DTMF works by assigning eight different audio frequencies to the rows and columns of the keypad. ... When you press a key—which corresponds to a number or symbol—the phone generates a tone that simultaneously combines the high-frequency signal from the column that key is in with the low-frequency signal of the row it's in.

What is DTMF decoding?

Product Details. Dual-tone multi-frequency (DTMF) signaling is a standard in telecommunication systems. The DTMF decoder is typically used in telephone systems to detect DTMF tones in the incoming signal and convert them to actual digit.

How is DTMF signal generated?

Dual tone multi-frequency (DTMF) is the sounds or tones generated by a telephone when the numbers are pressed. These tones are transmitted with the voice channel. DTMF is used to control automated equipment and signal user intent, such as the number they wish to dial. Each key has two tones at specific frequencies.