Hi there
If you have sat nav plus 5.6 inch screen with out TV function you can use a lead which plugs into the din plug on the rear of the unit. very simple to fit and works well.
Once the adaptor is fitted in the radio/cd/tv button works all functions. No coding required just plug and play
I had 6 disc DVD changer, Playstation 2, Reverse camera all running through my screen no probs.
I got the lead now going spare they are about £80 new from memory.