1. Keypad: This is a small box with a numbered faceplate that performs two main functions: to initiate security commands, and to display the status of the security system. Keypads include an alphanumeric keypad and an LED display. Homeowners enter a predetermined code to activate the alarm when they are leaving the property, and to deactivate it when they return home. Many keypads include a panic switch to alert the system immediately in case of emergency, as well as a bypass function that lets the homeowner customize the system to bypass areas where family members may be present. The LED display shows the status of the alarm system; that is, whether or not the system is active.

2. Sensors: These protect the perimeter of the home, as well as open spaces inside. Most common sensors used in home security equipment are window vibration detectors, magnetic door or window switches and acoustical detectors. These sensors are installed on doors and windows to prevent intruders from entering the house. Space protection sensors can also be installed to detect intruders within hallways and interior rooms.

* Window acoustic and vibration detectors are able to detect the sound of breaking glass, and then trigger the alarm. These devices make it nearly impossible to enter a home by breaking glass windows or doors.

* Door switches are made of two components: a switch and a magnet. The switch is sensitive to a magnetic field and is mounted on a fixed structure like a door or window frame. The magnet is mounted on the door next to the switch. If the door is opened while the system is activated, the magnet will move away from the switch and will trigger the alarm.

* Motion detectors will pick up on changes in infrared energy. Available in three levels of security (standard, pet-friendly and harsh environment outdoor devices) motion detectors alert the system to trigger the alarm when an intruder enters the open space.

3. Cameras: Not all home security equipment packages include cameras, but the added protection they provide can be worth the additional investment. Cameras collect and transmit visual images of intruders, and show the images on a video monitor.

4. Monitors: Working with security cameras, video monitors allow homeowners or security personnel the opportunity to watch the property and see potential intruders before the break-in occurs. The information is transmitted through coaxial cables from the cameras.

5. Some security systems will include more than one camera. Switchers process images generated by several cameras, and enable the operators to switch from camera to camera to scan a large area of activity.

Home security equipment is varied in terms of quality and price. Shop around before you buy, to determine the package that is best suited to protect your home and family.