Access Code - Numeric or alpha numeric data which when correctly entered into a keypad, allows authorized entry into a controlled area with causing and alarm.
Access Control - Controlling access to a port of entry in physical area.
Access Point - Each means of entry into a controlled security area, consisting of a card reader, monitor switches and door latches/gates/turnstiles.  Access points are wired to an access control panel.
ADA - Americans with Disabilities Act.
Addressable Device - A component of a fire alarm system that has a specific identification and location. These devices allow the user to check the individual status of a device and control many other functions.
Addressable Intelligent Device - A signaling system data input device which, when communicating with a compatible control unit, may have its status individually identified by the control unit.
Addressable System - A system, which uses a signaling technique that, allows a control unit to identify a specific initiating device or group of devices by location.
AHJ - Authority Having Jurisdiction.  This might be the building inspector, fire code inspector, electrical inspector, etc.
Alarm Initiating Device - A device which when actuated, initiates an alarm. Such devices, dependant upon their type, may be operated manually or automatically. Automatic initiating devices may respond to smoke, heat, or waterflow, for example.
Alarm Input - An input connection to a security VCR or DVR that triggers the unit to start recording if the alarm is triggered.
Alarm Signal - A signal that is initiated by one of the devices on the system due to a fire emergency.
Ambient Light Level - The background of general light level of a given area.
Analog Initiating Device - A device that indicated different degrees of conditions, as compared to a conventional device that only indicated a on or off condition.
Analog Smoke Detector - A system smoke detector capable of communicating information regarding measured smoke level to a control unit. This type of detector is capable of sending signals to the control unit, which indicate the analog level of smoke within the detector. An analog smoke detector is typically used as part of an addressable system but differs from the Addressable Smoke Detector in that it is capable of communicating the level of smoke as well as its discrete address and its alarm and/or trouble condition.
Analog System - Most cameras used in CCTV applications are analog. Security VCRs, switchers, multiplexers and quads also are analog devices. Any CCTV system that consists of analog devices are considered analog systems. Compare to 'digital systems'.
Analog System - A fire alarm system which measures how much of a substance exists at an automatic initiating device contrasted with a conventional system, which can only determine whether the initiating device is on or off (in alarm or not in alarm). Measurements may include smoke density (percent obscuration), temperature, water level, air pressure, etc.
Angle of View - For security cameras, this refers to the angular range in degrees that you can focus the camera on without distorting the image. When focusing close up, you can generally see a wide angle of view. If the focus is distant, the angle of view is smaller or narrower. The lower the lens number (i.e. 2.9mm vs. 12mm) the wider the camera view. 
Annunciator - A unit containing information pertaining to the condition of system circuits and devices.
Anti-passback - A feature of an access control system which prevents successive use of one card to pass though any door, turnstile or portal in the same direction.  To attain this type of protection, a separate reader is required at each entry and exit.  Anti-passback prevents a card from being passed to another person for the purpose of unauthorized access.
Aperture - The opening of a lens which controls the amount of light let into the camera. The size of the aperture is controlled by the iris adjustment. By increasing the f stop number (f1.4, f1.8, f2.8, etc.) less light is permitted to pass into the camera.
Approved - Acceptable to the authority having jurisdiction. The National Fire Protection Association does not approve, inspect, or certify any installations, procedures, equipment, or materials; nor does it approve or evaluate testing laboratories. In determining the acceptability of installations, procedures, equipment, or materials, the authority having jurisdiction may base acceptance on compliance with NFPA or other appropriate standards. In the absence of such standards, said authority may require evidence of proper installation, procedure, or use. The authority having jurisdiction of an organization concerned with product evaluations that are in a position to determine compliance with appropriate standards for the current production of listed items.
Armor Dome Camera - These cameras are designed to resist vandalism by using a hi-impact reinforced polycarbonate dome casing.
Audible Notification Appliance - A notification appliance that alerts by the sense of hearing.
