Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!gatech!ncar!ames!hc!lanl!cmcl2!phri!cooper!gene From: gene@cooper.cooper.EDU (Gene (the Spook) ) Newsgroups: sci.electronics Subject: Re: Need DTMF Decoder/Ringing Detector Message-ID: <1352@cooper.cooper.EDU> Date: 13 Jul 88 17:33:05 GMT References: <5317@super.upenn.edu> Distribution: na Organization: The Cooper Union (NY, NY) Lines: 27 in article <5317@super.upenn.edu>, zielke@eniac.seas.upenn.edu (Stephen Zielke) says: > > 4. Dectecting the DTMF touch tone signals is the main problem. There are > plenty of DTMF encoders that are used in the telephone (accepting > signals from a keypad). But the DTMF DECODER, which would be present > in the central office, seems to be more difficult to find. Anyone know > where to get one of these chips? Sure. Radio Shark used to carry (maybe they still do) a DTMF decoder chip for a few bucks. If you can get your hands on one of them, fine. What I've used before and enjoyed playing with is a neat chip from Mitel (Boca Raton, FL). They have quite a few versions. For example, one is strictly a DTMF decoder, another has both an encoder and decoder on-chip, and both are easily microprocessor interfaceable, to coin a word. Give Mitel a call. If you're nice, they'll be happy to send you a data book, and MAYBE even a sample of the part you're interested in. By the way, the number of the chip I've used is an MM8870, I think. Talk with someone in sales, and they'll steer you in the right direction. As Confucius say, Good Ruck! Spookfully yours, Gene "Rock is my religion; Judas is my Priest."