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.
Hierzu gibt es im Tacho-Display (KI) den Menüpunkt “Datum/Zeit”, darin kann man die Synchronisation mit der Headunit auf “aus” stellen. Sollte dieser Menüpunkt nicht vorhanden sein, kann er von einer Werkstatt mit der SD kodiert werden.
After switching off the synchronization, you can set the time under this menu item using the odometer reset key.