[matthiasl]

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)