Advanced PlacementCollegeHigh School / Physics

Decoding DTMF Tones

Students will use a wireless sound sensor and the fast Fourier Transform (FFT) display of the data collection software to analyze the tones produced when dialing a phone. They will uncover the pattern of these dual frequency tones showing the first frequency gives the row of the key on the numeric keypad and the second frequency gives the column. From this information they can determine what key is pressed without seeing it.

Source: Physics Lab Station Investigations


Student Files

Decoding_DTMF_Tones_S.docx 81.81 KB
Decoding_DTMF_Tones_S.pdf 121.32 KB

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Wireless Sound Sensor

The Wireless Sound Sensor measures sound wave forms and sound level in one compact and portable sensor.

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