The CM7001 is designed to receive over the air ATSC channels, and Clear QAM channels. Cable television operators typically have analog NTSC, Clear QAM, and encrypted QAM signals on their network. Many cable operators still carry all the basic channels as analog NTSC channels, and sometimes duplicate them as either Clear QAM or encrypted QAM channels. If the cable operator has upgraded its network to carry all digital signals, it is very common for them to only carry the limited basic channels (usually the local off air channels and the public, educational, and government channels) in Clear QAM, while the rest of the basic channels are carried on their networks as encrypted QAM channels.
The analog NTSC channels on a cable television network can be viewed by connecting the cable directly to the TV set. The encrypted QAM channels can only be viewed with the set top box provided by the cable operator. Check with your cable operator to see what channels are provided using Clear QAM.