Patent US 4,225,953

A personnel locator and display system for indicating on a status board the room numbers where designated key individuals are located at a given moment. Small portable transmitters, either ultrasonic or radio frequency, are worn by the key individuals, and receivers are provided in the rooms. The various transmitters emit pulses according to a preprogrammed timing sequence, and a decoding logic network connected to receive signals received in the rooms identifies the specific transmitter and room number and displays same on a status board. A programmer-recharger unit programs the pulse timing for each transmitter for identification of the wearer.