Echo Issue with Android Auto/Bluetooth

Why Carplay without Echo

-When you using the Carplay System, the Bluetooth System automatic disconnect between the phone and the Radio Device. So the radio purely accept the Microphone from the Carplay Radio System only.

Why Bluetooth and Android Auto with Echo

-When your phone running with Android Auto System, you need to connect with bluetooth for the Microphone. And if your radio system was RNS510/RCD310/RCD510 with bluetooth Module, even you change the radio system, the Microphone still there, when you are making call, you are using two microphone at the same time, this is the main issue to have the echo.