Burglar (or intrusion) Alarm System Component Details
Burglar (or intrusion),
fire, and safety alarms are electronic alarms designed to alert
the user to a specific danger. Sensors are connected to a control unit via
low-voltage wiring or a narrowband RF signal which is used to interact with a
response device. The most common security sensors are used to indicate the
opening of a door or window or detect motion via passive infrared (PIR). New
construction systems are predominately hardwired for economy. Some installations
often use wireless systems for a faster, more economical installation. Some
systems serve a single purpose of burglar or fire protection. Combination
systems provide both fire and intrusion protection. Systems range from small,
self-contained noisemakers, to complicated, multi-zoned systems with
color-coded computer monitor outputs. Many of these concepts also apply to
portable alarms for protecting cars, trucks or other vehicles and their
contents (i.e., "car alarms"). See also fire alarm control panel for
specific fire system issues. Burglar alarms are sometimes referred to as alarm
systems, see burglar alarm control panel for a discussion of hard-wired
burglar alarm system design.
Burglar
alarms (or perimeter detection systems, Perimeter protection, intrusion
detection systems and many more terms for the same thing) are divided to
two main fields: home burglar alarms and industrial burglar and perimeter
intrusion detection.
Intruder
Panel
These are
reliable and easy to use and offers enhanced fire detection and external
lighting control facilities, conforming to CE specification directives and
BS4737 standards.
The salient features are:
Zones - Each zone is separately identified on the keypad and provides ample
security detection for most domestic properties. Typically 4zone. 8zone, 16
zone panel in market. Currently some hybride panel also there (eg: 4 Hardware
Zone + 8 wireless Zone)
3 Part Set Programs - Allows three programmed setting levels dependent on the
people in the property or the level of protection required.
Simple Set Readers for Ease of Operation - Up to 4 stylish readers can be used
to set/unset the system using a proximity keyfob.
Personal Attack Facility - Any number of PA buttons may be set to activate the
system in an emergency.
Remote Keypads for added Flexibility - Up to four keypads can operate the
system from any point in the property.
Input for Remote Keyswitch or Push to Set Switch - A remote keyswitch or push
can be used to set or unset the system.
Fire Zone - Any number of zones can be programmed as a fire zone. Two types are
available: Standard Fire - operated only whwn system has been set; 24 hour -
operates all the time.
Lighting Control Feature - Full manual and automatic control over security
lightng.
Duress Code - Allows the user to unset the system and silence the alarm under
duress, using a second code that will communicate an alarm to an alarm
receiving center.
Chime - Can be used to select a low security chime alarm for various areas of
the protected area, even when the main alarm is turned off.
Built-in tamper control.
Indoor
These types
of sensors are designed for indoor use. Outdoor use would not be advised due to
false alarm vulnerability and weather durability.
Motion detector
A motion
detector is a device that contains a physical mechanism or electronic
sensor that quantifies motion that can be either integrated with or connected
to other devices that alert the user of the presence of a moving object within
the field of view. They’re a vital component of comprehensive security systems,
for both homes and businesses.
An
electronic motion detector contains a motion sensor that transforms the
detection of motion into an electric signal. This can be achieved by measuring
optical or acoustical changes in the field of view.
A motion
detector connected to a burglar alarm that is used to alert the home owner or
security service after it detects motion. Such a detector may also trigger a
red light camera.
An occupancy
sensor is a motion detector that is integrated with a timing device. It senses
when motion has stopped for a specified time period in order to trigger a light
extinguishing signal. These devices prevent illumination of unoccupied spaces like
public toilets.
There are
basically three types of sensors used in motion detectors spectrum.
- Passive Infrared sensors (PIR)
- Looks for body
heat. No energy is emitted from the sensor.
- Ultrasonic (Active)
- Sensor sends
out pulses and measures the reflection off a moving object.
- Microwave (Active)
- Sensor sends
out microwave pulses and measures the reflection off a moving object.
Similar to a police radar gun.