Audible Signal - The sound produced by a notification appliance such as a bell or horn when one of the initiating devices goes into alarm.
Audible Textual Notification Appliance - A notification appliance that conveys a stream of audible information. An example of an audible textual appliance is a speaker that reproduces a voice message.
Audit Trail - An historical record sequentially accounting for all activities with an access control system.  Such a record allows reconstruction and analysis of events during a given time period.
Authority Having Jurisdiction (AHJ) - The local organization that is responsible for approving a fire alarm system installation and plans.
Authorization Level - A pre-defined security rating which must be met before access to a protected area is granted.  Authorization Level is sometimes referred to as Access Level.
Auto White Balance - A feature on color cameras that constantly monitors the light and adjusts its color to maintain white areas.
Automatic Fire Alarm System - A system in which all or some of the circuits are actuated by automatic devices, such as fire detectors, smoke detectors, heat detectors, and flame detectors.
Automatic Fire Detector - A device designed to detect the presence of a fire signature and to initiate action. For the purpose of this code, automatic fire detectors are classified as follows:
Automatic Iris Lens - A lens in which the aperture automatically opens or closes to maintain proper light levels on the faceplate of the camera pickup device.
Back Focus - A mechanical adjustment in a camera that moves the imaging device relative to the lens to compensate for different back focal lengths of lenses. An important adjustment when a zoom lens is fitted.
Badging - The act of creating an ID card.  Photo badging includes a picture on the card.
Bandwidth - The range of frequencies a transmission line or channel can carry: the greater the bandwidth, the greater the information-carrying capacity of a channel. For a digital channel this is defined in bit/s.
Bar Code Card - A series of lines (or bars) printed on a card in a certain format which forms a code that is optically read by a reader
Bar Code Reader - A device that scans bar code information and transmits it to a central computer or control unit.  These units can take the form of readers, wands, or gun shaped scanners.
Bar Codes - A series of black lines (or bars) of various thickness that represents a code which is read through an optical reader and is interpreted by a computer of access control system.
Battery Backup - A standby energy source which serves a fixed and specified purposes in the event of a power failure.  Battery backups can be used to maintain data in memory, kept the system clock updated or operate card readers, door strikes, deadbolts and/ or magnetic locks if a power failure occurs.
Baud - The unit of speed of signal transmission, expressed in bits per second (bps).
Bimetallic - A sensing element comprised of two metals having different coefficients of thermal expansion arranged so that the effect is deflection in one direction when heated and in the opposite direction when cooled.
Biometric Access Control - A method of access verification in which persons seeking entry into a protected area are identified by their biometric parameters (fingerprints, hand geometry, etc.).
Bits-per-Second - The rate at which individual bits are transmitted across a communications link or circuit; written bit/s. One thousand bit/s is 1 Kbit/s, and one million bit/s is 1 Mbit/s.
Bullet Camera - A type of camera with a bullet like shape. Can be used inside or outside.
Byte - A group of eight binary data bits.
Card Reader - A device used to encode access information in, on, cards used for the purpose of gaining entry into protected areas.
CCD - Stands for "charge-coupled device". First invented in the 1970s, this technology uses a shift register combined with photodiodes to create the modern day imaging device. Used in cameras, scanners, fax machines, etc.
CCTV - Closed-circuit television.
Central Processing Unit (CPU) - An arrangement of circuitry using computer circuit techniques usually consisting of memory elements, signal processing circuitry, and a means to input and output data at very high speed.
Central Station Fire Alarm System - A system or group of systems in which the operations of circuits and devices are transmitted automatically to, recorded in, maintained by, and supervised from a listed central station having competent and experienced servers and operators who, upon receipt of a signal, take such action as required by this code. Such service is to be controlled and operated by a person, firm, or corporation whose business is the furnishing, maintaining, or monitoring of supervised fire alarm systems.
