I spent some time looking at the TV configuration in my 340 and I have a couple of questions. First, I can only find that the current TV unit runs on AC power. In addition I cannot get the unit to turn on unless connected to shore power or generator. The only cord (besides cable) to theTV is the standard electrical cord and nothing else, and I am assuming if the unit was connected to 12V there would be some other wire to the unit..is that correct? If in fact this is the case does anyone know if this was the standard TV configuration on this model/year?
Second....I can't seem to locate a cable input so I have been investigating how to get cable inot the boat. When looking around the salon I fould a black box up on the very top of the cabinets in the galley with two sets of cable running into it

, and one cable running out to the TV. It also has a switch that when flipped turns on/off a red LED on the black box? Why two sets of cable running into the box and what the heck does this thing do?
Thanks so much for the help!!!
Best,
kurt