Passive
infrared detectors
The passive
infrared detector (PIR) is one of the most common detectors found in household
and small business environments because it offers affordable and reliable
functionality. The term passive means the detector is able to function
without the need to generate and radiate its own energy (unlike ultrasonic and
microwave volumetric intrusion detectors that are “active” in operation). PIRs
are able to distinguish if an infrared emitting object is present by first
learning the ambient temperature of the monitored space and then detecting a
change in the temperature caused by the presence of an object. Using the
principle of differentiation, which is a check of presence or nonpresence, PIRs
verify if an intruder or object is actually there. Creating individual zones of
detection where each zone comprises one or more layers can achieve
differentiation. Between the zones there are areas of no sensitivity (dead
zones) that are used by the sensor for comparison.
The salient
features of the range of movement detectors are as follows:
Look Down Technology - Dual lookdown zones are employed to ensure that even the
most determined intruder will be detected.
NC/NO Selectable Outputs - Products are fitted with changeover relays to ensure
compatibility with all requirements.
White Light Filter Lens - To minimize any possibility of problematic alarms due
to fluorescent / environmental conditions.
Intelligent Pulse Counts - Reduces the possibility of false alarms caused by
environmental and power line interference.
Sealed Optics - The sensor element is sealed, to prevent unwanted small insects
form accessing the sensor area.
Dual-technology
motion detectors
Many modern
motion detectors use a combination of different technologies. These
dual-technology detectors benefit with each type of sensor, and false alarms
are reduced. All companies have the option to use PIR/Microwave Motion
Detectors that have "Pet-Immune" functions which allow the detector
to ignore pets that weigh up to 80 pounds. Placement of the sensors can be
strategically mounted so as to lessen the chance of pets errantly activating
alarms.
Often, PIR
technology will be paired with another model to maximize accuracy and reduce
energy usage. PIR draws less energy than microwave detection, and so many
sensors are calibrated so that when the PIR sensor is tripped, it activates a
microwave sensor. If the latter also picks up an intruder, then the alarm is
sounded.n it is also used in burglar alarm. As interior motion detectors do not
‘see’ through windows or walls, motion-sensitive outdoor lighting is often
recommended to enhance comprehensive efforts to protect the property.
Panic
Button
Panic
buttons are targeted and rapid mode of contact used primarily by sick and old
people to contact their care takers at times of distress or during emergency
situations. It offers either visual or acoustic signaling. The signals can also
be routed to the wireless devices carried by their caregivers, enabling a fast
and quick response. This system typically consists of a main communicator panel
and the multiple points connected to it.
Ultrasonic
detectors
Using
frequencies between 25 kHz and 75 kHz, these active detectors
transmit ultrasonic sound waves that are inaudible to humans. The Doppler shift
principle is the underlying method of operation, in which a change in frequency
is detected due to object motion. This is caused when a moving object changes
the frequency of sound waves around it. Two conditions must occur to
successfully detect a Doppler shift event:
- There must be motion of an object either
towards or away from the receiver.
- The motion of the object must cause a
change in the ultrasonic frequency to the receiver relative to the
transmitting frequency.
The
ultrasonic detector operates by the transmitter emitting an ultrasonic signal
into the area to be protected. The sound waves are reflected by solid objects
(such as the surrounding floor, walls and ceiling) and then detected by the
receiver. Because ultrasonic waves are transmitted through air, then
hard-surfaced objects tend to reflect most of the ultrasonic energy, while soft
surfaces tend to absorb most energy.
When the
surfaces are stationary, the frequency of the waves detected by the receiver
will be equal to the transmitted frequency. However, a change in frequency will
occur as a result of the Doppler principle, when a person or object is moving
towards or away from the detector. Such an event initiates an alarm signal.
This technology is considered obsolete by many alarm professionals, and is not
actively installed.
Microwave
detectors
This device
emits microwaves from a transmitter and detects microwaves at a receiver,
either through reflection or reduction in beam intensity. The transmitter and
receiver are usually combined inside a single housing (monostatic) for indoor
applications, and separate housings (bistatic) for outdoor applications.
By
generating energy in the microwave region of the electromagnetic spectrum,
detector operates as an active volumetric device that responds to:
- A Doppler shift frequency change.
