The AC generator will power all of your AC appliances when the RV is not plugged into a power grid at a campground. The AC generator is not an efficient energy source as it works best when under heavy electricity loads, such as for powering air conditioners. The generator is expensive and very noisy to run and not recommended when you need to power AC appliances that do not need a lot of electricity. This is typically used when no power source is available at a campground. The AC generator is prone to power outages and surges which can damage appliances.
The AC power cord is used to plug the RV into the power source at a campground. Your RV can have a 30 amp cord or 50 amp cord. The 50 amp cord will have a four prong plug. This AC system provides enough power so you can run all of your AC appliances at the same time. A 30 amp system will have a three prong plug. While this system provides a bit of power you may not be able to run all of your appliances at one time. It will take some trial and error to determine how many appliances you can have on before tripping the circuit breaker.
A UPS system is best for powering computers and other sensitive electronics in the RV. UPS stands for uninterruptible power supply system. This is an AC system that plugs into the RV's main AC power supply. It contains an internal battery so if the AC power supply should shut off the computer will maintain constant power. Fluctuating power can cause the battery to drain and surges can damage the hardware. A constant unchanging AC power source is important for all computers and computer accessories.
Have some AC plug adapters on hand. Not all campgrounds will offer different AC power plugs. Therefore you will need an adapter to plug in a 50 amp system into a 30 amp socket, and vice versa. This way you can feel secure that you can plug your RV into any campground no matter the AC power source.
A surge protectors is important to protect your appliances from power surges. This will prevent damage from voltage highs and lows, surges, bad wiring at campgrounds and other electrical issues. Many RV owners have had to spend a lot of money because of damage due to bad wiring at campgrounds. Plugging the AC cord into a surge protector and then plugging this into the campground pedestal will protect your RV. The surge protector will analyze the power supply and let the AC power through if the voltage is correct. It will block the electricity if something is the matter with the AC power.
If your RV contains AC appliances but no AC generator then you will need an inverter to convert the power form the DC batteries into AC power. This is used when there is no AC power source available at the campground. Most high end RV's will contain an inverter but the tow-able RVs will not. If you do not have an AC generator then it is a good idea to have an inverter on hand.