Can someone elaborate on this option?

"OEM CD changer control (connection via AV-IN, CD change possible via buttons 1-6) requires adjustment of the cabling"

I have had the avin avant 4 + ibus app on my zhp for a year or so now and wasn't aware of this option. Are there instructions or anything on how to get that working?

I'm not really going to use it but Im one of those people that likes OEM ish options. I'm trying to procure as many as i can so I was pretty upset about not having it work. But now i'm seeig maybe it will work.

Thoughts? Anyone tried it? I didn't see any info on the installation PDF

https://download.speedy-pics.de/uplo..._interface.pdf