- A frequency phase shift.
- A motion causing reduction in received
energy.
Photo-electric
beams
Photoelectric
beam systems detect the presence of an intruder by transmitting visible or
infra red light beams across an area, where these beams maybe obstructed. To improve
the detection surface area, the beams are often employed in stacks of two or
more. However, if an intruder is aware of the technology’s presence, it can be
avoided. The technology can be an effective long-range detection system, if
installed in stacks of three or more where the transmitters and receivers are
staggered to create a fence-like barrier. Systems are available for both
internal and external applications. To prevent a clandestine attack using a
secondary light source being used to hold the detector in a ‘sealed’ condition
whilst an intruder passes through, most systems use and detect a modulated
light source.
Glass
break detectors
A glass
break detector is a device that detects a break in a pane of glass,
alerting a burglar alarm. If it detects broken glass, and the alarm is set,
then it sets off the alarm.
It used for
internal perimeter building protection. When glass breaks it generates sound in
a wide band of frequencies. These can range from infrasonic, which is below 20
Hertz (Hz) and can not be heard by the human ear, through the audio band from
20 Hz to 20 kHz which humans can hear, right up to ultrasonic, which
is above 20 kHz and again cannot be heard. Glass break acoustic detectors
are mounted in close proximity to the glass panes and listen for sound
frequencies associated with glass breaking. Seismic glass break detectors are
different in that they are installed on the glass pane. When glass breaks it
produces specific shock frequencies which travel through the glass and often
through the window frame and the surrounding walls and ceiling. Typically, the
most intense frequencies generated are between 3 and 5 kHz, depending on
the type of glass and the presence of a plastic interlayer. Seismic glass break
detectors “feel” these shock frequencies and in turn generate an alarm
condition.
Acoustic
Glassbreak Detectors employ a microphone, which "listens" for the
sound(s) created by breaking glass. These sounds are typically recorded,
digitized and then compared to a library of other sounds/events to determine if
in fact glass was broken or a false alarm occurred.
There are
several types of window break detectors, one kind detects the vibrations of the
window, and if the vibrations get too high/ the window breaks the alarm goes
off. Basically the device tells whether or not the window is broken by
measuring the vibrations. Another kind detects the noise of glass breaking.
Magnetic Door Contact
Magnetic
Door Contact detectors identify intruders by using a magnet and reed switch
mechanism. The reed switches are electrical contacts held open by the presence
of a magnet. When a magnet attached to an opening door moves away from the reed
switches in the alarmed sensor, the switches make contact with each other and
trigger a radio frequency (RF) transmission to the system control panel.
Information in the RF transmission identifies the type and location of the
sensor.
Magnetic
Door Contact Detectors can be surface-mounted or recessed. Absence of any
external wiring provides the installer with unlimited scope to place the device
in positions where it is hidden from view. The detector is a truly stand alone
module containing the low power viper integrated circuit, identification and
encoding electronics, scantronic transmitter, integral aerial and battery.
Salient
features include:
Simple calibration
Exclusive double knock facility at point of attack
Wire free
Scantronic 4600 series compatible
Adjustable detection sensitivity
Fully approved transmitter
Integral magnetic door contact
LPG Gas Detector
LP gas
(butane or propane) is the most common type of fuel used for cooking and
heating worldwide. LPG leak can cause devastating explosions and consequences
of a gas leak in both domestic and commercial situations are every bit as
disastrous as those of a fire and can be avoided with the fitting of easy to
use and cost effective detection equipment.
Feature and Benefits are as follows:
Officially approved to BS7348 (The British Standards for Domestic Gas
Detectors).
Proven semiconductor sensor technology.
230Vac or 12Vds versions.
Relay output models are available.
Suitable for home, caravan and commercial use.
Easy to install and use with no maintenance.
Smoke,
heat, and carbon monoxide detectors
Smoke
Detectors provide the earliest practicable fire detection and warning. This
system consists of smoke or heat detectors at designated locations, to detect
smoke or heat at the earliest during any outbreak of fire. The various types of
detectors used in this system are Photoelectric, Heat and Multisensing. The
detectors are selected based on certain pre-determined parameters. On sensing
fire the system initiates a warning alarm, thereby alerting the occupants.
