Alarm system having alarm transmitter indentification codes and acoustic ranging
First Claim
1. An alarm system for sensing an alarm condition within a relevant alarm area and locating the relevant alarm area comprising:
- at least one portable alarm means for sensing an alarm condition and adapted to transmit a primary radio frequency alarm signal including an identification code upon sensing said alarm condition, said at least one portable alarm means also being adapted to transmit a secondary audio alarm signal upon sensing said alarm condition;
a plurality of transponders, at least some of said transponders being location within receiving range of said primary and secondary alarm signals, each said transponder being assigned an address code and including receiving means for receiving said primary and secondary alarm signals, recording means for recording the time of receipt of said primary alarm signal and the time of receipt of said secondary alarm signal, and transmitting means for transmitting at least said address code and indicia of the time interval between the times of receipt of the primary and secondary alarm signals by each transponder within said receiving range; and
control means for receiving signals from one or more of said transponders and for locating said relevant alarm area based upon said transponder address codes and said time intervals, said time intervals indicating the distances between a particular alarm means and respective transponders.
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Accused Products
Abstract
An alarm system for sensing an alarm condition within a relevant alarm area includes one or more portable alarm units for sensing an alarm condition. Each alarm unit includes a radio frequency transmitter for identifying the alarm unit and a secondary, audio, transmitter for defining the relevant alarm area. The system also includes a plurality of transponders. Each transponder includes a primary receiver for receiving a radio message from an alarm unit and a secondary receiver for receiving an audio signal from the alarm unit. A real-time clock in each transponder provides the elapsed time between receipt of a primary and receipt of the secondary alarm signals. The alerted transponders then transmit to a control unit a transponder address code, an alarm unit identification code and an elapsed time indicia. Based on the address code or codes and the minimal elapsed times detected by the control unit, the relevant alarm area can be determined.
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Citations
19 Claims
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1. An alarm system for sensing an alarm condition within a relevant alarm area and locating the relevant alarm area comprising:
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at least one portable alarm means for sensing an alarm condition and adapted to transmit a primary radio frequency alarm signal including an identification code upon sensing said alarm condition, said at least one portable alarm means also being adapted to transmit a secondary audio alarm signal upon sensing said alarm condition; a plurality of transponders, at least some of said transponders being location within receiving range of said primary and secondary alarm signals, each said transponder being assigned an address code and including receiving means for receiving said primary and secondary alarm signals, recording means for recording the time of receipt of said primary alarm signal and the time of receipt of said secondary alarm signal, and transmitting means for transmitting at least said address code and indicia of the time interval between the times of receipt of the primary and secondary alarm signals by each transponder within said receiving range; and control means for receiving signals from one or more of said transponders and for locating said relevant alarm area based upon said transponder address codes and said time intervals, said time intervals indicating the distances between a particular alarm means and respective transponders. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of sensing an alarm condition within a relevant alarm area and locating the relevant alarm area comprising:
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sensing an alarm condition; transmitting a primary radio frequency alarm signal upon sensing said alarm condition, such transmitting originating from within said relevant alarm area; transmitting a secondary audio alarm signal upon sensing said alarm condition, such secondary alarm signal being transmitted from the same location as said primary alarm signal; receiving said primary and secondary alarm signals at a plurality of locations; recording the time of receipt of the primary and secondary alarm signals at each of said plurality of locations; transmitting data signals from each of said plurality of locations including an address of each said location and the recorded times of receipt of said primary and secondary alarm signals at each said location; receiving said data signals from said plurality of locations at a central control point; and locating said relevant alarm area at said central control point based upon said address signals and said times of receipt. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification