Music 
Play/Pause: Press MFB 
Volume Down/Up: Press -/+ 
Previous/Next Track: Long press -/+ 

Calls 
Answer/end call: Press MFB 
Reject a call Long: Press MFB 
Mute during call: Double press - 
Re-dial last call: Double press MFB 

Call waiting
Receiving call and reject on going call: Press MFB 
Receiving call and hold on going call Long: Press MFB