Patent ID: 6960987
Filing Date: 2005-11-01
Classification: G08B

Abstract:
1. A fire alarm system for connecting a plurality of fire sensors to sensor lines drawn from a fire receiver, and giving an alarm in response to a fire information signal output from the fire sensor in a line unit, said fire alarm system comprising: current modulation means, provided in said fire sensors, for maintaining a sensing current supplied from said fire receiver at a predetermined value for a predetermined time at the time of a fire, and modulating said sensing current in accordance with inherent address information of said fire sensor after said predetermined time; and address specification means, provided in said fire receiver, for sensing fire information by judging whether or not said sensing current has been maintained at said predetermined value for said predetermined time, and also for specifying the inherent address of the fire sensor that issued said fire information, from a modulated state of said current after said predetermined time.