OK
A modem will do zero good. don't waste your money.
The campground will either provide a modem (with deposit) or your connection is an ether-net connection.
Either option, you connect their modem (or cable) to a router, the router could be wireless.
From their point of view, you are consuming one IP, thus one connection.
From your point of view, you could connect as many devices as your router could support.
If they are providing the modem, that modem is registered into the system and the equipment on the other end knows that it can talk to it. If you tried to use your own modem, it would not be registered and the equipment on the other end would ignore it.
Some campgrounds that get their internet via their Cable-Co (eg Charter) have been going the provide a modem route. The problem they have been having is NOT getting the modem back from the campers.
