If it is like my cellset (with a pushbutton?) When you switch the button it disconnects from BIKE COMMS. You can hear the ringtone BUT say if you are riding down the road listening to cb or mp3 player THEN you will not hear it only if you happen to be on the cellset side.
My cellset with the Thunderbolt android rings in the helmet. Some phones do and some dont, I think it is which phone you have. My boy has the same phone as you but he is not here or I would go pair it to the bike and check it for you.