FLEXALERT

UNDERGROUND COMMUNICATION SYSTEM COMPRISED OF TELEMAGNETIC TRANSMITTERS, ELECTROMAGNETIC TRANSMITTERS, ANTENNAS AND RECEIVERS; ANTENNAS FOR GENERATING LOW FREQUENCY ELECTROMAGNETIC FIELDS; TELEMAGNETIC TRANSMITTERS AND ELECTROMAGNETIC TRANSMITTERS; RECEIVERS; COMPUTER SOFTWARE TO MONITOR, ACQUIRE AND/OR CONTROL DATA IN A COMMUNICATION SYSTEM

INSTALLATION AND MAINTENANCE OF COMMUNICATION SYSTEMS, ANTENNAS, TRANSMITTERS AND RECEIVERS