I have Bluetooth embedded in my car its default mediasystem. When my phone (Nexus 4) is connected it displays the signalstrength and batterylevel of the phone on the display. What Bluetooth profile/protocol is used for this? I've investigated the HFP and MAP profiles but couldn't find anything on signalstrength or batterylevel.
In the end I want to make an Android app which sends the batterylevel to the car its Bluetooth 'carkit' to enable a charging 'animation'.