3.0—Home Security and Surveillance Systems

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Chapter
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3
Physical Devices
The six major physical components of a home security and surveillance system
are described in this section. Although some designs include additional
components for enhanced performance or custom installations, the physical
devices described here are considered the basic building blocks for a security
and surveillance system that will provide adequate protection from intrusion.
The essential physical assemblies include
➤ Keypads
➤ Sensors
➤ Security panels
➤ Cameras
➤ Monitors
➤ Switchers
Keypads
The keypad is the device used by the home residents to initiate commands
for control options and observe the status of the security system. As shown
in Figure 3.3, it usually contains an alphanumeric keypad and LED displays
that indicate the status of the alarm system.
Figure 3.3 Keypad.
The keypad is used to arm and disarm the system and often includes a panic
switch by which the alarm can be triggered instantly in an emergency situation.
The alarm can be silenced by the owner by entering the correct coded
sequence of numbers on the numerical keypad. The keypad is typically
installed inside the home near a door that is most frequently used by the residents.
A programmed delay is included as a feature of most systems to
enable the users to enter and disarm the system within a fixed delay period
(normally 30–45 seconds). The same fixed delay is also used to allow the user
to arm the system and exit the home within the fixed delay period. Keypads
can also be used to bypass certain areas.
The bypass function is used to arm the system but disable selected zones or motion
detectors inside the home when the family is present. Residents often desire to secure
the perimeter area of doors and windows after retiring for the evening but need to
bypass interior area motion detection sensors that are activated only when the home
is not occupied.