1. When both connected devices are idle:
1) The headphones will output audio from the device that receives or makes a call.
2) If one device starts playing music first, its audio will be played through the headphones.
2. When only one device is playing music:
1) If the non-playing device receives or makes a call, the current music will be muted (not paused) and call audio will be played. After the call ends, music playback resumes.
2) If the non-playing device starts music playback, there will be no audio switch. Both devices will continue playing, but the later device will remain muted.