Hi there, Anybody know 'what the deal' is with installing a cable card into a Roamio OTA unit? I never quite understood how, or what, actually distinguishes these units from one another. They both have the card slot / compartment. So why is one sold as "OTA" unit, and the other one is either / or? Are they running different software? Is the CC compartment in the OTA unit disconnected? Thanks for any insight.