Seeing is Believing

Visual verification bolsters alarm credibility

In most communities when a burglar alarm is activated police are dispatched by a central monitoring station to a specific location to determine the cause of the signal and check on the well-being of occupants. However, because of the fact that many alarms are false (caused by some sort of human error) and police and responding authorities are overloaded and understaffed, some municipalities are experimenting with verified response or non-response if an actual intrusion cannot be verified.

To counterbalance this dangerous policy the security industry developed a widely accepted procedure called Enhanced Call Verification (ECV), which helps reduce false dispatches while still protecting citizens. ECV requires central station personnel to attempt to verify the alarm activation by making a minimum of two phone calls to two different responsible party telephone numbers before dispatching law enforcement to the scene.

The first alarm-verification call foes to the location the alarm originated. If contact with a person is not made a second call is placed to a different number. The secondary number, best practices dictate*, should be to a telephone that is answered even after hours, preferably a cellular phone of a decision maker authorized to request or bypass emergency response.

In-the-field proof that ECV practices are the best solution for false-alarm reduction while maintaining the safety of taxpayers comes from the state of Florida. As of July 1, 2006, the implementation date of the nation’s first statewide ECV law, the Palm Beach County Sheriff’s Department reduced dispatches from 12,712 between October 2005 and December 2005 to 8,802 during the same period in 2006.

Palm Beach County Deputy Charlie Mosher estimated that 80 percent of the department’s dispatch reduction can be attributed to ECV, allowing officers to spend more time in trouble spots and be more proactive on patrol. According to the Alarm Association of Florida other counties in the state have shown a similar reduction in false dispatches as well.

Following the success of Florida’s program, in May 2007 Tennessee passed legislation that requires the practice of ECV throughout the state.

To complement ECV another method the security industry developed to satisfy the requirements of verified response is cross-zoning, first introduced as a software solution for protected premises that consistently requested unwarranted dispatches.

Cross-zoning satisfies the requirements of verified response without endangering civilians who would otherwise have to determine the source of an alarm before police will respond.

To build a cross-zoned alarm system, the designer must define a protection strategy capable of sending at least two separate signals for the protection of one area. The way cross-zoning works is that identifiable signals are generated at the premises to be sent to the central station.

With multiple sensors in place to monitor one area, central-station software analyzes input from various sources to confirm if there is an intruder. If a motion detector trips in one area, the signal is recorded and the central station notifies the subscriber and others who are listed as being responsible for the alarm system. A second alarm signal, received in an adjacent zone in close time proximity (variable based on community), is the confirmation the central station needs to request a dispatch. This builds in increased protection and a fail safe for alarms caused by a door blown open or a bird rattling an exterior window.


One hardware solution to verify the need for law enforcement is impact-activated audio detection that when triggered by glass breaking or other sounds sets off a silent alarm and enables central station operators to “listen in” to sounds at the protected premises.

A second hardware solution incorporates a series of cameras to provide visual verification of the need for emergency dispatch.

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