Central Station Service - The use of a system or a group of systems in which the operations of circuits and devices at a protected property are signaled to, recorded in, and supervised from a listed central station having competent and experienced operators who, upon receipt of a signal, take such action as required by NFPA 72, National Fire Alarm ode. Related activities at the protected property such as equipment installation, inspection, testing, maintenance, and runner service are the responsibility of the central station or a listed fire alarm service-local company. Central station service is controlled and operated by a person, firm, or corporation whose business is the furnishing of such contracted services or whose properties are the protected premises.
Central Station - A supervising station that is listed for central station service.
Class "A" Circuit - The wiring of initiating devices and notification appliances so that a single open or ground on the circuit does not cause the loss of the alarm system's function.
Class "B" Circuit - The wiring of initiating devices and notification circuits so that a single open or ground on the circuit does cause the loss of the alarm system's function.
Coded Signal - A signal pulsed in a prescribed code for each round of transmission. A minimum of three rounds and a minimum of three impulses are required for an alarm signal.
Coded - An audible or visible signal conveying several discrete bits or units of information. Notification signal examples are numbered strokes of an impact-type appliance and numbered flashes of a visible appliance.
Compression - Refers to taking an incoming signal or image, which can be analog or digital, and compressing the data so it can be stored or transmitted faster and using less resources. There are many different algorithms and techniques that are used to compress data.
Controller - This is a specialized device that manages access for specific doors and related devices.  It can be called a panel, control panel, or micro-controller depending on the manufacturer.
Covert - A covert application refers to a situation where you don't want the person to know that they are being watched or recorded. Also known as 'hidden' cameras.
Day/ Night Camera - "Day/Night Cameras" are regular cameras with an especially sensitive CCD chip that allows a good image to be captured in very low ambient lighting (regular lighting - not infrared).
Detector - A device suitable for connection to a circuit having a sensor that responds to a physical stimulus such as heat or smoke.
DHCP (Dynamic Host Configuration Protocol) - Address is dynamically assigned from a server that contains a pool of addresses.  The server leases the computer one of the available addresses for a specified amount of time.  Once the specified time has expired, the computer renews the lease or requests a new IP address.
Digital - There are two main ways of doing things electronically, analog or digital. The digital method is to consider a circuit either on or off. A digital voltage or signal refers to the discrete nature of digital voltage potentials in digital circuits. TTL (Bipolar Transistor-Transistor Logic) defines 0.0 Volts as a logic 0 or low, and 5.0 Volts as a logic 1 or high; These are single values for clarity - there are actually ranges of voltage potentials around 0.0V and 5.0V which are recognized as low and high logic levels, respectively.
Digital Alarm Communicator Receiver (DACR) - A component that receives signals from a communication transmitter (DACT). These signals contain information pertaining to the condition of the alarm system.
Digital Alarm Transmitter (DACT) - A component that transmits signals to a communication receiver (DACR). These signals contain information pertaining to the condition of the alarm system.
Digital Signal - An electronic signal where every value is expressed as a different binary code.
Digital System - CCTV systems are just lately coming into the digital age. Most security cameras are still analog. There are some digital cameras available but they are extremely expensive. Where digital technology is really making ground in CCTV is with digital video recorders (or DVRs). Any CCTV system that includes a DVR is considered a digital system.
Digital Video Recorder (DVR) - A system that allows the recording of video images in a digital form on one of may digital storage formats such as a computer hard disc, DigitalVHS, DV, DAT or DVD. It is acceptable in courts for evidential purposes.
Door Closure - A mechanical device that uses a stiff spring to automatically close and opened door.
Door Contact - A position locator that senses when the door is opened or fully closed.
Door Holder - An electromagnetic device used to hold a door open while energized. In the event of a fire, the door holder is de-energized and the door is allowed to close.
Download - The retrieval of information, with PC, from a peripheral devices such as a card reader or control pane.
Duplex - A duplex device can transmit data into and out of the electronic device at the same time. For example, a full duplex digital video recorder can continue capturing and recording images even while a different image is being displayed.
Electrical Conductivity - A line-type or spot-type sensing element whose resistance varies as a function of temperature.
