75259052
Mar 18, 1997
May 18, 1999
underground radiating line communication systems comprised of amplifiers, radiating transmission cable, head end units for terminating a radiating transmission cable, end units for terminating a length of radiating transmission cable, branch units for branching two or more radiating transmission cables, and power supplies for communicating voice, video and computer information to and from underground locations utilizing radio frequency signals
Electrical and Scientific Apparatus