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."