Starting point: COMAND APS 50

If you switch from the COMAND APS 50 to a third-party radio, for example an Android radio, you have to consider how the speakers should be connected. The APS 50 in the front (head unit) is only a control unit, the actual functions of a radio are performed by the AGW (AudioGateWay) in the rear (trunk on the left side of the side wall). There are also the speaker connections.

There are two options:

Connection via Most adapter

An adapter to the fiber optic cable is required from the radio manufacturer; most Chinese radios offer this. The MOST adapter generates light signals from the audio output of the radio, which are then available to all participants connected to it via the MOST ring (Media Oriented Systems Transport). One participant in the MOST ring is the AGW in the rear. This reads the light signals and converts them back into electrical current that makes the speakers sound. 

  • Advantage: Easier installation, subwoofer still works because the original AGW is still used as an amplifier.
  • Disadvantage: fader function is lost (distribution of volume between front and rear).

Connection via speaker extension cable

A 5m extension cable is required from the radio manufacturer. Also offered by many China dealers, but must often be requested separately by message, as this is often not mentioned in the item description. Costs about 60€. With this, the speaker cables in the rear are extended forward to the Android radio.

  • Advantage: Fader function remains
  • Disadvantage: Cable must be laid. However, a cable has to be laid to the back for the GPS antenna, radio antenna and possibly microphone anyway. This can be done more or less elaborately. In principle, there are cable channels under the door sills and you have to work your way under the carpet to the gear lever, but you can also make it simple and lay the cables under the floor mats. Since power-supplying cables are also located in the door sill panels, you must ensure that the antenna cables are sufficiently spaced apart, otherwise reception interference can occur (despite shielded antenna cables).

An additional amplifier is optionally required for connecting the subwoofer. This is not absolutely necessary - the installed speakers of a Harman Kardon sound system, for example, offer enough reserves to feel the beats in your stomach without a subwoofer if necessary. However, if you want to get the most out of it, you will need an additional amplifier for the subwoofer. Either from the accessories section, or you can continue to use the AGW for this purpose:

Special case: AGW for operating the subwoofer

It is possible to run only the subwoofer through the AGW and run the other speakers directly to the Android radio to get the fader function. However, this requires a MOST adapter and 1m fiber optic cable in addition to the speaker extension cable. The MOST adapter is connected to the AGW exclusively via the fiber optic cable and via CAN cable. There is no connection with the rest of the CAN system or MOST ring of the vehicle! Both the MOST adapter and the extension cable for the other speakers are connected to the Android radio.

Removal of the CD changer

If there is a CD changer in the kinematics compartment, it is a good idea to remove it and sell it to save weight and gain storage space. If the MOST ring continues to be used (if the original radio is retained or a MOST adapter is used), it must be closed with a MOST bridge, because it is indeed a ring line and each participant has one input and one output. If you remove a participant (CD changer) and leave the MOST ring open, no data can be transmitted, the speakers remain mute.

Fixing the kinematic compartment

As soon as the AGW or the original radio is removed, the kinematic compartment no longer opens. The background to this is that, due to the potential presence of the CD changer, it must be ensured that no CD is in the movement space of the wooden panel and would damage the drive. This check fails as soon as one of the two components is no longer present. With a kinematics adapter from schlauHAUS, the kinematics compartment can be made viable again.

Afterwards, the space gained can be used again with a compartment insert. schlauHAUS offers illuminated compartment inserts here on request, because the original insert from the manufacturer offers only very limited space and no lighting.

Some vehicles of the model update (Mopf) do not have a kinematics compartment. In this case, however, the kinematics can be easily retrofitted. You can find more information here!

Setting the clock

With certain radios, the clock is set next to the speedometer via the original radio. Especially for those with navigation, the GPS time of the satellites is then used, and only the time zone can be set in 30-minute increments via the radio. Since this no longer works with a third-party radio, you now have to choose another way.

For this purpose, there is the menu item "Date/Time" in the speedometer display (KI), where you can set the synchronization with the head unit to "off". If this menu item is not available, it can be coded by a workshop with the SD.
After switching off the synchronization, you can set the time under this menu item using the odometer reset key.

4 thoughts on “W211 Zubehör-Radio anschließen

  1. Michael Hallmann says:

    Hello Mr Traxel,

    as usual from you, a comprehensive and competent answer. Many thanks for that!

    The kinematic adapter from their company has been working perfectly for half a year now, so I don't want to lose this function in a conversion.

    I want to convert the system because the Harman Kardon system sounds too bad with the simple adapter. This should work much better with a direct connection of the speakers.

    I think that I am already much further along with your advice. The colleague you recommended doesn't give away too much, as he prefers to do the conversions himself. He's just unfortunately much too far away.

    After my holiday, I will take the whole thing apart and check the inventory. If I manage the conversion, I will document it and publish it. At the moment, there are too few detailed descriptions on the subject, although in the end it is kind of plug and play.

    Many greetings
    Michael Hallmann

    P.S.: Which forum do you mean?

  2. dartrax says:

    Hello Mr Hallmann!

    Currently, as far as I can tell, everything is working for you - the compartment thanks to the kinematics adapter, all speakers via the FO (Fibre Optic, LWL) adapter. Now you want to connect the speakers directly to the radio and continue to operate the subwoofer via the AGW and an FO adapter?
    For this, the fibre optic adapter must have a cinch connection, CAN bus connection and, of course, the MOST connection. I was once recommended this one:

    The extension cable radio-speaker is correct. For the direct connection of the fibre optic adapter to the AGW, another short fibre optic cable is required. The fibre optic adapter moves to the rear of the AGW and is connected directly to the AGW with the fibre optic cable and CAN bus connection ("Method 2" in the linked article). In addition, the fibre optic adapter must be connected to the battery power and to the subwoofer output of the radio - so make sure that the speaker extension cable has enough connections.

    For further or up-to-date information on the subject, including advice on recommendable Android radio models, I would like to refer you to a specialist in this field, as my conversion was carried out several years ago now. He regularly converts customer vehicles in exactly this way. Maybe it's worth asking!

    I am curious about your experiences - gladly here or in the forum!

    With best regards
    Alexander Traxel

  3. Michael Hallmann says:

    Very informative article! At the moment I have an Android from Xtrons with a fibre optic adapter installed from the predecessor. Originally, a Japanese Comand NTG 1 was installed. I also have Harman Kardon with subwoofer and the ingenious kinematics adapter from you.

    What else do I need to be able to operate the secret compartment, bypass the AGW for the speakers and continue to operate the subwoofer via the AGW? Only an extension cable from the radio to the speakers or additional adapters etc.?

    Michael Hallmann

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