"dial home" is just slang, the technical term is Reverse Tunneling. Basically a firewall (in most cases but not all) is a one way door. It lets you out ie from the campground out to surf, but it prevents all the hackers of the world from going in to access your stuff. The only way around this is for their IT guy to make a rule that basically says allow outside (internet) to inside (campground) to my camera on http port (web access). The way around the complexity of this is for the Camera to "phone home". The camera will boot up and connect to their company website. This connection is like a tunnel out from the camera to the website. Now when you access their website and connect to your camera you "reverse tunnel"... travel backwards down the tunnel back to your camera inside the campground.
