Like Jimandchris said, just the signal from the antenna/cable TV service.
One other thing to mention - check the outside TV jack. On my 2015 IKSS, that jack is a smooth push-on style connector. All of the rest of the jacks in the camper and the inputs on the drivers side of the camper are screw on connectors. I had to buy a new push on style coax cable just for using with that one jack.
I live with fear every day, and sometimes she lets me go fishing.
2015 Shamrock 23IKSS
2008 Ford Expedition EL