Chennault kept to his makeshift office, anxiously watching the telephone on his desk, which was connected to the Chinese code room, which in turn was linked to the "warning net
." At a time when radar was a recent invention and not yet widely used, many countries were employing warning nets
of different varieties.
In general, the works include the installation of structures, site installations, site preparation, signaling the site, installation of construction camps, the communication panel installation, earthworks, the up of pipes and accessories, backfilling, installing regulatory warning nets
and compacting trenches, restoration of the premises, the provisional restoration of road and sidewalks, the final rehabilitation of roads and sidewalks, supply of the file proofing.