Hello, I have the Hama Bluetooth audio transmitter/receiver plugged into the AUX of my car radio (VW California T5) with which I connect an Apple Iphone 12 via Bluetooth. Music from e.g. Spotify, Google Maps instructions run perfectly and the sound/instructions come through on the car's speaker system. Unfortunately, I can't get a call (sound only) to come through on the car's speaker system as well. Has anyone had the same problem or a tip on how to get the sound onto the car's PA system as well? Before I got the Hama Bluetooth audio transmitter/receiver, I connected the iPhone directly to AUX with a transition plug (without Bluetooth), and this also worked so that the sound came through to the car's loudspeaker system. I am grateful for any tips