GF82.85-P-0003TMJ Cockpit Management and Data System (COMAND), Function

GF82.85-P-0003TMJ Cockpit Management And Data System (COMAND), Function
- with CODE (498) Japan version

Component Identification:

The COMAND operating, display and controller unit (A40/3A40) can be used to operate the following systems centrally:
^ Radio tuner in the audio gateway control unit (N93/1)
^ Integrated digital versatile disk (DVD) ROM driver
^ Integrated Minidisc (MD) drive
^ Dynamic destination-oriented navigation system via external Vehicle Information and Communication System (VICS)
^ CD changer (A2/6A2)
^ Personal Digital Cellular (PDC) mobile telephone
^ Sound system (model 219.35 with code (810) Sound system)
^ Voice control system (VCS [SBS])

The COMAND operating, display and controller unit is the central component in the COMAND system. It has a color liquid crystal display (LCD) with video capability for displaying information such as operating menus, map data for navigation, TV media and video media. It is operated by means of preset function keys and two rotary switches as well as menu-assisted on the display.

Some functions can also be activated with the aid of the pushbuttons on the multifunction steering wheel (MFL). It should be remembered in this case that all button operations on the MFL are first processed by the instrument cluster. The instrument cluster links the incoming button actuations with the current menu configuration on the multifunction display (A1p13) and, where applicable, it sends a corresponding Controller Area Network (data bus/CAN bus) (CAN) message to the COMAND operating, display and controller unit.

COMAND data bus system
The digital components of the COMAND operating, display and controller unit are networked with each other via a data bus system. This data bus system is used to transmit data (control commands and useful information) between the various system components. The individual components operate with different data formats and have different requirements on transfer rate and safety. Thus, different data bus systems are installed.

The COMAND data bus system includes the following:
^ Media Oriented System Transport (MOST)
Data between the MOST components are sent via the MOST bus. Both control data as well as the audio signals are transmitted.

^ Controller area network bus class B (interior compartment) (CAN B)
Data exchange takes place via the CAN-B between the COMAND operating, display and controller unit and the instrument cluster. Here the audio gateway control unit is the interface between CAN-B and MOST. These data bus systems are used by the instrument cluster to receive the audio, telephone and navigation data from the COMAND operating, display and controller unit for the multifunction display in the instrument cluster along with the time.

The "Audio AUX" function in combination with the AUX jack in the glove compartment can be used to connect additional audio sources (e.g. MP3 player, Walkman).

Data exchange between COMAND operating, display and controller unit and instrument cluster
The following systems controlled by the COMAND operating, display and controller unit can be operated with the aid of the buttons on the MFL and the multifunction display of the instrument cluster, and information on the systems can be called up:
^ Audio systems (e.g. radio tuner in audio gateway control unit, CD changer, etc.)
^ Navigation system
^ Telephone system

All data are exchanged between the instrument cluster and the COMAND operating, display and controller unit via the CAN-B and MOST. All button actuations on the MFL are received by the steering column module (N80) as an interface between the local interconnect network (LIN) bus and the CAN-B. The steering column module transfers the data on the CAN-B. The instrument cluster receives the data and links them to the system currently displayed on the multifunction display.

This interpretation is necessary, as the function of the buttons is dependent on the current content of the multifunction display. The interpreted data are sent from the instrument cluster to CAN-B, forwarded to the audio gateway control unit and received from the COMAND operating, display and controller unit via the MOST.

A change of system on the multifunction display has no effect on what appears on the display of the COMAND operating, display and controller unit, but the change in the display on the LCD color display of the COMAND operating, display and controller unit will affect the multifunction display.

The instrument cluster receives the current time from the COMAND operating, display and controller unit, since this is received automatically via the global positioning system (GPS).