3 ms·
Definitely click on the second to last icon on the bottom of the SPECTROGRAM page to see the spectrogram applied to an old POTS modem dialing out to another mod
by tmoertel 6y ago
Definitely click on the second to last icon on the bottom of the SPECTROGRAM page to see the spectrogram applied to an old POTS modem dialing out to another modem. Notice in particular that the DTMF touch tones are indeed composed of two tones.