Help with using the RF input/output on DM box

Instead of using the cable company's digital receiver I'm using my DM7020. I don't have the satellite YET for these channels so am running the RF cable into the DM's RF in and then RF out to my TV. BUT I'm only getting the analogue channels though :06:- none of the digital channels are being scanned. My peers confirm my local is working so all channels should be clearing (as the TV has a digital tuner). Any pointers on how to get all channels to show on my TV (without setting up the satellite).

Makes sense. But what are the RF in/out connections for? And whats weird is I'm getting the analogue channels through.