DTMF tone detection during incoming oncall in iOS

I'm trying to call a number and send some data over call, that data is received as DTMF tone(Keypress tone) on another end. I want to decode that DTMF tone during oncall. I know there would be no official way of doing it, and certainly not for an App Store application, Is it possible to decode the DTMF code in iOS or android? Thanks in advance!