This is a small board that sits on the back of a CD-changed for Mercedes-Benz card which use the D2B fiber-optic protocol. The chip is labeled OCC8001-02.
The board has 2 external connectors: one electrical 3 pin (GND, 12V and “wake-up”) and one optical connector. There is internal FPC that goes to the CD-changer.
There is a similar board in the CD-changers used in Jaguar card, but they use different optical plug.