The most basic definition of any security system is found in its name. It is literally a means or method by which something is secured through a system of interworking components and devices.
Home security systems work on the simple concept of securing entry points into a home with sensors that communicate with a control panel or command center installed in a convenient location somewhere in the home.The sensors are typically placed in doors that lead to and from a house as well as easily accessible windows, particularly any that open, especially those at ground level. Open spaces inside of homes can be secured with motion sensors.
The control panel is the computer that arms and disarms the security systems, communicates with each installed component, sounds the alarm when a security zone is breached and communicates with an alarm monitoring company.