I am using the optical cable. I am using the same kind of cable to connect the Dish receiver as well. Except it works for the Dish receiver.
Do you have to switch cables?
Also for high end video, you should use the RGB (red, green, blue DVD type) digital cables or at the very least an S-Video cable. Don't use the yellow RCA cable or the RG-6 (cablevision type) for a high-end signal.