Logic does not always apply, especially when RV manufacturers label things.
The CABLE connector on the outside of the RV NORMALLY goes to the splitter/amplifier and is designed for cable TV input that does not require a digital box, it is for cable systems that connect directly to the TV so you scan for the channels.
The SAT/AUX port should be a direct COAX from the storage bay to the panel behind the TV it is designed to be used with a receiver box system such as you ran into or for the satellite receiver to connect through to the dish.
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