Hi Guys, I'm looking to receive, and interpret DTMF. That's two simultaneous tone frequencies, I'm not completely versed with software detecting the frequency of just one tone. I think I'm somewhat arriving at a solution in my head without having hit the computer yet. Having used the audio out, I'm sure that using audio in, you'll end up with a sample buffer at known sample format, and am sure if I try, I'll get that far. What then? Are there any canned solutions for looking at the wave form to count peaks? DTMF produced by dedicated chips will be nice clean sine waves. I have a scope, and will be able to see that much. Cheers, Art.