Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1+some 2/3/84; site dual.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!ut-sally!mordor!dual!paul
From: paul@dual.UUCP (Baker)
Newsgroups: net.followup
Subject: Re: Telecomm rates?
Message-ID: <825@dual.UUCP>
Date: Thu, 4-Oct-84 23:57:16 EDT
Article-I.D.: dual.825
Posted: Thu Oct  4 23:57:16 1984
Date-Received: Sat, 6-Oct-84 02:15:30 EDT
References: <3791@decwrl.UUCP>, <649@hound.UUCP>
Organization: Dual Systems, Berkeley, CA
Lines: 14

Central offices do not and do not need to know if a modem
is being used.  On the other hand Echo suppressors that are
used to prevent you hearing your own voice returned after a few
seconds on long lines, need to be disabled for a full-duplex 
Modem to work.  It does this by detecting the answer tone given
by the Modem.  Note that this is the same tone for all Bell
standard Modems.  Digital central offices  are in no better
position to interpret information passed through them.

There does seem to have been an interest in the past by phone
companies to try and charge Modem users more than voice users.  
So far none of them have been successful.

Paul Wilcox-Baker