IN THE EARLY 19TH CENTURY, FIRE ALARMS WERE PASSED BY WORD OF MOUTH TO THE CITY HALL BELL RINGER, BUT THIS METHOD WAS SLOW AND OBSCURED THE SITE OF THE FIRE. A SERIOUS NEW YORK CITY FIRE IN 1835 LED OFFICIALS IN THAT CITY TO PROVIDE EACH CITY DISTRICT WITH ITS OWN FIRE SIGNAL IN ORDER TO SPEED UP FIREFIGHTING RESPONSE (A REFINEMENT OF THIS SYSTEM IS STILL USED TODAY). LATER DEVELOPMENTS INCLUDED RUNNING TELEGRAPH LINES TO FIRE TOWERS TO PROVIDE DIRECT COMMUNICATION TO FIREFIGHTERS (A FORERUNNER OF THE 'CALL BOX') AND THE DELINQUENCY SIGNAL IDEA IN WHICH AID IS RUSHED TO A FACTORY OR OTHER BUILDING IF ITS WATCHMAN FAILS TO CALL IN AT A SPECIFIED TIME. MANY TCHNICAL IMPROVEMENTS IN SECURITY ALARM SYSTMES WERE DEVELOPED DURING AND AFTER WORLD WAR II, INCLUDING THE USE OF ULTRASONIC ENERGY SIGNALS TO STOP ENDANGERED VEHICLES, MOTION DETECTORS, AND DETECTING THE PRESENCE OF INTRUDERS WITH SENSITIVE ANTENNAE (ESPECIALLY GOOD FOR PROTECTING ART OBJECTS). THE GLOSSARY IS ARRANGED ALPHABETICALLY AND CONTAINS ABOUT 160 TERMS. CATEGORIES OF TERMS INCLUDE TYPES OF FIRE AND INTRUDER DETECTION SYSTEMS; ALARMS; PARTS OF AN ALARM SYSTEM, INCLUDING CIRCUITS AND SWITCHES, PROTECTION ZONES, AND BARRIERS; AND TYPES OF ACTIVITIES INVOLVED IN IMPLEMENTING SECURITY SYSTEMS. (PAP)