Low cost RF identification and locating system

A security system which enables the user to locate immediately any personnel in a building is described. This system uses a network of receiver units to pick up identification (ID) codes transmitted from portable transmitters worn by all personnel in the building. The ID codes are collected from the receiver units by a central processor via a communication line. The central processor then updates a database and presents the information to the user. A special communication protocol which enhances the communication between the receivers and the central processor through selected networks has also been designed. This protocol increases the bit efficiency of the information transfers