DTMF Simulator

Dual-tone multi-frequency signaling

Multi-frequency signaling is a group of signaling methods that use a mixture of two pure sine waves. The DTMF system uses a set of eight audio frequencies transmitted in pairs to represent 16 signals.

1 2 3 A Dial Tone
4 5 6 B Ring Tone
7 8 9 C Busy Signal
* 0 # D Error

A beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.

Tone 1: --Hz
Tone 2: --Hz
Beat Frequency: --Hz

Make Your Own

Choose two frequencies and see how they sound together.

Play