Becker Navigation: Steering Wheel Remote Protocol

I'm currently developing my own CAN bus interface for my car, with all sorts of extra features that standard interfaces can't offer.
Now, I would also like to comfortably integrate a Becker navigation system.
Unfortunately, there is no specification (bus system, protocol) on how to remotely control Becker devices. Becker refuses to provide any information on this matter .
'Does anyone have any idea which protocol Becker (on the mini-ISO) uses? It seems to be a 2-wire interface, possibly I2C?'

If the prototype is ready, will the design also be released for reproduction, if...

btw: a big thank you again to Fuchs for his interface! It provides good service for initial attempts and for the 'dry run' }.

Hello TIK,

Have you ever looked at Michael's (http://www.mictronics.de) 'Becker Unilink' page?

Best regards,
Stefan.

hello stefan,

No, I wasn't familiar with that website yet, thank you very much!
It seems that the TXD/RXD pins are indeed part of an RS232 interface.
That would be simple, let's see .