Information on Burglar Alarms

Types of Alarm Systems

• When planning insulation of a burglar alarm, consider the three basic types of alarm systems: wireless, hardwired and self-contained. Hardwired systems have wires running from each sensor to a central control panel. Wireless systems use radio waves instead of wire to connect the control panel and detection devices. A self-contained system is a unit disguised as a household electronic appliance--such as a VCR, tape deck or toaster.

Alarm Components

• The components of an alarm system consist of a main control unit, a sounder or siren and one or more detection devices. On a hardwired system, wire is connected from each sensor to the main control panel. The control unit is programed to sound immediately or after a short time delay. Some systems are configured to only send a silent signal to a monitoring station or law enforcement agency. A control unit, positioned at the point of entry, is used for arming and disarming the security system.

Detection Devices

• Magnetic switches effectively protect doors and windows. The magnetic contacts are cost-effective, reliable units that are easily installed. Magnetic contacts consist of two components: a switch and a magnet. Within the switch, a spring-loaded contact closes to complete an electrical circuit when the magnet is applied. When a window or door or secured and closed, the electrical circuit is complete. When an entry point is opened, the circuit is broken and an alarm is issued. Ultrasonic detectors use high-frequency sound waves to detect motion in the protected area. Sound waves are bounced off floor, ceiling and walls until the frequency is stabilized. An alarm condition is signaled when an intruder enters the room and disrupts the sound waves. Monitoring infrared radiation, passive infa-red sensors (PIR) or "rate-of-rise" detectors sense rapid changes in temperature. Highly effective, PIR detect the radiation given off by all living things. The unit ignores gradual changes in temperature from air conditioners, furnaces or sunlight. If an intruder enters the protected perimeter, an alarm is sounded. These units can be programed so that they are not triggered by a small pet, bird, mouse or squirrel.

Areas of Coverage

• Both wireless and hardwired burglar alarm systems can be set up to exclude certain areas of the premises. A master bedroom may have the alarm system activated while the remainder of the house remains open. Be aware of the problems inherent in inexpensive and poorly installed alarm systems. False alarms, or failure to alert in the case of entry, can be costly. Many police jurisdictions charge for responding to a false alarm. Repeated false alarms cause neighbors and law enforcement to disregard the alarm when help may be most needed.

Monitoring

• A local alarm sounds only in the area where it is installed. It relies on others to investigate and call the police if needed. It is a deterrent in that it may scare away a burglar, but is not as effective as a monitored system. A monitored system uses automated telephone connections to a central monitoring station which evaluates the alarm and sends the appropriate response. Medical, fire, carbon monoxide, panic and home invasion alarms are vital components of an effective security system. A monitored system can also auto-dial the homeowner's cell phone when the security of the home is breached.