I have just purchased a 721 off ebay (after verifying from a Dish rep that the numbers on the receiver and card were good) - It arrived... they added it to my account and activated it. However the unit itself appears to be in a 'loop' and will not properly turn on - so I can't confirm if it works... Some dish reps say it is not going to work because of the old smart card - and that new cards will not function in it... But = they will activate it. -Brian