dtmf

dual-tone multi-frequency

DTMF (Dual-tone multi-frequency) tones are the sounds generated by touch tone phones. When a key on a phone keypad is pushed not one but two different frequencies are generated, hence the name dual tone multi frequency. DTMF is also known as tone dialing as opposed to the older pulse dialing.

Each of the 12 keys on a touchtone phone generates a different DTMF. String together the various DTMF tones and you can dial a number.

Click on the name of each DTMF tone hear it. Right-click on it to save the MP3 file to your hard drive.

DTMF 1 = 697 Hz & 1209 Hz
DTMF 2 = 697 Hz & 1336 Hz
DTMF 3 = 697 Hz & 1477 Hz
DTMF 4 = 770 Hz & 1209 Hz
DTMF 5 = 770 Hz & 1336 Hz
DTMF 6 = 770 Hz & 1477 Hz
DTMF 7 = 852 Hz & 1209 Hz
DTMF 8 = 852 Hz & 1336 Hz
DTMF 9 = 852 Hz & 1477 Hz
DTMF 0 = 941 Hz & 1336 Hz

DTMF * = 941 Hz & 1209 Hz
DTMF # = 941 Hz & 1477 Hz

DTMF busy signal = 480 Hz & 620 Hz
DTMF dial tone = 350 Hz & 440 Hz
DTMF ringback tone (US) = 440 Hz & 480 Hz

click to hear each DTMF tone

Each DTMF tone is 1 second long. To simulate dialing a number on a phone keypad, play the individual DTMF tones in the correct sequence.

If you're interested in DTMF tones you probably want to read about the Capn Crunch Whistle and the wiretap C tonetoo. Two phone phreaking boxes are related to DTMF tones: the blue box and the silver box.

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