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Decoding DTMF

Started by papgust August 9, 2005
hi all,
i need to write an application that listen for DTMF tones from
standard audio input (from the mic) and execute an action depending on
the digit extracted from the DTMF tone. Unfortunaly i have short time
to set up this application and i'm really new to this kind of problem
(sound analisys). I take a look at JTAPI but i don't have any
telephone in this context, i just have to analyze a normal sound
signal from the sound card. I found some applications on the net but
most of them need a modem and don't manage the input from the sound
card, the other are win apps and i cannot configure the actions.

I'm a java programmer so it would be nice if there's a library that i
can use and accept an audio stream in input and give the digit in
output ... if something like that doesn't exists i need at least a
java implementation of a DTMF decoder

thank you for your help



		
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papgust wrote:

> hi all, > i need to write an application that listen for DTMF tones from > standard audio input (from the mic) and execute an action depending on > the digit extracted from the DTMF tone. Unfortunaly i have short time > to set up this application and i'm really new to this kind of problem > (sound analisys). I take a look at JTAPI but i don't have any > telephone in this context, i just have to analyze a normal sound > signal from the sound card. I found some applications on the net but > most of them need a modem and don't manage the input from the sound > card, the other are win apps and i cannot configure the actions. > > I'm a java programmer so it would be nice if there's a library that i > can use and accept an audio stream in input and give the digit in > output ... if something like that doesn't exists i need at least a > java implementation of a DTMF decoder > > thank you for your help > >
Google ing for "java fft source" [ without quotes gives many on topic hits ] http://www.yov408.com/html/codespot.php?gg=35 may meet your needs. You specified no memory or speed restrictions. I can not vouch for code as I don't speak Java. Remember your signal *must* be sampled at *MORE* than twice highest frequency present. I'm sure others will give more efficient references. But if you need or can use 'quick and dirty' it may be useful. Signed, "a fellow newbie" [ Aside to Jerry, Rick and many other tutors here, I did not want to exceed my level of competence but thought references were enough to lead either to an "AHAA" experience or lead to understanding what questions should be asked. ]