Patent ID: 6084509
Filing Date: 2000-07-04
Classification: G08B

Abstract:
An apparatus for use in a multi-zone alarm system having a single-pair wire alarm loop and programmable switching circuit arrangements, said apparatus comprising:a current source serially connected to said single-pair wire loop and selectively operative to provide a predetermined current signal in said loop;a plurality of zone sensing means arranged in a normally closed series circuit along said single-pair wire loop, each said zone sensing means including resistance means coupled in parallel within each of the normally closed series circuit zone sensing means for providing a specific voltage upon its creating an open circuit in said loop circuit to generate coded voltage changes and alarm activation caused by an open circuit created therein, the resistance exhibited by the resistance means of said plurality of normally closed series connected zone sensing, means being doubled in each sequentially disposed adjacent zone sensing means to create different specific voltages to generate said coded voltage changes;means for indicating the condition of each said zone sensing means;means for selectively arming and disarming said zone sensing means;means for indicating an open circuit in said single-pair wire loop unrelated to the condition of said zone sensing means;circuit means operative in response to said zone sensing means to provide a signal indication of the zone in which alarm activation has occurred; andmeans for continuously monitoring all circuit conditions of said apparatus in both said armed and disarmed operative conditions.