I have one of those special cables that lets you play Progressive scan compatible games on a VGA monitor in high quality. It is good, but it won't work on non-progressive games, nor at the GC's boot up screen and menu. So for those things, I have a cruddy converter box. It's a pain to constantly have to switch cables, so I want to make a circuit to automate this. If there is a signal coming from the progressive scan cable, then it would connect it to the monitor. Otherwise, it would connect the converter box to the monitor. Here's a picture to show what I mean:
Any suggestions on how I could do this?