The King wifi is a repeater/wifi booster and that would be where the internal unit plugs into the rooftop antenna. Do you have a rooftop antenna for the booster? If so it sounds like the wires are there and you would just need the router. As far as the one control- that's a system that allows you to digitally control lots of things in your rv (jacks, pump, ac, lights etc) from a tablet like panel as well as through your phone. These 2 things are independent of one another. One is a wifi booster, the other is a control panel. What type of control panel do you have now? Personally I have a love hate relationship with my one control. So far it works fine but the touch screen is , well, touchy, and I always worry something will fail. Secondly- I got a new phone and cannot get the one control app to work on my new phone. Worked fine on my old phone.
