Hello , a few days ago I bought an Android radio for the w211 from AliExpress . After that I realized that I have the version with the optic fiber plug. So I messaged the send some pictures to the seller and he also send me a fiber optic adapter . After receiving both the radio and the adapter I still have no clue on how to connect this and the AliExpress seller doesn't really help . I have some experience with connecting car stereos but I never seen anything similar . Can anyone help me ?

There's plenty of threads on this in other forums. See this one might give you some leads

https://mbworld.org/forums/cls-coupe...ch-thread.html