the HS850 has a collapsable (sp) mouth piece, if its open the headset is on, if not its off. If you a wearing the earpiece (mp open / device on) it beeps when a call is coming in, it also beeps when your revieving a second call. You need to tell it to auto connect other wise you will need to approve the connection everytime you open the device, however once it is set to acccept the connection you can open the device once you phone rings and accept the call from the HS850, usefull if you dont like waering the device all the time.