The factory Volkswagen backup camera has RGB video signal but the aftermarket head units only accept CVBS video signal. So when you replace the factory VW head unit with an aftermarket head unit, you may find that the original camera video does not show on the aftermarket radio's screen because the video format do not match. Then you need this item.
For VW, Skoda, Seat cars, this RGB To RCA Decoder (Converter/Adapter) Box is designed for you to Maintain the OEM reverse camera function when fitting an aftermarket head unit/car stereo. It transforms RGB video signal into the CVBS (Composite Video Broadcast Signal). Fits OEM cameras that are connected to RCD510, RNS510 and RNS315 head units.

If your aftermarket Car Stereo supports dynamic trajectory, just buy this Decoder box to keep this function. In fact, dynamic trajectory is one of the functions from the Car Stereo, not from the reverse camera.
Please note below:
1. Your original car rear view camera must be RGB Video format.
2. This item must be used on aftermarket car stereo, not original VW radio.
3. Only For VW Volkswagen Vehicles Fitted with head units of RNS510 (MFD3), RNS315, Columbus or RCD510 (RCD510 with 26 Pin Connector Only).

Wiring diagram