Matlab code analyzing sound for Dual Tone Multi Frequency (DTMF) tones. I have reused a large part of this matlab code: http://nl.mathworks.com/help/signal/examples/dft-estimation-with-the-goertzel-algorithm.html
Soundfile dtmfA1.wav downloaded from: http://www.ee.columbia.edu/~dpwe/sounds/dtmf/ http://www.ee.columbia.edu/~dpwe/sounds/dtmf/dtmfA1.wav more soundfiles: http://www.ee.columbia.edu/~dpwe/sounds/
made some DTMF testfiles at: http://www.audiocheck.net/audiocheck_dtmf.php