Xref: utzoo comp.os.vms:9921 comp.dcom.modems:2888
Path: utzoo!attcan!uunet!ncrlnk!ncrcae!hubcap!gatech!rutgers!mailrus!purdue!decwrl!mejac!gryphon!pnet02!lewis
From: lewis@pnet02.cts.com (Lewis Dupran)
Newsgroups: comp.os.vms,comp.dcom.modems
Subject: Re: VMS modem woes
Message-ID: <8576@gryphon.COM>
Date: 9 Nov 88 06:40:15 GMT
Sender: root@gryphon.COM
Organization: People-Net [pnet02], Redondo Beach, CA.
Lines: 29

I originally had the same trouble with our VAX (using 64 of the Emulex DMF-32
ports).  I used a Hayes V.series 9600, Hayes V.series 2400, USR Courrier HST,
and six Mitsuba 2400 baud modems.  
Symptoms were the same as you described...  If the ports were configured
/modem/hangup (etc) the VAX would answer and dump the line.  Special note -
I had the modems in NON verbose mode...  the "RING" was NOT being sent by
the modems to fool the VAX, so this was not a factor.
Anyway, to make a long story short, I "bandaged" the problem by setting the
modems to answer on 1 ring, to not give result codes unless they are the
ORIGINATING modems, and on the Hayes 9600, I had the luxury of setting the
port speed to a constant 9600 regardless of the connect speed (the v.9600
has a built-in speed differential buffer).
The only problem after all this was that sometimes the modems would completely
lock-up, and they would be busy tx'ing and rx'ing in a deadlock even though
they were on-hook!  This gem was solved by enabling /syspassword so that
nothing (except a ^g) gets from the VAX to the modem until after a syspass
is humanly typed.
The only remaining problem now is that if a user loses carrier and gets
disconnected, the process does not "detach"...  it's as if they were hooked
up to a standard serial port.  An interesting experiment I did to try and
figure this out was to TURN OFF the modem while a user was in session on
it (nice guy, huh?).  The session proved to properly "detach" in that case.
Conclusion:  some wiring changes are needed in order to fully support these
beasts, and perhaps even an electrolytic capacitor to hold some pin up longer.
One of these days, I'll get around to taking off the bandage and actually
healing the wound.

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