Patent ID: 6806811
Filing Date: 2004-10-19
Classification: G08B

Abstract:
A perimeter alarm system using infrared energy for both the detection of a breach and communication of said breach, said perimeter alarm system comprising transceiver nodes that each receive infrared signals from one direction and transmit infrared signals in another direction, wherein;(a) said transceiver nodes are arranged to form a secure perimeter such that: (1) each of said transceiver nodes transmits a link infrared signal which includes information about the perimeter location of transmitting said transceiver node to the next one of said transceiver nodes in said perimeter; and (2) each of said transceiver nodes receives said link infrared signal from the previous one of said transceiver nodes in said perimeter; (b) one of said transceiver nodes operates as a base node to continuously transmit said link infrared signal; (c) each other of said transceiver nodes operates as a perimeter node, wherein each said perimeter node transmits said link infrared signal when receiving said link infrared signal, and ceases to transmit said link infrared signal when received said link infrared signal ceases; (d) said base node presents an alarm indication when ceasing to receive said link infrared signal; whereby an obstruction of said link infrared signals between said transceiver nodes is communicated to said base node since each of said perimeter nodes subsequent to the obstruction will be caused to cease transmission of said link infrared signals.