The SAT4D System Allows you to Monitor Anything, Anywhere, and know where it is.Watching over a remote site can be a challenge when the location is very remote. The New Sensaphone SAT4D is designed to monitor remote sites no matter where they are located. Instead of relying on phone lines or cell phone services which are not always available, the SAT4D uses direct satellite communications. The result is 100% communication coverage across the United States as well as many other countries, too. No need to worry about cell phone coverage maps, which carriers are in the area, or analog vs. digital support. It works everywhere, plain and simple.