AB Shutter 3 is a small remote shutter.

It connects to your handset as a Bluetooth keyboard. But which key codes does it send to the device?

To answer this question, I simply connected the shutter to my Android device, started an editor and pressed the buttons.

These are the results:

Key function
Volume Up
Enter + Volume Up

Be aware: it is possible, that there are some other key codes sent that went unnoticed.