Sashko

I've been working with a cheaper wireless backup camera with an external monitor, and I'd like to install a wired one that goes directly to my CSX' navi. From what I understand, I would need a video converter or what-not to do so. What is the most cost efficient solution that would work well to do so? I can see that they have some great cameras on eBay, but the converter or encoder part is the one that I seem to not be finding all that much info on here about.