A few years ago I picked up this machine with the genlock and a 10-pin screw-on DIN socket on the back. After a lot of brain racking and searching the internet to find nothing I finally braved the task this weekend to play around with it.

I got the Genlock working with the BBC Master overlaying a TV picture. But that doesn't appear to be everything that was originally working with it....

There is a ROM named 'VideoROM 3.1' in one of the ROM expansion sockets which appears to control an external unit through the user port. There also is a couple of fly wires from IC6 - the 6522 chip to the 10 pin DIN socket.

What does the 6522 chip on IC6 do?

Has anyone ever heard of such a setup with the videoROM and cox 630b genlock?