Electrical Conductivity-Type Rate-of-Rise Detector - A line-type or spot-type sensing element whose resistance changes due to a change in temperature. The rate of change of resistance is monitored by associated control equipment, and an alarm is initiated when the rate of temperature increase exceeds a preset value.
Emergency Voice/Alarm Communications - Dedicated manual or automatic facilities for originating and distributing voice instructions, as well as alert and evacuation signals pertaining to a fire emergency, to the occupants of a building.
End-of-Line Device - A device used to terminate a supervised circuit. Typically a resistor or diode is installed in series at the end of a two-wire circuit to maintain supervision.
End-of-Line Relay - A relay used to supervise power, for example, supplied to a 4-wire smoke detector or power to an addressable device. The relay is installed within or adjacent to the last powered device on the circuit.
Erasable Programmable Read Only Memory (EPROM) - A nonvolatile semiconductor memory component whose contents may be erased, usually through exposure to ultraviolet light. EPROM's are used to store digital data.
Evacuation Signal - A distinctive signal intended to be recognized by the occupants as requiring evacuation of the building.
Evacuation - The withdrawal of occupants from a building. Evacuation does not include relocation of occupants within a building.
Existing - That which is already in existence on the date when the current edition of the Code goes into effect. See Building, Existing.
Exit Access - That portion of a means of egress that leads to an exit.
Exit Plan - A plan for the emergency evacuation of the premises.
Exit - That portion of a means of egress that is separated from all other spaces of the building or structure by construction or equipment as required in NFPA 101 5-1.3.2.1 to provide a protected way of travel to the exit discharge. Exits include exterior exit doors, exit passageways, horizontal exits, separated exit stairs, and separated exit ramps.
Fail Safe Lock - A lock, which is unlatched or unlocked when power failure occurs.  This type of lockset is locked when power is applied.
Fail Secure Lock - A type of lockset the automatically locks when a power failure occurs.  This type of lockset unlocks when power is applied.
Fault - An open, ground, or short condition on any lines(s) extending from a control unit, which could prevent normal operation.
Fiber Optics - Optical fiber (or "fiber optic") refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic wire or fiber. Optical fiber carries much more information than conventional copper wire and is in general not subject to electromagnetic interference and the need to retransmit signals. Unlike metallic-based systems, the dielectric nature of optical fiber makes it impossible to remotely detect the signal being transmitted within the cable. The only way to do so is by actually accessing the optical fiber itself.  Accessing the fiber requires intervention that is easily detectable by security surveillance. These circumstances make fiber extremely attractive to governmental bodies, banks, and others with major security concerns.
Fingerprint Reader - A high security biometrics access control device that identifies a person by his fingerprints.  After the finger is placed on a light sensitive plate, the print is read and compared to images stored in a computers' memory.  If the print matches one store in memory, access is granted.
Fire Alarm Control Panel - A component that receives inputs form initiating devices and sends outputs to notification appliances. This unit also supplies partial or all power to system components. This unit may incorporate a DACT to transmit signals to a DACR.
Fire Alarm System - A system or portion of a combination system consisting of components and circuits arranged to monitor and annunciate the status of fire alarm or supervisory signal-initiating devices and to initiate the appropriate response to those signals.
Fire-Gas Detector - A device that detects gases produced by a fire.
Firmware - The operating system for the controller held in a PROM or EPROM chip.
Fixed Temperature Detector - A device that responds when its operating element becomes heated to a predetermined level. The difference between the operating temperature of a fixed temperature device and the surrounding air temperature is proportional to the rate at which the temperature is rising and is commonly referred to as "thermal lag." The air temperature is always higher than the operating temperature of the device. Typical examples of fixed temperature-sensing elements follow.
Frame - The total area of the picture which is scanned while the picture signal is not blanked.
Frames Per Second (FPS) - In digital video applications, refers to the number of video images that can be captured, displayed, or recorded in a second. Also referred to as the 'frame rate' or 'refresh rate'.
