Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!olivea!oliveb!pyramid!lstowell
From: lstowell@pyrnova.pyramid.com (Lon Stowell)
Newsgroups: comp.dcom.modems
Subject: Re: Modem Com analyzer wanted
Message-ID: <129901@pyramid.pyramid.com>
Date: 10 Oct 90 22:43:54 GMT
Sender: daemon@pyramid.pyramid.com
Reply-To: lstowell@pyrnova.pyramid.com (Lon Stowell)
Organization: Pyramid Technology Corp., Mountain View, CA
Lines: 21

For V.32 you will have the problems with training of the Echo
Cancellor as noted.  

You can use a FireBert from TTC to check the phone lines, you
can use a TAS to check the modems themselves for ability to
survive common impairments...

Frequently it is a matter of a too short carrier hold timing in
V.22bis /V.32 modems.....    Also the tendency of both of these
to retrain in the middle of transmission.  V.22bis modems may
take up to 0.7 to 1 second, V.32's may take up to 48 or more
seconds.   Darned few protocols and Front End Processors account
for these nasty tendencies.....THEY take the link down
prematurely while the modem is attempting to reestablish
commo...

You may wish to use an HP-4954 or Tektronix TC-2000 series
protocol analyzer to see whether the modems or the DTE's are
dropping prematurely....   as a general rule, if DSR drops
before DTR does, the modems did it.... If DTR drops before
either DSR or CxDet, the DTE on THAT modem did it.....