Most systems
may also be equipped with smoke, heat, and/or carbon
monoxide (CO) detectors. These are also known as 24 hour zones
(which are on at all times). Smoke detectors and heat detectors protect from
the risk of fire and carbon monxide detectors protect from the risk of carbon
monoxide.
Auto
Dialer
The communicator / auto dialer is pre programmed to place 4 automatic calls to
any pre set destinations, which could include the owner, other two important
numbers and one to the Central Monitoring System (CMS).
The salient features are:
Up to four keypads per control panel
Full LCD status indication
Illuminated keys
On-board PA facility Entry / exit tones
Programmable user strings
Programmable backlight options for keypad and LCD display.
Outdoor
These types
of sensors would be found most of the time mounted on fences or installed on
the perimeter of the protected area.
Vibration
(shaker) or inertia sensors
These
devices are mounted on barriers and are used primarily to detect an attack on
the structure itself. The technology relies on an unstable mechanical
configuration that forms part of the electrical circuit. When movement or
vibration occurs, the unstable portion of the circuit moves and breaks the
current flow, which produces an alarm. The technology of the devices varies and
can be sensitive to different levels of vibration. The medium transmitting the
vibration must be correctly selected for the specific sensor as they are best
suited to different types of structures and configurations.
More
sophisticated sensors use piezo-electric components rather than mechanical
circuits, which can be tuned to be extremely sensitive to vibration. These
sensors are more durable and more resistant to tampering.
- pros: Very reliable sensors, low false
alarm rate and middle place in the price range.
- cons: Must be fence mounted would be the
main con. Its rather high price deters many customers, but its
effectiveness offsets its high price.
The Salient feature
are as follows:
Removable Electronics
Non gravity dependent
Dual memory LED and relay
Walk test facility
Remote rest
Dual stage sensitivity
Sensitivity potentiometer
LED lens relay auto resets
Surface mount technology
Anti condensation base
Door contact option
Double knock link
Passive
magnetic field detection
This buried
security system is based on the Magnetic Anomaly Detection principle of
operation. The system uses an electromagnetic field generator powering with two
wires running in parallel. Both wires run along the perimeter and are usually
installed about 5 inches apart on top of a wall or about foot buried in
the ground. The wires are connected to a signal processor which analyzes any
change in the magnetic field.
This kind of
buried security system sensor cable could be buried on the top of almost any
kind of wall to provide a regular wall detection ability or be buried in the
ground.
- pros: Very low false alarm rate, can be
put on top of any wall, very high chance of detecting real burglars.
- cons: Cannot be installed near high
voltage lines, radars, or airports.
E-field
This
proximity system can be installed on building perimeters, fences, and walls. It
also has the ability to be installed free standing on dedicated poles. The
system uses an electromagnetic field generator powering one wire, with another
sensing wire running parallel to it. Both wires run along the perimeter and are
usually installed about 800 millimetres apart. The sensing wire is connected to
a signal processor that analyses:
- amplitude change (mass of intruder),
- rate change (movement of intruder),
- preset disturbance time (time the
intruder is in the pattern).
These items
define the characteristics of an intruder and when all three are detected
simultaneously, an alarm signal is generated.
The barrier
can provide protection from the ground to about 4 metres of altitude. It is
usually configured in zones of about 200 metre lengths depending on the number
of sensor wires installed.
- pros: concealed as a buried form.
- cons: expensive, short zones which mean
more electronics (more money), high rate of false alarms as it cannot
distinguish a cat from a human. In reality it doesn't work that well, as
extreme weather causes false alarms.
Microwave
barriers
The
operation of a microwave barrier is very simple. This type of device produces
an electromagnetic beam using high frequency waves that pass from the
transmitter to the receiver, creating an invisible but sensitive wall of
protection. When the receiver detects a difference of condition within the beam
(and hence a possible intrusion), the system begins a detailed analysis of the
situation. If the system considers the signal a real intrusion, it provides an
alarm signal that can be treated in analog or digital form.
