The Bluetooth control unit M161 receives a direct power supply - pin 11 of connector A - from the battery via the line for fuse F39 of the junction unit under the dashboard. It receives an ignition-controlled power supply (INT) - pin 1 - via the line for fuse F49 of junction unit B2 .Pin 10 of connector A of the Bluetooth control unit M161 is earthed. Pins 17 and 18 of connector A of M161 are connected to the microphone P26. Pin 7 of connector A of M161 sends the MUTe signal to the radio P20 - pin 9 of connector C, whilst pins 9 and 16 of connector A of M161 send the control signals for the speakers to the radio P20 - pins 7 and 8 of connector C..The other signals are exchanged with the switch H118 and in particular at pin 5 of connector A of M161 the "End Key" signal arrives, at pin 3 of connector B of H161 the "Send Key" signal arrives and pins 17 and 18 of connector B of M161 send the lighting and earth signals for the control panel H161.