I wish I could see the boxes that Comcast gives you. I wasn't able to find any technical info on them. Tivo has, I believe, 3 types of serial connections that will work, but it wouldn't suprise me if Comcast is trying to push their own technology. They're big on their "On Demand" service, which sounds really cool in theory, but I have a friend with the service, and he says it only works about 25% of the time.