The DVR+(CM7500) has 2 internal tuners. This allows you to record one program using one tuner, and simultaneously watch or record other programs using the second tuner. If recording 2 programs and you try to change to a third channel is not possible without cancelling one of the recordings already running.
CM-7500TB1 CM-7500GB16 CM7500GB16 CM7500TB1 CM-7500 CM7500