Took the second Multi stream cablecard from the Series 3 and put it in the XL4. I was getting ready to call Comcast to get the card paired when I went to the XL4 and found all the channels active. Not just the over the air ABC, NBC, etc, but other HD channels on the extended tier. We have no pay channels like HBO or Showtime. Everything available on the Series 3 is available on the XL4 with out contacting Comcast. I also have access to Xfininty on demand. Any guesses on who this is working?