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Posting-Version: version VT1.00C 11/1/84; site vortex.UUCP
Path: utzoo!linus!decvax!bellcore!vortex!lauren
From: lauren@vortex.UUCP (Lauren Weinstein)
Newsgroups: net.dcom
Subject: Re: Telco Hassles
Message-ID: <843@vortex.UUCP>
Date: Sat, 19-Oct-85 22:37:33 EDT
Article-I.D.: vortex.843
Posted: Sat Oct 19 22:37:33 1985
Date-Received: Mon, 21-Oct-85 06:11:54 EDT
References: <848@mcvax.UUCP>
Organization: Vortex Technology, Los Angeles
Lines: 26

First of all, I note that the original poster said the problem was with
a 202C type modem.  This is a half-duplex modem, not used in "normal"
applications with Unix, and implies that some specialized application
was in use.  But in any case, regardless of the type of modem
or the application that was running, the original poster said that the 
computer on one end was rebooted, dropping all the dialup lines, at 
intervals considerably shorter than the period of time telco claimed the 
call was in progress.

This would seem to absolve software on those machines of responsibility
for the problem.  If the modem on either side hungup, the phone connection
would be broken (and charging stopped) within 30 seconds or less.

One likely possibility is that a modem on one side or the
other triggered remote self-test mode among both modems.  Depending
on the modems, this can sometimes cause even DTR to be IGNORED.
Some modems spontaneously drop in/out of this mode under certain
conditions.  I've seen a pair of modems merrily chattering at each
other for hours even when the systems at both ends were completely
down and DTR was down on both modems.  Suddenly, both modems just cleared
and went back to normal.

The moral is to ALWAYS jumper OFF remote self-test mode within
the modems!

--Lauren--