DTMF (Dual-Tone Multi-Frequency)
Click the buttons on the keypad to hear the DTMF tones (Flash 7).
There are twelve DTMF signals, each of which is made up of two tones from the following selection: 697 Hz, 770 Hz, 852 Hz, 941 Hz, 1209 Hz, 1336 Hz, 1477Hz.
The tones are divided into two groups (low and high), and each DTMF signal uses one from each group. This prevents any harmonics from being misinterpreted as part of the signal.
The following table shows the frequencies used for each signal:
|1209 Hz||1336 Hz||1477 Hz|
DownloadThe 12 DTMF tones are available for download in the following zip file (right-click and Save As): dtmf.zip
You can download the Flash touch-tone keypad here.