Managed to find some time in the sunshine yesterday and had a real play with the reversing camera gubbins.
I have purchased a Chinese (?) number plate light camera with three LEDs in it. I powered this with 12 volts from the Power Supply socket in the boot. The LEDs lit up.
I then connected the video out from the camera to AUX 1 on the analogue TV tuner. I landed up with a screen full of snow on the MMI just as if there was no video signal. (OK I'll look into that later.)
Then tried Aux 2. Wow!! Brilliant picture, and it had guide lines, they were not the Audi style bendy lines but a good guide none the less.
I had put Aux 1 & Aux 2 Kufatec cables in the TV tuner last year as my very first attempt at modifying the A8. Both inputs worked surprisingly well at the time using a cheap DVD player.
Next step was putting a transmitter on the camera video output and it's matching receiver on the Aux 2 input. Powered up and voila, still a very good picture, no apparent degradation via the Tx/Rx combo.
The idea here is to save me running a video cable from the boot lid to the main body of the car. I am still thinking that the X-CarLink might be a good way to go especially with the Tx/Rx kit. The LEDs in the camera wil be fed from the number plate light supply and the camera and Tx will be powered from the Reversing light supply.
Put it all away for another day
I now need an ignition hot in the boot, anyone know of a Terminal 15 in there? If I go with the X-CarLink then the Ignition hot will not be needed.
AND hoping that the camera will fit in the number plate light aperture. I know already that I will have to drill out the number plate light fixing screws and will do both because I have LEDs to fit in there.