Path: utzoo!attcan!uunet!crdgw1!rpi!zaphod.mps.ohio-state.edu!usc!apple!netcom!teda!ditka!mcdchg!laidbak!obdient!vpnet!cgordon
From: cgordon@vpnet.chi.il.us (Gordon Hlavenka)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: help decoding touch-tones
Message-ID: <26a1da98-1f.1comp.sys.ibm.pc.hardware-1@vpnet.chi.il.us>
Date: 16 Jul 90 17:55:07 GMT
References: <1990Jul10.220135.22660@cbnewsi.att.com>
Lines: 11


>Has anyone decoded touch-tones off a phone line?

There are many ICs which do this.  I know Radio Shucks sells one for around
$10.  The chip runs on a color burst crystal (3.58-ish MHz) and produces hex
output from audio input.  Use an isolation transformer with a series cap on
the phone line side to grab the audio.  Be sure to put some clamping in
there!  An incoming ring is 90 - 130 vac!
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Gordon S. Hlavenka                 cgordon@vpnet.chi.il.us
Disclaimer: He's lying