Microphone issues on hands free

[Bozman]

Ayup guys, I’ve got a 2007 e320 w211. My problem is if I connect my phone to Bluetooth dongle via Aux I can hear calls and callers can hear me. But if I connect through the Bluetooth on head unit I can hear callers but they can’t hear me. Any help would be very much appreciated.

 

[Blobcat]

My '07 spec W211 required a Bluetooth adapter in the central armrest for the phone to work with the Comand unit. What is your head unit? Comand or Audio 20 or something else?