Ours has two "combo" coax/HDMI receptacles... one in a cabinet above the entry door (to which the over-cab TV is connected), and another in the bedroom TV area. The coach exterior coax connector is wired to the two interior coax connectors in those receptacles.
In the cabinet above the entry door, there is a small "HDMI distribution box" with one HDMI input, and four HDMI outputs - two of which are wired to the aforementioned combo receptacles.
The idea is to plug in a DVD player or Fire stick - or any HDMI video source - into the distribution box input. That video signal will then be fed to the other two TV HDMI receptacles. So by switching the "video source" in the TV's settings, you get either coax-fed or HDMI-fed video.
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