Microphonic
systems
Microphonic
based systems vary in design but each is generally based on the detection of an
intruder attempting to cut or climb over a chainwire fence. Usually the
microphonic detection systems are installed as sensor cables attached to rigid
chainwire fences, however some specialised versions of these systems can also
be installed as buried systems underground. Depending on the version selected,
it can be sensitive to different levels of noise or vibration. The system is
based on coaxial or electro-magnetic sensor cable with the controller having
the ability to differentiate between signals from the cable or chainwire being
cut, an intruder climbing the fence, or bad weather conditions.
The systems
are designed to detect and analyse incoming electronic signals received from
the sensor cable, and then to generate alarms from signals which exceed preset
conditions. The systems have adjustable electronics to permit installers to
change the sensitivity of the alarm detectors to the suit specific
environmental conditions. The tuning of the system is usually accomplished during
commissioning of the detection devices.
- pros: very cheap, very simple
configuration, easy to install.
- cons: some systems has a high rate of
false alarms because some of these sensors might be too sensitive.
Although systems using DSP (Digital Signal Processing) have largely
eliminated false alarms.
Taut
wire fence systems
A taut wire
perimeter security system is basically an independent screen of tensioned
tripwires usually mounted on a fence or wall. Alternatively, the screen can be
made so thick that there is no need for a supporting chainwire fence. These
systems are designed to detect any physical attempt to penetrate the barrier.
Taut wire systems can operate with a variety of switches or detectors that
sense movement at each end of the tensioned wires. These switches or detectors
can be a simple mechanical contact, static force transducer or an electronic
strain gauge. Unwanted alarms caused by animals and birds can be avoided by
adjusting the sensors to ignore objects that exert small amounts of pressure on
the wires. It should be noted that this type of system is vulnerable to
intruders digging under the fence. A concrete footing directly below the fence
is installed to prevent this type of attack.
- pros: low rate of false alarms, very
reliable sensors and high rate of detection.
- cons: Very expensive, complicated to
install and old technology.
Fibre
optic cable
A
fibre-optic cable can be used to detect intruders by measuring the difference
in the amount of light sent through the fibre core. If the cable is disturbed,
light will ‘leak’ out and the receiver unit will detect a difference in the
amount of light received. The cable can be attached directly to a chainwire
fence or bonded into a barbed steel tape that is used to protect the tops of
walls and fences. This type of barbed tape provides a good physical deterrent
as well as giving an immediate alarm if the tape is cut or severely distorted.
Other type’s works on the detection of change in polarization which is caused
by fiber position change.
- pros: very similar to the Microphonic
system, very simple configuration, easy to install. Can detect for
distances of several km on a single sensor.
- cons: high rate of false alarm or no
alarms at all for systems using light that leaks out of the optical fiber.
The polarization changing system is much more sensitive but false alarms
depend on the alarm processing.
H-field
This system
employs an electro-magnetic field disturbance principle based on two unshielded
(or ‘leaky’) coaxial cables buried about 10–15 cm deep and located at
about 2.1 metres apart. The transmitter emits continuous Radio Frequency (RF)
energy along one cable and the energy is received by the other cable. When the
change in field strength weakens due to the presence of an object and reaches a
pre-set lower threshold, an alarm condition is generated. The system is
unobtrusive when it has been installed correctly, however care must be taken to
ensure the surrounding soil offers good drainage in order to reduce nuisance
alarms.
- pros: concealed as a buried form.
- cons: affected by RF noise, high rate of
false alarms, hard to install.
Hooter
The hooters offered
are sophisticated, stylish and highly featured solution to external sounder
requirements.
The features are:
Easily mountable
Rugged strobe with panaromic lens
Sound output - 108 db - 113 db
Selectable timer
Dual ring mode
Alternating comfort Leds
Selectable sounder cut-off timer
System
connections
The trigger
signal from each sensor is transmitted to one or more control unit(s) either
through wires or wireless means (radio, line carrier, infrared). Wired systems
are convenient when sensors (such as PIRs, smoke detectors etc) require power
to operate correctly, however, they may be more costly to install. Entry-level
wired systems utilize a Star network topology, where the panel is at the center
logically, and all devices "home run" its wire back to the panel.
