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

GF82.85-P-0003TA Cockpit Management And Data System (COMAND), Function
- with CODE (527) COMAND APS (with navigation)

Component Identification:

Function
The COMAND operating, display and control unit (A40/3) is the central operating unit for the entertainment and communications systems integrated into the vehicle within the MOST ring. All participating system components and control units can be selected and operated via the COMAND operating, display and control unit (A40/3) and in addition, provided this is included in the package, with the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111). The COMAND operating, display and control unit (A40/3) has a video-compatible LCD color display. It is used to output information such as operating menu, map data for navigation and video image. The COMAND operating, display and control unit (A40/3) can be operated using the three main control fields, which are located on the left and right of the screen and below it, a cross-shaped rocker button (cursor, enter) and a rotary switch (volume, ON/OFF).

Controls for the COMAND are:
^ permanently programmed function keys
^ alphanumeric key block
^ programmable function keys
^ Rotary switch with integral ON button
^ Direction input element with OK button
^ Voice repeat button for navigation
^ mute button
^ Remote control

Part of the controls are assigned with fixed functions, i.e. irrespective of the screen applied in each case they always trigger the same response. Some functions can be activated using the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111). However these button operations are first processed by the instrument cluster (A1).

The instrument cluster (A1) links the incoming keypresses to the current menu setting on the multifunction display (A1p13). If necessary, it sends a corresponding CAN message via the audio gateway control unit (N93/1) to the COMAND operating, display and control unit (A40/3).

The following functions can be operated centrally:
^ Radio mode
^ CD player mode
^ Navigation mode
^ RDS/TMC (dynamic navigation system, Germany)
^ telematics (telephone, SMS, WAP)
^ Voice control
^ TV mode
^ External audio devices via AUX connection

Participating system components of the COMAND operating, display and control unit (A40/3) with full equipment:
^ Audio gateway control unit (N93/1) (contains radio receiver, CAN B interface, MOST interface, radio amplifier and audio processor)
^ Telecommunications control unit (N112) (telephone, short message service, WAP, emergency call, traffic services) or telephone interface (A34/4)
^ Navigation processor (N41/1)
^ Voice control system control unit (A35/11)
^ TV tuner (A2/10)
^ CD changer (A2/6)
^ Multifunction steering wheel
^ Instrument cluster (A1)
^ Operating and display unit display in rear (A40/2)

As an option, the vehicle can be equipped with an infrared remote control for operating from the rear compartment and with code (813) voice control system (VCS) for the telephone/audio functions. This increases the operator convenience.

MOST bus system
The digital components in the COMAND operating, display and control unit (A40/3) are interlinked through the MOST ring. The data (control commands and useful information) are transmitted between the different system components via the bus system. This includes control data and audio signals (music from CD player, voice when making a call).
Because some of the individual components work with different data formats or require different data transfer rates and security levels, different bus systems have been installed:

Bus systems:
^ Media Oriented System Transport (MOST)
^ CAN interior (CAN B)
^ CAN engine compartment (CAN-C)

Via the MOST ring, data/signals are exchanged between the audio gateway control unit (N93/1), the COMAND operating, display and control unit (A40/3), CD changer (A2/6), telecommunications control unit (N112) and the voice control system control unit (A35/11).
In the process both control data and the actual audio signals are transmitted (music from CD changer, voice when phoning). The COMAND operating, display and control unit (A40/3) communicates with the audio gateway (N93/1) and other system components via the integrated MOST ring interface.

Interfaces
The CAN interior (CAN-B) is used for data exchange with the instrument cluster (A1).

This is how the instrument cluster (A1) receives the audio, telephone, and navigation data for the multifunction display (A1p13) in the instrument cluster (A1) and the time from the COMAND operating, display and control unit (A40/3) via the audio gateway control unit (N93/1) using this bus.
Time synchronization between the COMAND operating, display and control unit (A40/3) and the instrument cluster (A1) can also be performed via the multifunction steering wheel.

In order to obtain data (for example, for dead reckoning) for position finding, the CAN engine compartment (CAN-C) is linked to the CAN interior (CAN-B) via the central gateway control unit (N93).
The data read in by the ESP control unit (N47-5) are placed on the engine compartment CAN (CAN-C). Here they are available via the central gateway control unit (N93) interface on the CAN interior (CAN-B). The navigation processor (N41/1) can access these data via the MOST ring using the audio gateway control unit interface (N93/1).