Send signals through a headphone cable

Question

I worked a bit on this, but found nothing.

I have an idea for a device management application that will need to be connected via a headphone cable.

Can I send signals through the headphone jack?

Answer 1

Arbitrary data can be reproduced through an audio cable using Media Playerwith the source resource. The signal will be limited by the bandwidth of a particular device, for example, from 20 Hz to 16 kHz.

Answer 2

use AudioManager

AudioManager audioManager = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);

http://developer.android.com/reference/android/media/AudioManager.html

WiredHeadsetOn (true) setMode