More complex panels use a Bus network topology where the wire basically is a
data loop around the perimeter of the facility, and has "drops" for
the sensor devices which must include a unique device identifier integrated
into the sensor device itself (e.g iD biscuit). Wired systems also have the
advantage, if wired properly, of being tamper-evident. Wireless systems, on the
other hand, often use battery-powered transmitters which are easier to install,
but may reduce the reliability of the system if the sensors are not supervised,
or if the batteries are not maintained. Depending on distance and construction
materials, one or more wireless repeaters may be required to get the signal
reliably back to the alarm panel. Hybrid systems utilize both wired and
wireless sensors to achieve the benefits of both. Transmitters, or sensors can
also be connected through the premises electrical circuits to transmit coded
signals to the control unit (line carrier). The control unit usually has a
separate channel or zone for burglar and fire sensors, and better systems have
a separate zone for every different sensor, as well as internal "trouble"
indicators (mains power loss, low battery, wire broken, etc).
Alarm
connection and monitoring
Depending
upon the application, the alarm output may be local, remote or a combination.
Local alarms do not include monitoring, though may include indoor and/or outdoor
sounders (e.g. motorized bell or electronic siren) and lights (e.g. strobe
light) which may be useful for signaling an evacuation notice for people during
fire alarms, or where one hopes to scare off an amateur burglar quickly.
However, with the widespread use of alarm systems (especially in cars), false
alarms are very frequent and many urbanites tend to ignore alarms rather than
investigating, let alone contacting the necessary authorities. In short, there
may be no response at all. In rural areas (e.g., where nobody will hear the
fire bell or burglar siren) lights or sounds may not make much difference
anyway, as the nearest responders could take so long to get there that nothing
can be done to avoid losses.
Remote alarm
systems are used to connect the control unit to a predetermined monitor of some
sort, and they come in many different configurations. High-end systems connect
to a central station or responder (eg. Police/ Fire/ Medical) via a direct
phone wire (or tamper-resistant fiber optic cable), and the alarm monitoring
includes not only the sensors, but also the communication wire itself. While
direct phone circuits are still available in some areas from phone companies,
because of their high cost they are becoming uncommon. Direct connections are
now most usually seen only in Federal, State, and Local Government buildings,
or on a school campus that has a dedicated security, police, fire, or emergency
medical department (in the UK communication is only possible to an Alarm
Receiving Centre - communication direct to the emergency services is not
permitted). More typical systems incorporate a digital telephone dialer unit
that will dial a central station (or some other location) via the Public
Switched Telephone Network (PSTN) and raise the alarm, either with a
synthesized voice or increasingly via an encoded message string that the
central station decodes. These may connect to the regular phone system on the
system side of the demarcation point, but typically connect on the customer
side ahead of all phones within the monitored premises so that the alarm system
can seize the line by cutting-off any active calls and call the monitoring
company if needed. Encoders can be programmed to indicate which specific sensor
was triggered, and monitors can show the physical location (or
"zone") of the sensor on a list or even a map of the protected
premises, which can make the resulting response more effective. For example, a
water-flow alarm, coupled with a flame detector in the same area is a more reliable
indication of an actual fire than just one or the other sensor indication by
itself. Many alarm panels are equipped with a backup dialer capability for use
when the primary PSTN circuit is not functioning. The redundant dialer may be
connected to a second phone line, or a specialized encoded cellular phone,
radio, or internet interface device to bypass the PSTN entirely, to thwart
intentional tampering with the phone line(s). Just the fact that someone
tampered with the line could trigger a supervisory alarm via the radio network,
giving early warning of an imminent problem (e.g., arson). In some cases a
remote building may not have PSTN phone service, and the cost of trenching and
running a direct line may be prohibitive. It is possible to use a wireless cellular
or radio device as the primary communication method.
