75170225
Sep 23, 1996
Sep 7, 1999
spread spectrum wireless audio-visual emergency and communication system, comprising wireless radio transceivers, computers with graphical user interface displays, directional antennas, wireless audio speakers, wireless visual displays, namely, LED programmable electronic message boards, wireless radio transmitters, wireless radio receivers, wireless spread spectrum transmitters, wireless spread spectrum receivers, and emergency call-box units
Electrical and Scientific Apparatus