I work for a cable access station and we currently have an AG-MX70 switcher and a Compix GenCG graphics computer. We have it hooked up downstream of the switcher currently, but I want to move it upstream so the director can have ultimate control of the graphics. I noticed that the switcher has a key input and the Compix has a key output, put looking in the manual things get pretty confusing. It talks a lot about EXT, DSK, and ME. While I think I know that they stand for, I'm not exactly sure what they mean/do, so basically I'm stuck.