Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!gatech!gitpyr!byron
From: byron@pyr.gatech.EDU (Byron A Jeff)
Newsgroups: sci.electronics
Subject: Re: DTMF Encoding AND decoding
Message-ID: <7171@pyr.gatech.EDU>
Date: 28 Jan 89 15:48:36 GMT
References: <350@serene.UUCP>
Reply-To: byron@pyr.UUCP (Byron A Jeff)
Organization: Georgia Institute of Technology
Lines: 30

In article <350@serene.UUCP> gbell@pnet12.cts.com (Greg Bell) writes:
>
> 
>   
> 
>     Are there any available chips to do both encoding AND decoding of DTMF in
>the same DIP?   Would save some board space.

Silicon Systems Inc. has such a beast. It's called the SSI 20C90 DTMF
transceiver with call progress detection. It generates and receives all
16 DTMF digits, has a micro interface and an "imprecise" call progress
detector. The only external components are a 3.57 Mhz "colorburst" crystal
and a resistor. It's a low power CMOS part in a 22 pin DIP.

The call progress detector simply activates a signal when the tone is in
the  305-640 hz band. It's up to the microprocessor to figure out what
the signal means.

Never used one of these but it looks like a nice part.

>    Greg Bell_________________________________________________________

I'm in no way associated with SSI except for being a satisfied customer.

BAJ
-- 
Another random extraction from the mental bit stream of...
Byron A. Jeff
Georgia Tech, Atlanta GA 30332
Internet:	byron@pyr.gatech.edu  uucp:	...!gatech!pyr!byron