The Language of Security Systems

Security systems of today, have complicatedtakes care of accepting coded signals from number
mechanisms, but alarm terminology has basically, notkeypads used to arm/disarm the system. Every
changed.system has at least one keypad, but many have 2 or
If you're looking for a home security system, here's3 (one in the main entry foyer or laundry room off
some terminology language and lingo.the garage, one in the master bedroom, and maybe
Radio Frequency is a wireless method of transmittingone in the Family room). The user enters a
a signal from a door, window, or motion sensor topreselected arm/disarm code (1357 or whatever
the Control Panel. If the system is armed, and thecombination the user wants). The code either arms
zone is active, it would trip the alarm. If the systemor disarms the system. It will also reset an alarm. The
is NOT armed, or the zone is turned off, nothing willControl Panel also monitors smoke detectors, which
happen.are always active.
Supervised: Most wireless alarm systems today areIn most modern alarm systems, voice communication
supervised. This means each sensor within theis active. This means, when an alarm signal is sent to
system has its own code number. When it transmitsthe Central Station, the operator opens something
a signal (a door opens or a motion sensor is tripped),similar to a phone circuit. He/She can talk and listen to
the Control Panel will identify the signal that itthe house. Listening is often ineffective because of
receives by the sensor's code number. Supervisionthe loud alarm siren. When the system is reset, the
also enables the Control Panel to know and identify aoperator and the user can talk as if they were on a
sensor that reports a low on-board battery.telephone. If there is a crisis, the operator can be
Door and window contacts are two pieces; a magnetmade aware, and appropriate help dispatched (police,
and a contact switch. They are always mounted sidefire, ambulance). If the user is not home, the
by side (sometimes they are drill mounted in doors).operator can continue to listen to the house while
When the magnet is separated from the switch, fordispatching police.
instance, a door opens, and if the system is armed,Delayed entry/exit doors are becoming obsolete
an alarm will sound. If the system is not armed,because of the use of tiny key fobs (button devices
nothing happens, (but the Control Panel knows andsimilar to those used to arm/disarm vehicle alarms).
sometimes keeps a log of the time and date when aBut there is still a bunch of them out there. A
given door, or other sensor was activated. However,delayed entry/exit door(s) is programmed and
no alarm was actually triggered.monitored by the Control Panel. If User A leaves the
Motion sensors can be wired or wireless. There arehouse, they would arm the system at the number
several different kinds of motion sensors, Ultrasonic,keypad (say, 1357). Then open the delayed door and
Microwave Infrared, or a combination of both. Theexit. The system will allow any amounts of
most sensitive of these sensors is Microwave. Theypreselected time for the exit process. After the exit
can see through doors, walls, windows, just aboutwindow has closed (say 60 seconds), the door is
anything except metal. They can cause a lot of falsearmed. When User A returns, they enter thru the
alarm problems because of their long range andsame door. The entry window is usually very short,
sensitivity. Ultrasonics aren't used that muchmaybe 20 or 30 seconds. This allows the user to
anymore, as they were false alarm-prone.walk to the keypad and enter the combination (1357)
Most motion sensors today use Passive Infrared orto disarm the system.
heat sensitive technology. The sensor, detectsA nice feature of the newer keypads/Control Panels
motion, measures the difference in the temperatureis protection against forced entry (for instance, bad
of the room, and that of a human body (98.6 versesguy forces User A into the house and tells her to
72 degrees). When it sees the two differentdisarm the alarm). If the arm/disarm code is 1357,
temperatures, it sends a signal to the Control Panel,she might enter 1358. This code will disarm the alarm
which trips an alarm. Interior traps (motion sensors)system, but it also sends a silent alert to the Central
can be zoned off, so that a user can walk aroundStation. They will have been programmed in advance
their home without tripping an alarm, but the sensorto listen to the house, but make no sound. Once
is never actually turned off. The zone the sensor isthey determine there is a real problem, they notify
located in, is turned off. The viewing pattern ofpolice and stay on the line with both the house and
Infrared sensors can be modified, using scotch tape.the police to remain updated while authorities drive to
This is often done to 'raise the pattern' so the sensorthe house.
does not detect dogs or cats, and only sees motionMany systems have inside and/or outside siren
of, say, 3 feet or more off the floor.speakers. The idea is to scare the intruder away, not
Control Panels are computers that keep track of andcatch them. I always used inside speakers. Reason: if
process signals from the various sensors (door,bad guys are trying to get IN, I want them to hear
window, motion, glass breakage, under-carpet floorthe siren. Many outside speakers can't be heard from
mats, etc.). They also report alarm conditions to ainside.
Central Station when triggered. The Control Panel