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Path: utzoo!watmath!clyde!burl!ulysses!harpo!decvax!vortex!lauren
From: lauren@vortex.UUCP (Lauren Weinstein)
Newsgroups: net.flame
Subject: "half-duplex" phone connections
Message-ID: <261@vortex.UUCP>
Date: Mon, 27-Feb-84 00:40:15 EST
Article-I.D.: vortex.261
Posted: Mon Feb 27 00:40:15 1984
Date-Received: Wed, 22-Feb-84 02:08:22 EST
Organization: Vortex Technology, Los Angeles
Lines: 16

To the person who was screaming about "half-duplex" phone connections...

Look over the archives of the fa.telecom newsgroup.  Within the last
month I posted a detailed discussion concerning the why's of echo
suppression on long-haul toll circuits.  There are good reasons why
very long circuits are pseudo-half-duplex, and of course equipment
can get out of adjustment from time to time and cause problems.

New equipment is coming into use that will largely eliminate the need
for many blocking echo suppressors, but for now you'd usually be unable to
carry on an understandable conversation without them due to hybrid-induced
echo effects.  The circuits are actually full-duplex -- which is obvious
since modems work once they've turned off the echo suppressors with their
2225 Hz. answer tones.

--Lauren--