You can use the inline remote control buttons to do the following:
During a phone call
+/- button — Adjust in-call volume
Multifunction button — Answer an incoming call and end an existing call
While listening to media/music
+/- button — Adjust the volume
Multifunction button — Play/Pause (one click), play the next track (double-click), play previous track (triple-click), activate Voice Control for Apple iOS devices (click and hold).
NOTE: Inline remote control button functions may vary by device.