Check with Comcast for the output specs on the box but it will be either DVI or HDMI. The SXRD is HDMI so you will either need a DVI/HDMI cable or just a straight HDMI cable. If the Comcast box is DVI you will need RCA audio cables.

Does Comcast offer a cable card in your area? If so then you won't need any cables unless you're setting up a HT as well. If you're hooking in a HT system then all of the cabling might be a little more complicated.

__________________
Wake up every day that would be a start.