Keypad: This is where the system is armed and disarmed. Additional keypads can be installed.

Control Panel: This is the location where the system wiring terminates, the backup battery is located, and where it is connected to the phone lines if it is a monitored system.

Siren: A loud siren sounds when there's been a break-in and it also lets an intruder know they've been detected.

Door and Window Contacts: Magnetic contacts form a circuit between a door and doorframe or a window and a sill; when the door or window is opened (and the system is on), the circuit is broken and sounds the alarm.

Inside Motion Detector: Passive infrared, microwave, or photoelectric detectors sense changes in a room caused by human presence. Special motion detectors are available for people who have pets.

A Central Monitoring Station (Company): If the system is monitored, in the event of an alarm, the control panel sends a message over a telephone line to a central monitoring station, which is manned 24 hours a day. After attempting to contact the homeowner, the central monitoring station will contact the police, fire department, or medics. There is usually a monthly fee for this service.

Additional items that can be added to the basic system are:

Smoke Detectors are required by many building codes. They can be wired to the security panel. If the smoke detectors go into alarm, the security panel will notify the central monitoring station if smoke is detected.

Carbon Monoxide Sensors

Glass Break Detectors recognize the sound of glass breaking and will sound the alarm.

Panic Buttons can be hand-held and should be located in strategic places such as next to beds and doors; just punching the button will send a message to the central monitoring station for help.

Closed circuit TV is a private TV system which allows monitoring and/or recording inside or outside a home.

Alarm Screens are special screens for windows that have a special wire woven in the mesh that will activate an alarm when cut or removed.

Wireless Backup Radio If the system is monitored, in the event of an alarm, the control panel sends a message over a wireless radio transmission to a central monitoring station.