659 8890 That one's just ordinary DTMF. I recorded the audio, trimmed it manually and then made a spectrogram like this: sox gun1.wav -n rate 4k spectrogr

659 8890 That one's just ordinary DTMF. I recorded the audio, trimmed it manually and then made a spectrogram like this: sox gun1.wav -n rate 4k spectrogram -m -y 500 The 'rate' switch is to cut down on how much of the frequency space we can see. I left the audio as stereo because there's less music power on one channel, making it easier to see the tones. (And google finds quite a few pages confirming those digits)