Key Tone Reading

[Guest barsby]

Developing some software for my university course. I need to know how you can read a tone in from a caller. Im making a kinda switch board. So for example if a caller presses 1 while in call, how can i read this in and do something that corresponds. (like ur answer machine where you press 1 to listen, 3 to delete etc.)

Cheers

matt

[Guest kam_]

afaik you will need to sample the incoming wave form and look for the dtmf frequency pairs. You can probably find some spectrum analysis examples on the web if you look in the right places.

[Guest awm129]

afaik you will need to sample the incoming wave form and look for the dtmf frequency pairs.  You can probably find some spectrum analysis examples on the web if you look in the right places.

<{POST_SNAPBACK}>

TAPI allows you to open a line device with different Media Modes (voice, tone, modem, etc...). I beleive TAPI can monitor the line and send you messages when certain tones are detected. No FFTs involved :-)

Edited February 28, 2006 by awm129