【實用通訊app】DTMF Tone Extractor Pro|最夯免費app-綠色工廠好玩App

ToneExtractor can decode DTMF (dual-tone, multi-frequency) signals back to numbers

The following are the frequencies used for the DTMF system, which is also referred to as tone dialling. The signal is encoded as a pair of sinusoidal (sine wave) tones which are mixed with each other. DTMF is used by most PSTN (public switched telephone networks) systems for number dialling, and is also used for voice-response systems such as telephone banking and sometimes over private radio networks to provide signalling and transferring of small amounts of data.