DTMF Decoder

DTMF Decoder can process dial tones generated by touch tone phones and log the corresponding phone number. The tone signal is extracted from the telephone line or radio receivers and forwarded to the computer's soundcard for processing.

What this application actually does is identify captured sounds and detect their frequencies in order to associate them with a certain key on the phone's number pad. As such, it can reveal the phone number that was dialed and the call time.

Before using it, you must configure the audio capture device (for instance, a microphone that your computer is equipped with) and adjust the audio mixer settings.

The main window includes two green bars that capture incoming tones, each having assigned different frequency ranges. In order for the application to work properly, the threshold (represented by the red line) must be set correctly. To be more specific, a tone is considered valid when its level exceeds the threshold with approximately 6 dB.

Please note that a change in the volume configuration of the soundcard requires the threshold to be re-adjusted, since the captured tones will have a different level.

DTMF Decoder includes a test example that can be used for assessing its capabilities and learning how to use it. Also, it allows you to configure the minimum tone and break time.

The captured data is automatically saved to a text file that can be saved to your computer for later reference.

DTMF Decoder can be used by audio and forensinc technicians to detect the dialled phone numbers. Configuring it is not difficult, especially for those who have a bit of know-how in this field.