Just received a Beotooth 5500 today. I was able to modify the DIN7 by cutting the Datalink wire and then heating the two extra pins with a soldering iron and pulling them out once the plastic slightly melted.
Plugged into my Beomaster 2400 with S75 speakers (both just restored with new caps and other failed parts). Sounds great!
So glad to be able to play something other than the radio 🙂
The sound quality seems crisp and clear.
Thanks @pilatomic!
Going to restore the turntable next…