Fusible Alloy - A sensing element of a special composition (eutectic) metal that melts rapidly at the rated temperature.
General Alarm - A term usually applied to the simultaneous operation of all audible alarm signals on a system to indicate the need to evacuate a building.
Ground Fault Detector - Detects the presence of a ground condition on system wiring.
Ground Fault - A condition in which the resistance between a conductor and ground reaches an unacceptably low level.
Heat Detector - A fire detector that senses heat produced by burning substances. Heat is the energy produced by combustion that causes substances to rise in temperature.
Heat-Sensitive Cable - A line-type device in which a sensing element comprises, in one type, two current-carrying wires separated by heat-sensitive insulation that softens at the rated temperature, thus allowing the wires to make electrical contact. In another type, a single wire is centered in a metallic tube, and the intervening space is filled with a substance that, at a critical temperature, becomes conductive, thus establishing electrical contact between the tube and the wire.
Horn - An audible notification appliance in which electrical energy is used to produce a sound by driving a device which imparts motion to a flexible component that vibrates at a nominal frequency.
Horn/Strobe - A combination audible and visible notification appliance, which operates as a horn and a strobe light, simultaneously. The horn produces a sound at a nominal frequency and the strobe light flashes at a predetermined rate.
Housing - Special covering or container to protect a camera from extreme temperatures or weather conditions.
ISDN (Integrated Services Digital Network) - Digital phone lines that allow transmission of video signals via fast scan at speeds of 128Kb/second; used with terminal adaptors.
Infrared - The region of the electromagnetic spectrum bounded by the long-wavelength extreme of the visible spectrum (approximately 0.7 m) and the shortest microwaves (approximately 0.1 mm).
Infrared Camera - Infrared cameras (aka night vision cameras) have special infrared lights installed around the perimeter of the camera lens. This provides special light that the camera uses to capture a good picture even in total darkness.
Infrared Reader - A card reader that used an infrared light source to read information encoded in an access control card.  This reader is an optical technology, and is based on an optical density principal.
Initiating Device - A component such as a smoke detector or pull station that transmits an alarm signal to a control panel.
Initiating Device Circuit - A circuit to which initiating devices are connected.
Integrated System - A computer-based control system listed for use as a fire alarm system, in which certain components are common to non-fire monitoring and control functions.
Intelligent System - A system using analog devices communicating with a control unit that individually monitors the value or status reported by the analog sensors and makes the normal, alarm, or trouble decisions.
Ionization Smoke Detection - The principle of using a small amount of radioactive material to ionize the air between two differentially charged electrodes to sense the presence of smoke particles. Smoke particles entering the ionization volume decrease the conductance of the air by reducing ion mobility. The reduced conductance signal is processed and used to convey an alarm condition when it meets preset criteria. Ionization smoke detection is more responsive to invisible particles (smaller than 1 micron in size) produced by most flaming fires. It is somewhat less responsive to the larger particles typical of most smoldering fire. Smoke detectors utilizing the ionization principle are usually of the spot type.
IP Address (Static and DHCP) - Identifies a particular computer on a network to other computers.  An IP address is similar to your home address.  In a neighborhood, each house has a unique address; on a network each computer must have a unique address.  There are two types of IP addresses - static and DHCP.
Iris - The iris (on some lenses) controls how much light is let into the camera lens.
JEPG (JPG) - Pronounced "jay-peg" and stands for "Joint Photographic Experts Group" who designed the standard. This is a standard way of compressing images which works particularly well for photographic images (as opposed to graphic art).
LAN - Local Area Network; multiple computers connected together to share information.  Think of a LAN as a neighborhood within a city.
Lens - The lens of the camera determines the angle of view and the focus of the captured image. There are many different lens options.
Light Emitting Diode (LED) - A diode that emits visible light when current is applied. LED's are used as single element visible indicators or as multiple-segment displays.
Liquid Crystal Display (LCD) - An arrangement of individual segments used to display information. Each segment becomes transparent or opaque as electric current is applied or removed from each segment.
