Every thing in the shore power entry box (receptacle and plug) is 120VAC, and you can plug it in to shore power presuming you have camped on a shore with power.
For small amounts of 120VAC power, you can buy an inverter (changes 12VDC to 120VAC) and connect its input to either the truck or trailer battery
(at 12VDC) and connect its output (120VDC using a 15A outlet) to your shore power entry. If you have a 30A or 50A entry, you will need an adapter somewhere in that connection.
Please note I said SMALL amounts of power; we are talking lights
and little stuf like that, not heaters, coffee pots, a/c, microwave
, refrigerators, etc. Just about anything that produces heat is a heavy load.
Remember that the losses are greatest at the lower voltages, so the inverter should be as close to the battery powering it as possible; this is esp important if you want to power a color TV, because the degaussing load at startup is great enuf to drop normal cigarette lighter outlet wiring voltages below the inverter's threshold and it will shut itself off.
Back when I had a TV, and before I got an outlet to clip right onto the battery, I had to go out to the truck with TV and inverter, start the engine, rev it a little, and keep punching the inverter back on until enuf power leaked thru to charge the TV. Then I could take TV and inverter back into trailer, plug into cig lighter and watch it.
Pete and Rats