DTMF Decoder module with chip for ArduinoDESCRIPTION Decodes DTMF audio signal to 4 bit binary TTL level output with LED indication. Suitable for use with microcontroller applications. This is a MT8870 DTMF Decoder Module. The module offers a 3. 5mm audio connector to connect an audio source. The DTMF Signal in the audio source is decoded and the digital outputs on the module, indicate the key pressed. You may connect a phone to the module and the module will output the key(0 9, *, #, A, B,