Sending Data through Headphone jack in Android phones

Question

I\'m currently dealing with a new project and I have to send data through headphone jack with specific voltage, then i can work on that voltage.

so here i need to progra

Answer 1

the simplest way to catch input data from audio jack in android or iphone is through recording http://developer.android.com/reference/android/media/AudioRecord.html

think something similar like playing a linear pcm audio file , I have n't tried but I believe it should work