Liquid Expansion - A sensing element comprising a liquid capable of marked expansion in volume in response to temperature increase.
Listed - Equipment, materials, or services included in a list published by an organization acceptable to the authority having jurisdiction and concerned with evaluation of products or services that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services and whose listing states either that the equipment, material, or service meets identified standards or has been tested and found suitable for a specified purpose. The means for identifying listed equipment may vary for each organization concerned with product evaluation, some of which do not recognize equipment as listed unless it is also labels. The authority having jurisdiction should utilize the system employed by the listing organization to identify a listed product.
Local Fire Alarm System - A local system sounding an alarm at the protected premises as a result of the manual operation of a fire alarm box or the operation of protection equipment or systems, such as water flowing in a sprinkler system, the discharge of carbon dioxide, the detection of smoke, or the detection of heat.
Loss of Power - The reduction of available voltage at the load below the point at which equipment can function as designed.
Low Light - Refers to very dim lighting, even 'normal' darkness. Complete darkness is 0 lux. Infrared cameras work well in very low light conditions.
Lux - Refers to the amount of light required for a camera to capture a good image.
Magnetic Lock - A type of door lock consisting of an electromagnet and strike plate.  The electromagnetic is mounted on the door frame, opposite the strike plate, which is mounted on the door.  When power is applied, the strength of the magnet secures the door.
Magnetic Stripe Card - A type of access control card with a data encoded strip of magnetic material.
Maintenance - Repair service, including periodic inspections and tests, required to keep the fire alarm system and its component parts in an operative condition at all times, together with replacement of the system or its components when they become undependable or inoperable for any reason.
Manual Fire Alarm Box - A manually operated device used to initiate an alarm signal.
Monitor - Security monitors are used to display the images from your cameras (or captured on your recording device). There are two basic kinds used today in CCTV applications. Analog or composite video monitors are used to display images in analog systems. They are just like a TV screen without the TV receiver. These are the monitors we have for sale on our site. Digital or VGA monitors (just like on your computer) are used with digital devices like the Digital Video Recorders.
Motion Detection - Refers to the feature in some VCRs and DVRs to only record video if something in the image moves or changes. Therefore you don't have to look through hours of taped video looking for something to happen. It also saves a lot of space on the tape or hard drive.
Mounting Bracket - Various different kinds of mounting brackets are used to install cameras to the wall or ceiling.
MPEG (MPG) - Pronounced "em-peg" and stands for "Motion Picture Experts Group" who designed the standard. This is a standard way of compressing audio and video files. (It's also the technology behind the now world-famous MP3 music files.)
MPS (Main Power Supply) - The main power supply of a control unit provides all of the necessary power to operate the control unit plus the power required to operate automatic initiating devices and notification appliances and annunciators.
Multiple Station Alarm Device - Two or more single station alarm devices that can be interconnected so that actuation of one causes all integral or separate audible alarms to operate. It also can consist of one single station alarm device having connections to other detectors or to a manual fire alarm box.
Multiple Station Alarm - A single station alarm capable of being interconnected to one or more additional alarms so that the actuation of one causes the appropriate alarm signal to operate in all interconnected alarms.
Multiplexed Initiating Device Loop - A circuit that connects the transponder or digital alarm communicator transmitter (DACT) to a number of initiating device interfaces.
Multiplexer - A device that can accept a number of camera inputs and almost simultaneously display them on a single monitor and/ or record them. Multiplexers can also be used to transmit multiple cameras over the same transmission medium.
Multiplexing - A signaling method characterized by simultaneous or sequential transmission, or both, and reception of multiple signals on a signaling line circuit, a transmission channel, or a communications channel, including means for positively identifying each signal.
Network - Computers connected to share information.  Think of a network as a city and the computers as houses within the city.  Two types of networks are LAN and WAN.
NFPA - National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02269.
Node - A connection point on a network cable.
Noncoded - An audible or visible signal conveying one discrete bit of information.
