Cockpit management and data system (COMAND), function - GF82.85-P-0003RM

MODEL 230.467 /474 /475 as of 1.6.04 with CODE (527) COMAND APS (with navigation) 

MODEL 230.476 as of 1.6.04 

Fig 1: Cockpit Management And Data System - Communication Diagram

The COMAND operating, display and controller unit (A40/3) can be used to operate the following systems centrally:

• Integrated radio tuner
• Integrated digital versatile disk (DVD) drive for playing navigation or audio CDs, video DVDs and MP3s
• Navigation system with dynamic destination-oriented navigation system
• with code (388) Universal Portable CTEL Interface System
• with CODE (810) Sound system
• With code (813) Voice control system (VCS)
• With code (819) 6-disk CD changer
• With code (860) TV tuner

The "Audio-AUX" function enables additional audio sources such as, e.g. an MP3 player to be integrated into the front entertainment system. An AUX jack is located in the glove compartment as a connection facility.

The COMAND operating, display and controller unit (A40/3) is the central component of the COMAND system. It has a color liquid crystal display (LCD) with video capability for displaying information such as operating menus and map data for navigation. It is operated using fixed function keys and 2 rotary switches as well as assisted by menus on the display of the COMAND operating, display and controller unit (A40/3). Some functions can also be activated with the aid of the pushbuttons on the multifunction steering wheel (MFL). It should be noted that all button actuations on the multifunction steering wheel (MFL) are processed by the instrument cluster (A1) first. The instrument cluster (A1) combines the incoming button actuations with the current menu setting on the left multifunction display (A1p13) and, if necessary it sends an appropriate Controller Area Network (data bus/CAN bus) (CAN) message to the COMAND operating, display and controller unit (A40/3).

COMAND data bus system 

The digital components in the COMAND operating, display and controller unit (A40/3) are interlinked through a data bus system. The databus system is used to transmit data (control commands and useful information) between the various system components. The individual COMAND data bus system components operate with various data formats and they have different requirements in terms of transmission rate and reliability. Therefore, the following different data bus systems are installed:

• Media Oriented System Transport (MOST)

  Data between the MOST components are exchanged via the MOST. Both control data as well as the audio signals are transmitted.

• Controller area network bus class B (interior compartment) (CAN B)

  Data is exchanged over CAN-B between the COMAND operating, display and controller unit (A40/3) and the instrument cluster (A1). Here the audio gateway control unit (N93/1) is the interface between CAN-B and MOST. These data bus systems are used by the instrument cluster (A1) to receive the audio, telephone and navigation data as well as the time from the COMAND operating, display and controller unit (A40/3) for the left multifunction display (A1p13) in the instrument cluster (A1).