCG.BITNET ("Don Wright, AdCC, x5835")
Newsgroups: comp.os.vms
Subject: RE: Re: DECSERVER 200's and dial in/out modems
Message-ID: <8801140022.AA02651@ucbvax.Berkeley.EDU>
Date: 13 Jan 88 02:11:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 46

> >
> >We are currently using Gandalf SAM224 modems on our decserver 200's to
> >provide both dial in and dial out services.  However there are lots of
> >problems getting the baud rate to change correctly when you connect to
> >a 1200 baud only site.  We can get the modems to work at 1200 or 2400
> >but not both when used for dial out, dial in seems not to be a problem.
> >
> > [....]
> >
> >Thanks in advance, Lawrence.
>
>Lawrence,
>
>I hate to break the bad news to you but I posted this problem on the net
>a while back...we all (to my knowlege) came to the conclusion that it could
>not be done.
> [...]
>

Well, I do know if *one* way....  What I've done is to use a modem which can do
speed conversion (FOUL!).  I'm using the Multi-Tech 224 EH modems which have
MNP error correction.  As an added bonus with the error correction option, you
get the ability to configure the modem's serial port speed to function
independently of the modem's actual communications speed.  In other words, you
can have the modem taking to the other modem at 1200 while the modem talks 2400
to your decserver.

So then all you gotta do is set up your decserver port to autobaud DISABLED and
set the speed to match the serial port speed on the MODEM and let the modem
handle the differences in speed both dialin and dialout.

At our site, when you dial in, the modem first wakes up at 2400, drop to 1200,
300, and finally 110 (gag) until it matches the originating modem.  Due to the
speed conversion inside the modem, the decserver port always sees 2400. On
dialout, the decserver port and the serial port on the modem still remain at
2400 and the communications speed of the modem matches whatever it hooks to --
again the modem speed conversion doing all the work.

I don't have any experience with other modems with this feature; maybe other
MNP modems work similarly (?).  Hope this has helped.

Don Wright
VAX Systems Manager
Administrative Computer Center
University of NC at Greensboro
WRIGHTD@UNCG.BITNET