Media interface function

Function requirements for media interface, general

 Circuit 30g ON

Media interface, general

The Media Interface function is also known as the "Universal Consumer Electronic Interface" or as the universal equipment connecting point. The media interface allows the following portable terminals to be connected to the audio equipment through an adapter cable, the media interface electrical connector (X18/70), the media interface control unit (N125/1) and the Media Oriented System Transport (MOST):

- AUX devices (class 1)

- iPod or serial universal serial bus (USB) devices (Media Transfer Protocol (MTP)) (class 2)

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AUX devices without an operating facility are connected to the AUX connection.

iPods can be connected to the iPod connector.

MTP devices are connected to the USB connector and the AUX connector.

 If an attempt is made to connect a USB memory stick top the adapter cable, the Audio/COMAND display (A40/8) shows a "Note: Please connect device to another USB port". The USB electrical connection (X115) for connecting USB memory sticks is located in the stowage compartment (telephone compartment) under the center armrest.

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 With the "AUX" audio source, "Standard" and "Boost" can be selected in the "Volume" menu. The input level can be increased by selecting "Boost".

 The AUX electrical connector (X39/45) in the stowage compartment (telephone compartment) under the center armrest is no longer applicable.

 The portable devices listed are controlled using one of the following controls:

- Buttons at audio unit

- Audio/COMAND control panel (A40/9)

- Left multifunction steering wheel button group (S110) and right multifunction steering wheel button group (S111)

- Voice control system (VCS [SBS])

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Function sequence for media interface

The media interface control unit is supplied with voltage via two direct lines (circuit 31 and circuit 30). If a portable device is connected, it is recognized by the media interface control unit via the following route:

- Adapter cable

- Media interface electrical connector

 Not all portable devices can be recognized by the media interface control unit (AUX devices, for example, are generally not recognized).

The Media interface control unit then sends a signal to the audio equipment, which, in the case of iPods or MTP devices (however, not for AUX devices), enables them to change to the connected source.

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 Menu navigation and graphic representation of the menu navigation are accomplished on the Audio/COMAND display and are dependent on the specific portable terminal connected.

The user can now display the audio data or video data on the Audio/COMAND display by selecting the "Media Interface" menu item as well as the specific submenu item ("Normal Track Sequence", "Track List Mix", "Medium Mix").

The "Media interface" menu item and the specific submenu item can be selected using one of the following controls:

- Buttons on audio unit

- Audio/COMAND control panel

- Left multifunction steering wheel button group and right multifunction steering wheel button group

The control signals from the buttons on the "Audio equipment" are processed internally.

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The control signals of the multifunction steering wheel button groups are forwarded to the "audio unit" via the following route:

- Direct line

- Steering wheel electronics (N135)

- Steering LIN (LIN E1)

- Steering column tube module control unit (N80)

- Chassis CAN (CAN E)

- Instrument cluster (A1)

- Interior CAN (CAN B)

The control signals of the Audio/COMAND control panel are read in by the audio equipment over the telematics CAN (CAN A).

Following evaluation of the control signals in the audio unit, they are forwarded by the audio unit to the connected portable end device via the following route:

- MOST

- Media interface control unit

- Media interface electrical connector

- Adapter cable

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The connected portable terminal evaluates the control signals and sends the corresponding audio signals and data to the audio equipment via the reverse route.

On vehicles without code (810) Sound system, the audio equipment emits the audio signals over the speaker system via direct lines.

For vehicles with code (810) Sound system the voice output is sent over the Media Oriented System Transport (MOST), then amplified in the sound system amplifier control unit (N40/3) and forwarded over direct lines to the speaker system.

 More detailed information on the speaker system is available in the "Speaker output function" document.

Video signals and data are transmitted over a coaxial cable to the audio unit. The audio unit then processes the video signals and data internally, and forwards them over a low voltage differential signal (LVDS) line to the Audio/COMAND display. This is possible with the following equipment variants:

- With code (512) COMAND APS with DVD changer

- With code (526) COMAND with single DVD drive (without navigation)

- With code (527) COMAND APS with single DVD drive (with navigation system)