Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!ogicse!milton!sumax!ole!ssave
From: ssave@ole.UUCP (Shailendra Save)
Newsgroups: sci.electronics
Subject: Re: smart fax
Message-ID: <1975@ole.UUCP>
Date: 3 Jun 91 04:32:32 GMT
References: <1118@xroads.UUCP>
Distribution: usa
Organization: Seattle Silicon Corp., Bellevue, WA.
Lines: 14

From article <1118@xroads.UUCP>, by schuch@xroads.UUCP (John Schuch):
> 
> 
> I was looking at a fax machine the other day and the flyer said it
> could tell if the incomming call was a fax or a voice. 
> How can it tell?

  Frequency. Digital messages work on two frequencies only. One for
  a high logic level, one for a low. A voice contains a lot of others.
  A simple notch filter to a voice detecting ckt would tell the
  difference.

> John
> hplabs!hp-sdd!crash!xroads!schuch