[Asterisk-Dev] Food for thought in future versions: User-specified tone sequence recognition

John Todd jtodd at loligo.com
Mon Feb 2 07:22:25 MST 2004

>Would making dsp.c flexible enough to check and recognize user defined tone
>sequences in asterisk channel variables be something which could prove
>beneficial for several applications?
>I can think of a few:
>1. Pager prompt tone detection.
>2. Burglar alarm central station receivers.
>3. Coin telephone denomination detection.
>4. SIT tone detection
>5. Unusual/Obscure/Special call progress tone detection.
>Looking at the code in dsp.c, things are pretty convoluted at the moment
>maybe in the longer term we could rewrite it to allow the addition of
>user-defined tone sequences.

It would also ease the process of making an automated alert system to 
check on end-to-end status.  Every N minutes, an automated process 
would call several numbers (long distance) which were known to answer 
with a certain tone set.  Then the system would make sure it "heard" 
those tones, or else it would send of an alarm of suspicious 
end-to-end failures.

I don't know about the state of dsp.c, but it certainly would be nice 
to have some more flexibility for detection of tones within the audio 
stream to trigger Dialplan events.  Heck, even just the ability to 
press keys other than "#" in a conversation would be great!   See my 
notes on what I'm talking about here:



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