NCJ Number
57760
Date Published
1977
Length
4 pages
Annotation
A PORTABLE RF ALARM LINK THAT PROVIDES A MEANS OF MONITORING WIDELY SEPARATED DETECTORS FROM A CENTRAL LOCATION IS DESCRIBED. THE SYSTEM HAS PROVEN EFFECTIVE IN PROTECTING TEMPORARY/INSTALLATIONS.
Abstract
THE SYSTEM CONSISTS OF UP TO 10 REMOTE STATIONS AND A BASE STATION WHICH IS TRANSPORTED IN AN ALUMINUM CARRYING CASE. THE SYSTEM CAN BE OPERATED BY BATTERIES OR BY ELECTRICAL CURRENT. EACH REMOTE UNIT CONSISTS OF A TRANSMITTER WHICH RADIATES AN ALARM SIGNAL UPON CLOSURE OR OPENING OF A PAIR OF SWITCH CONTACTS CONTROLLED BY THE DETECTOR. UPON RECEPTION OF AN RF ALARM SIGNAL, THE BASE STATION DETERMINES WHICH STATION IS BEING RECEIVED AND VISUALLY DISPLAYS THE STATION NUMBER WHILE ACTIVATING AN AUDIO ALARM. IN ADDITION, THE SYSTEM INCORPORATES A MEANS OF MONITORING THE OPERATING CONDITIONS OF EACH REMOTE UNIT. MODULATING TECHNIQUES USED IN THE SYSTEM ARE SELF-SYNCHRONIZING, SECURE, AND PROVIDE A HIGH PROBABILITY OF RECOGNITION OF REMOTE STATION ALARM INDICATIONS WITH A LOW FALSE ALARM RATE. THIS SYSTEM OFFERS THE ADDITIONAL ADVANTAGES OF BEING EASILY CARRIED AND SET UP. IT IS ALSO ADAPTABLE TO A VARIETY OF DETECTION DEVICES. ILLUSTRATIONS, DIAGRAMS, AND REFERENCES ARE INCLUDED. (KCP)