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From: zhahai@gaia.UUCP (Zhahai Stewart)
Newsgroups: comp.dcom.modems
Subject: Re: An interesting modem problem
Message-ID: <133@gaia.UUCP>
Date: Tue, 11-Nov-86 22:42:20 EST
Article-I.D.: gaia.133
Posted: Tue Nov 11 22:42:20 1986
Date-Received: Wed, 12-Nov-86 20:24:13 EST
References: <128@gaia.UUCP>
Organization: Gaia Corp, Boulder, CO
Lines: 21
Summary: More symptoms

Some more possibly useful information on the ~r and }i modem problem:
One modem is a Hayes 1200 which has had no similar problem in connecting
to many other modems over the last couple of years.  The other is a
2400 bps modem, operating at 1200 of course, which has not had the same
problem with anyone else.  The garbage chars are inserted every 10-40
seconds more or less, thruout a session.  Some connections are great,
some are terrible, a few are in between; a given session is pretty much
the same from start to finish.

Thoughts: it *might* have to do with adaptive equalization on the 2400
bps side, with some phone connections.  It might have to do with losing
sync in the pseudo random scramblers used with 1200 bps.  

I had an almost identical problem a couple of years ago with two modems
by different manufacturers from either of the ones currently involved.
(ie: 4 vendors' products total).  This leads me to suspect that it has
something to do with a weak area of the Bell 212A protocol, something
which is susceptible to marginal conditions of some sort.  Any help would
be appreciated.
	Zhahai Stewart    HiSystems
	nbires!gaia!zhahai