This app will help you test your headset/headphones.
- With this app you can easily determine if headset (TRRS 4 pin) or headphones are connected to audio jack. Some Android devices do not show you this information (for example, Samsung S4).
- App can be used to make electrical tests. If you want to assemble your own remote control, you can test how device will recognise different values of resistance.
Tips:
- While plugging, no one button should be pressed on remote controller, otherwise device will not recognise mic.
- I have never seen 4-function wired headset, but in google specifcation there is reserved "voice" function. I tested it with command "adb shell input keyevent KEYCODE_VOICE_ASSIST". It was introdused only since Android 5.0 as keycode 231. On 4.4.2 this keycode was used by samsung as KEYCODE_EMAIL.
- This app only will show you generic headset buttons. If you somehow modified kl files in /system/usr/keylayout, then you should better use KeyTest app.
https://play.google.com/store/apps/details?id=ru.linuxcomp.apps.hstester