Broadband
Alarm Monitoring
Increasing
deployment of voice over IP technology (VoIP) is driving the adoption of
broadband signaling for alarm reporting. Many sites requiring alarm
installations no longer have conventional telephone lines (POTS), and alarm
panels with conventional telephone dialer capability do not work reliably over
some types of VoIP service.
Legacy dial
up analog alarm panels or systems with serial/parallel data ports may be
migrated to broadband through the addition of an alarm server device which
converts telephone signaling signals or data port traffic to IP messages
suitable for broadband transmission. But the direct use of VoIP (POTS port on
premises terminal) to transport analog alarms without an alarm server device is
problematic as the audio codecs used throughout the entire network transmission
path cannot guarantee a suitable level of reliability or quality of service
acceptable for the application.
In response
to the changing public communications network, new alarm systems often can use
broadband signaling as a method of alarm transmission, and manufacturers are
including IP reporting capability directly in their alarm panel products. When
the Internet is used as a primary signaling method for critical security and
life safety applications, frequent supervision messages are configured to
overcome concerns about backup power for network equipment and signal delivery
time. But for typical applications, connectivity concerns are controlled by
normal supervision messages, sent daily or weekly.
Listen
In Alarm monitoring
Monitored
alarms and speaker phones allow for the central station to speak with the
homeowner and/or intruder. This may be beneficial to the owner for medical
emergencies. For actual break-ins, the speaker phones allow the central station
to urge the intruder to cease and desist as response units have been
dispatched.
Alarm
monitoring Services
The list of
services to be monitored at a Central Station has expanded over the past few
years to include: Access Control; CCTV Monitoring; Environmental Monitoring;
Intrusion Alarm Monitoring; Fire Alarm & Sprinkler Monitoring; Critical
Condition Monitoring; Medical Response Monitoring; Elevator Telephone
Monitoring; Hold-Up or Panic Alarm Monitoring; Duress Monitoring; Auto Dialer
tests; Open & Close Signal Supervision & Reporting; Exception Reports;
and PIN or Passcode Management. Increasingly, the Central Stations are making
this information available directly to end users via the internet and a secure
log-on to view and create custom reports on these events themselves.
Alarm
response
Depending
upon the zone triggered, number and sequence of zones, time of day, and other
factors, the monitoring center can automatically initiate various actions. They
might be instructed to call the ambulance, fire department or police department
immediately, or to first call the protected premises or property manager to try
to determine if the alarm is genuine. They could also start calling a list of
phone numbers provided by the customer to contact someone to go check on the
protected premises. Some zones may trigger a call to the local heating oil
company to go check on the system, or a call to the owner with details of which
room may be getting flooded. Some alarm systems are tied to video surveillance
systems so that current video of the intrusion area can be instantly displayed
on a remote monitor, not to mention recorded.
Access
control and bypass codes
To be
useful, an intrusion alarm system is deactivated or reconfigured when
authorized personnel are present. Authorization may be indicated in any number
of ways, often with keys or codes used at the control panel or a remote panel
near an entry. High-security alarms may require multiple codes, or a
fingerprint, badge, hand-geometry, retinal scan, encrypted response generator,
and other means that are deemed sufficiently secure for the purpose.
Failed
authorizations should result in an alarm or at least a timed lockout to prevent
"experimenting" with possible codes. Some systems can be configured
to permit deactivation of individual sensors or groups. Others can also be
programmed to bypass or ignore individual sensors (once or multiple times) and
leave the remainder of the system armed. This feature is useful for permitting
a single door to be opened and closed before the alarm is armed, or to permit a
person to leave, but not return. High-end systems allow multiple access codes,
and may even permit them to be used only once, or on particular days, or only
in combination with other users' codes (i.e., escorted). In any case, a remote
monitoring center should arrange an oral code to be provided by an authorized
person in case of false alarms, so the monitoring center can be assured that a
further alarm response is unnecessary. As with access codes, there can also be
a hierarchy of oral codes, say, for furnace repairperson to enter the kitchen
and basement sensor areas but not the silver vault in the butler's pantry.
