Hi,
I'm trying to use el_supremo's DTMF library. No matter what I do, I can't get a reading/signal from it.
I am wiring up the handset output of my telephone with this schematic:
Taken from: https://coolarduino.files.wordpress.com/2011/02/dc_bias11.png
I know this circuit is working because other libraries that do different things correctly analyze the audio.
Is there something I need to change? I would prefer not to by a DTMF Decoder.