US Patent 7317927 Method and system to monitor persons utilizing wireless media

A method and system of selectively communicating with a first portable device within pre-defined geographical zones is disclosed. The first portable device is associated with a geographical zone defined utilizing latitude and longitude attributes. Data representative of the geographical zone is then loaded on the first portable device. The first portable device includes a ground positioning unit receiver which allows the first portable device to receive positioning data and to determine its position in relation to the geographical zone. When the first portable device determines it is within the geographical zone, the first portable device enables communication between the first portable device and a second portable device.