Phone keyboard number detector
DTMF stands for Dual-Tone Multi-Frequency Signaling, designed for communication between telephones and telecommunications centers. In DTMF, for each of the 12 keys on the phone, a special signal is sent so the receiver determines which key is pressed. For each key, a combination of two sine signals is sent, whose frequency is given in the table below.
so I use Python to simulate DTMF.