Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!epiwrl!parker
From: parker@epiwrl.EPI.COM (Alan Parker)
Newsgroups: comp.unix.wizards
Subject: Re: FCC doing it again...
Message-ID: <3012@epiwrl.EPI.COM>
Date: 28 Nov 89 23:05:39 GMT
References: <21536@adm.BRL.MIL> <1989Nov28.011514.4193@virtech.uucp>
Reply-To: parker@epiwrl.EPI.COM (Alan Parker)
Organization: Entropic Processing, Inc., Washington, DC
Lines: 18

In article <1989Nov28.011514.4193@virtech.uucp> cpcahil@virtech.uucp (Conor P. Cahill) writes:
>A modem phone call is not the same as a voice phone call.  Modem calls are
>continuously transmitting tones on the line, while a voice call has lots 
>of periods of silence.  This makes modem calls harder to multiplex on the 
>phone network than voice calls.
>

We've been through this before (a year or so ago).    Modern telephone
multiplex equipment doesn't depend on the amound of silence on the
circuit.   There was some multiplex equipment used for early undersea
cables that worked that way, but this isn't a factor for what you are
concerned about.   

Telephone mux equipment is either analog, in which case the circuit
(about 300 to 4Khz bandpass) is frequency shifted onto a carrier
frequency with a bunch of other circuits on different carrier
frequencies, or digital, in which case the 300 to 4K bandpass is
digitized and then time-domain muxed onto a faster circuit.