Emulating Kenwood's cd changer

[Miss-Electro]

Hi all, I am starting a project involving the emulation of a cd changer, it will permit to play mp3 files (but also midi, mods, and any other audio file...) from a storage source (flashdisk, hard drive, internet radio...) and pilot all functions via the head unit.
For now I think to use a PIC for the interface with the head unit via the DIN 13 connector on it's back.
Audio playing will be imlemented on a raspberry pi, maybe in future also the interface part will be assigned to raspberry, thus permitting to eliminate the PIC part.

The first problem I have is about the Kenwood's protocol, the specifications have not been released by Kenwood and the only information I have found is on sites like this:
http://www.adriangame.co.uk/kenw-dc-pro.html

So, I'm asking if someone is able to send me some more information or other sources of information about Kenwood's interface protocol.

Time to receive the DIN 13 male connector ordered on ebay and i'll start to try to talk to the headunit...

Thanks.

[hacsx]

I would suggest getting your hand on the CDC itself.
Build a logger unit and software for it.  Not just rely on the website.
I know that order of message matter in some cases.
Good luck.

[solutions]

Why don't you emulate the head unit USER INTERFACE (if you must...) instead of wasting your time emulating someone else's obsolete mess? You can do a lot these days with touchscreen LCDs that Kenwood couldn't a decade ago. I'd do my own programmable controls - that way the screen changes depending on what media you want to access.

Run CAT5 ethernet cable out to the trunk and use a raspberry at each end.

[hacsx]

From previous experience getting the command is one thing but implementing it in the right sequence as what the head unit want is another.
You will need to figure out command is sent out first or what command is use in response to what command.
I have work with various protocol and they all are different.  

Also in cd changer you might not be able to change text at will.  You would need to trick the head unit into thinking that a disc change to get TOC text.