The standard for video output on 8-bit computers is there was no standard. Well, oddly enough, a bunch of companies did something super similar, but there are enough gotchas that you have to be careful. At least Atari sidestepped the problem. Here’s my experience with Atari 800 video cables, which also (mostly) applies the XL and XE variants. And you can use the same cable with other machines in a pinch.
Atari 800 video cables









