I have a requirement to talk to hardware over PSTN using only DTMF. I have searched but no platform (IOS, Android and Windows 8) allows applications to control a call.
How can I make manual phone call and send/receive DTMF tones? Is there any solution or workaround for all these platforms?
The last time I looked into something like this, there were no (or equivalent to) cm5089 chips in the digital handsets to even produce the tones for DTMF. You can do the conversion to just audio like they do now but then I’d still be curious how to get your output over as audio input. Cool question, wish I had an answer though!
still could not find any workaround