It is 50 amps at 120/240 volt, Same exactly (Save for the amprage) as your house.
You have a 4 wire plug, the "Odd" pin is safety ground, we will ignore that for this presentation
The other 3 are L-1, Neutral and L-2 L to Neutral is 120 volt, L1-L2 is 240.
NOTHING in your RV should need 240 volts unless you have an Energery Management System, which uses the 240 volt to detect "50 amp service"
If you are hooking to a 30 amp park via a dobbone, Do not worry about it the dog takes care of it.
By the way, for 30 amp users (3-wire 120 volt) using a dogbone to hook to a 50 amp site.. Same thing, the dog takes care of it.