Apparatus for determining break locations in fencing

Abstract

An improved intrusion detection apparatus for detecting when a fence is cut r has been climbed over, as well as the location of the intrusion. A cable comprising at least one optical fiber having an electrical transmission line running therealong is strung along the fence to be protected. If an intruder either cuts the cable or stresses the fence so that the cable breaks, an optical signal running along the optical fiber or fibers is lost, thus providing an alarm indication at a central station. The loss of the optical signal automatically triggers an electrical pulse generator means which feeds pulses down the transmission line running along the optical fiber. Part of the pulse energy is reflected at the transmission line break, and the time elapsed between transmission and receipt of the pulses is determined by time domain reflectometry techniques (TDR).

Dependencies are inferred from the claim text.