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From: ames!ultra!ted@uunet.uu.net (Ted Schroeder)
Newsgroups: comp.dcom.telecom
Subject: Re: Modems and Phone Rates
Message-ID: <1799@accuvax.nwu.edu>
Date: 4 Dec 89 17:49:19 GMT
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X-Telecom-Digest: Volume 9, Issue 551, message 2 of 11


In this discussion nobody has mentioned the fact that modems place a
continuous carrier on the line, unlike human voices that pause between
sentences and words.  There is a form of compression called DSI (and
there may be other forms also) that allow this "dead space" to be
used.  You might put 12 calls on 8 lines and assume the "dead space"
would allow you to compress bandwidth this way.  I know this is done
quite frequently in fully digital private networks, but I don't know
how the public networks work and whether they use this type of
technology.

Does anyone out there know about this?


      Ted Schroeder                   ted@Ultra.com
      Ultra Network Technologies      ...!ames!ultra!ted
      101 Daggett Drive           
      San Jose, CA 95134          
      408-922-0100

Disclaimer:  I don't even believe what I say, why should my company?