There are also systems that permit a duress code to be entered and silence the
local alarm, but still trigger the remote alarm to summon the police to a
robbery.
Fire sensors
can be "isolated", meaning that when triggered, they will not trigger
the main alarm network. This is important when smoke and heat is intentionally
produced. The owners of buildings can be fined for generating False alarms that
waste the time of emergency personnel.
False
/ no alarms
System
reliability can be a problem when it causes nuisance alarms, false alarms, or
fails to alarm when called for. Nuisance alarms occur when an unintended event
evokes an alarm status by an otherwise properly working alarm system. A false
alarm also occurs when there is an alarm system malfunction that results in an
alarm state. In all three circumstances, the source of the problem should be
immediately found and fixed, so that responders will not lose confidence in the
alarm reports. It is easier to know when there are false alarms, because the
system is designed to react to that condition. Failure alarms are more
troublesome because they usually require periodic testing to make sure the
sensors are working and that the correct signals are getting through to the
monitor. Some systems are designed to detect problems internally, such as low
or dead batteries, loose connections, phone circuit trouble, etc. While earlier
nuisance alarms could be set off by small disturbances, like insects or pets,
newer model alarms have technology to measure the size/weight of the object
causing the disturbance, and thus are able to decide how serious the threat is,
which is especially useful in burglar alarms.
False-Alarm
Reduction
Home and
business owners can now choose a new type of keypad control panel designed to
help reduce false alarms.
Based on a standard
called CP-01-2000, developed by the American National Standards Institute
(ANSI) and Security Industry Association (SIA)) , the new generation of keypad
control panels takes aim at user error by building in extra precautions that
minimize unwarranted dispatch of emergency responders.
Some of the
features of CP-01 keypads include a progress annunciation function that emits a
different sound during the last 10 seconds of delay, which hastens exit from
the premises. Also, the exit time doubles if the user disables the pre-warning
feature.
Other
"rules" address failure to exit premises, which results in arming all
zones in Stay Mode and a one-time, automatic restart of exit delay. However, if
there is an exit error, an immediate local alarm will sound.
Cross
zoning reduces alarms
Cross zoning
is an innovative alarm-system strategy that does not require a new keypad.
Using multiple sensors to monitor activity in one area, advanced software
analyzes input from all the sources.
For example,
if a motion detector trips in one area, the signal is recorded and the
central-station monitor notifies the customer. A second alarm signal - received
in an adjacent zone in close time proximity, is the confirmation the
central-station monitor needs to request a dispatch immediately. This builds in
increased protection and a fail safe should a door blow open or a bird rattle
an exterior window.
Enhanced
Call Verification
Enhanced
Call Verification (ECV) helps reduce false dispatches while still protecting
citizens. ECV requires central station personnel to attempt to verify the alarm
activation by making a minimum of two phone calls to two different responsible
party telephone numbers before dispatching law enforcement to the scene.
The first
alarm-verification call goes to the location the alarm originated. If contact
with a person is not made a second call is placed to a different number. The
secondary number, best practices dictate, should be to a telephone that is
answered even after hours, preferably a cellular phone of a decision maker
authorized to request or bypass emergency response.
Video
verification
Video
verification documents a change in local conditions by using cameras to record
video signals or image snapshots. The source images can be sent over a
communication link, usually an Internet protocol (IP) network, to the central
station where monitors retrieve the images through proprietary software. The
information is then relayed to law-enforcement and recorded to an event file,
which can later be used as prosecution evidence.
An example
of how this system works is when a passive infrared or other sensor is
triggered a designated number of video frames from before and after the event
is sent to the central station.
A second
video solution can be incorporated into to a standard panel, which sends the
central station an alarm. When a signal is received, a trained monitoring
professional accesses the on-site digital video recorder (DVR) through an IP
link to determine the cause of the activation. For this type of system, the
camera input to the DVR reflects the alarm panel’s zones and partitioning,
which allows personnel to look for an alarm source in multiple areas.
SSA Integrate is Certified installer for Texecom Intrusion product in India.
