The function of interior detection is to keep safe and protect a home’s occupants and contents from intruders. The primary features of interior security include:

•    Access control    A process that allows or denies access, or entry, to the home itself or to a particular area. Typically, access control systems require the entry of codes, the use of a key, an access card, a proximity card, or a physiological characteristic of a person, such as hand or thumb print. Access control can be as simple as a mechanical lock and key or as sophisticated as biometrics, which is an access control method that uses fingerprints, retinal scans, and the like.

•    Intrusion detection    The opening of a door, a window breaking, a shock or vibration on a surface, or even a motion in a secured area can create a notification or an event that triggers an alarm to sound, or sends an intrusion alert message to an external security monitoring service that then contacts the local police and fire departments.

•    Smoke, fire, and dangerous gas detection    Independent or integrated sensors can detect smoke, the heat from a smokeless fire, and even carbon monoxide or radon gases and sound a built-in alarm, send an alarm signal to a central security system controller, or relay a message to an external security monitoring service.

•    Panic buttons    Though they are not found in all security systems, a panic or emergency alert feature can be a desired feature for some customers. Typically, a centrally or conveniently placed button or a special sequence of digits on the telephone or alarm keypad can be used to sound an alarm or to transmit an emergency request to the monitoring service to dispatch the local emergency services or the police department.

Chapter 19: Security System Basics

•      Environment sensors    Optional temperature and humidity sensors can be
installed to monitor the environment. Low temperature sensors can detect
when the heat goes too low and notify the monitoring service or indicated
parties prior to the pipes freezing and bursting. Humidity and temperature
sensors help maintain the correct environment for wine cellars and cigar rooms.
Flood or water sensors can detect when water is at a level it shouldn’t be, such
as when a sump pump fails or a pipe breaks in the basement.

Numerous studies have shown consistently that the homes with the most risk of crime typically have the least protection. And in a significant percentage of these homes, there is no protection or warning systems installed beyond door locks and fencing. Those homes that do have some type of protective system commonly have some form of burglar alarm, but even this is only common in more expensive homes.
Of course, protection is the main purpose of a security system. However, the primary benefit of a residential security system is not necessarily protection, but rather the peace of mind that comes from having a security system installed.
The type and technology of a residential security system should be fitted to the home, lifestyles, and level of protection desired by the homeowners. In this chapter, we look at security system basics, including the various types of systems available, their components, the communications technologies they employ, and a few of the external services that can be used for monitoring.