Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!iuvax!purdue!bu-cs!encore!xylogics!loverso
From: loverso@Xylogics.COM (John Robert LoVerso)
Newsgroups: comp.dcom.modems
Subject: Re: Microcom QX/V.32c evaluation
Message-ID: <6906@xenna.Xylogics.COM>
Date: 14 Aug 89 18:15:49 GMT
References: <361@larouch.UUCP> <12332@s.ms.uky.edu>
Reply-To: loverso@Xylogics.COM (John Robert LoVerso)
Organization: Xylogics, Inc., Burlington MA
Lines: 47

As another datapoint, I've had abysmal results with all the Microcom
modems I've tested.  Back in June, I had a pair of QX/V.32cs.  They
worked fine inside the building and from home.  I brought one with
me to the Baltimore USENIX and I couldn't get it to connect to its
twin sitting back here in our machine room, at ANY speed.  However,
an internal 2400 baud modem in a laptop had no problem talking to
the QX/V.32c back here, using the same phone line!  When I brought
the modem back here, it worked fine.

At the same time, we had flawless performace from the Telebit T2500s
that were being used in the terminal room.

> ...
> The [Baltimore USENIX] terminal room was run off a T2500 ... I don't
> know what baud rate and/or compression was used.
> ...

Just for the record, both sides were at 9600 and were using Van
Jacobson's header compression code, one end on a Sun3 and the other
on an Annex.  For most of the show, the Sun3 sitting in the terminal
room was using a SLIP link at 38400 to the Annex (since there was
no Ethernet at all in the room).

I recently had a pair of Microcom QX/3296s on evaluation.  These
do MNP.6, as opposed to the MNP.9 on the QX/V.32c.  They do have
a "uucp spoofing mode", or so the manual says.  It just lists the
command to turn it on, but says nothing about what it does.  I was
interested in trying it, given that the QX/V.32c was beaten by a
Trailblazer-Plus in terms of throughput over a UUCP connection.
When I first unpacked the QX/3296s, one of them was acting flakey
because about 99% of the time it wouldn't pick up the phone line
when given a dial command (i.e., it couldn't get a dialtone - I'd
hear the relay go off hook, but I'd get nothing on the speaker -
plugging in a phone got me a dialtone).  All of a sudden [no good
reason why - I hadn't changed any switches or configuration], it
started working fine.  I got the pair to work and was somewhat
satisfied with the performance.  I put the previously flakey one
in my machine room and took the other one home.  When I got home,
the modem would no longer pass self test.

To make a long story shorter - we're buying T2500s.  I've never had
problems like this with my Trailblazers.

-- 
John Robert LoVerso			Xylogics, Inc.  617/272-8140
loverso@Xylogics.COM			Annex Terminal Server Development Group
encore!xylogics!loverso			[formerly of Encore Computer Corp]