An optical data communication and location apparatus for at least one location in a facility having at least one receiver at said at least one location. A plurality of portable transmitters provides optical wireless data links with the receiver. Each of the transmitters has a power supply with circuitry...http://www.google.com/patents/US5633742?utm_source=gb-gplus-sharePatent US5633742 - Optical data communication and location apparatus, system and method and transmitters and receivers for use therewith
