Tip: Click and hold any button to play the tone. Release to stop.
What is DTMF?
Dual Tone Multi Frequency (DTMF) is the signal system used by touch-tone telephones. Each key press generates two simultaneous tones - one from a low frequency group and one from a high frequency group.
The combination of these two frequencies uniquely identifies which key was pressed, allowing the telephone system to recognize the input.
Frequency Groups
Use Cases
- • Telecommunications: Phone dialing systems
- • IVR Systems: Interactive voice response
- • Testing: Phone system diagnostics
- • Education: Learning about signal processing
- • Ham Radio: DTMF control systems
Technical Details
- • Each tone is 50ms minimum duration
- • Tones are sine waves (pure frequencies)
- • Used in landline and mobile networks
- • Replaced rotary dial pulse dialing
- • Also known as "Touch-Tone"
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