The electronic circuitry of the on-board monitor control panel (BMBT) collects information relating to key and rotary knob functions and makes it available on the I-bus.
During operation, light emitting diodes (LED) can be activated via I-bus data telegrams by the telephone, radio or by climate control electronics during independent heating.
The functions of the cassette drive are controlled by the on-board monitor control panel (BMBT).Activation of the cassette drive is triggered by I-bus commands from the radio.
The ambient brightness is measured by a phototransistor and, together with the information from the manual dimmer in the vehicle, the brightness of the LEDs and the button background lighting are controlled and a signal (PL signal) is produced for background lighting of the on-board monitor.
The on-board monitor control panel generates the operating voltages for keypad and cassette drive.