Image Number 12 for United States Patent #7061396.
A locating and monitoring system includes transmitters worn by a person, animal, or equipment to transmit an unique identification code while moving about a facility. The code is transmitted by pulse bursts at diverse times during predetermined time intervals to prevent synchronization with resident signals in the facility. Receivers in the walls or ceilings of the facility respond to the infrared radiation of the pulse bursts and validate the identification code by a checksum of the code through a comparison with a checksum transmitted with the code. The receivers deliver validated codes to arbitrators and receive back signals indicative of the level of an individual assigned to a class wearing the transmitters. Signals from the receivers are received by arbitrators which forward the codes to a CPU for recording start and stop events indicative of movement by transmitters into and out of the reception range of the various receivers.