Answering Machine on Android Playing audio to telephony uplink is possible, but the microphone input data is also transmitted.


How to switch off microphone on Android devices?
Is there a possibility to play audio to telephony uplink while call on mute?
I have been developing my own answer machine application and hit two major stumbling blocks. One is that setMicrophoneMute(boolean on) simply doesn't work. And the other issue is playing an audio greeting down the phone line. 

This isn't possible due to hardware restrictions and it doesn't even work if the microphone is switched on and the audio is played through the speakers.