Notification Appliance Circuit (NAC) - A circuit or path directly connected to a notification appliance(s).
Notification Appliance - A fire alarm system component such as a bell, horn, speaker, light, or text display that provides audible, tactile, or visible outputs or any combination thereof.
Notification Zone - An area covered by notification appliances that are activated simultaneously.
Nuisance Alarm - Any alarm caused by mechanical failure, malfunction, improper installation, or lack of proper maintenance, or any alarm activated by a cause that cannot be determined.
Occupancy - The purpose for which a building or portion thereof is used or intended to be used.
Occupant Load - The total number of persons that might occupy a building or portion thereof at any one time.
Olfactory Notification Appliance - A notification appliance that alerts by the sense of smell.
Other Fire Detectors - Devices that detect a phenomenon other than heat, smoke, flame, or gases produced by a flame.
Outdoor Camera - Come in special weatherproof housings that allow them to stand up in tough weather and temperature conditions.
Panic Bar - A quick release door mounted exit bar permitting fast opening in cases of fire of emergency situation.  Also called a crash bar or exit device.
Pan-Tilt-Zoom (PTZ) - PTZ cameras allow you to adjust the position ('pan' is side-to-side, 'tilt' is up-and-down) and focus ('zoom') of the camera using a remote controller. Due to this added functionality, these cameras tend to cost much more than non-PTZ cameras.
Photoelectric Light Obscuration Smoke Detection - The principle of utilizing a light source and a photosensitive sensor onto which the principal portion of the source emissions is focused. When smoke particles enter the light path, some of the light is scattered and some is absorbed, thereby reducing the light reaching the receiving sensor. The light reduction signal is processed and used to convey an alarm condition when it meets preset criteria. The response of photoelectric light obscuration smoke detectors is usually not affected by the color of smoke. Smoke detectors utilizing the light obscuration principle are usually of the line type. These detectors are commonly refereed to as "projected beam smoke detectors."
Photoelectric Light-Scattering Smoke Detection - The principle of utilizing a light source and a photosensitive sensor arranged in a manner so that the rays from the light source do not normally fall onto the photosensitive sensor. When smoke particles enter the light path, some of the light is scattered by reflection and refraction onto the sensor. The light signal is processed and used to convey an alarm condition when it meets preset criteria. Photoelectric light-scattering smoke detection is more responsive to visible particles (larger than 1 micron in size) produced by most smoldering fires. It is somewhat less responsive to the smaller particles typical of most flaming fires.
PIN - Personal Identification Number
Pin-hole Camera - Pin-hole cameras have a very small lens that can see through a small hole. These types of cameras are used in covert applications. A disadvantage of pin-hole cameras is that they require more lighting than normal cameras to capture a good clear picture.
Pixel - Short for 'picture element'.  Pixels are the tiny dots of information that make up a digital image.  The more pixels there are on the cameras image sensor (CCD), the higher the image resolution will be.  The higher the resolution, the clearer an enlarged picture can print.
Plenum - The space that moves environmental air throughout a building.  Plenum areas are generally in the ceiling, under false floor, or in the HVAC system.  These areas require that devices within them be made of non-flammable and non-smoking materials (plenum rated).
NOTE: The definition of plenum is not intended to apply to the space above a suspended ceiling that is used for environmental air referred to in NFPA 70-2002 300.22(C).
Plenum - An air compartment or chamber to which one or more ducts are connected and that forms part of an air distribution system.
Power Limited Circuit - A circuit that limits power to the load inherently or by overcurrent protection.
Power Supply - All cctv devices need power of some sort. Each device has its own power requirements (usually 12 volts with a minimum amperage). The power coming out of the wall (in the US) is 110 to 120 AC. The power supply converts the AC power to DC power and will adjust it to a specified amperage. The power supply should be included with each item - you don't have to buy these separately.
Power Supply - A source of electrical operating power including the circuits and terminations connecting it to the dependent system components.
Projected Beam-Type Detector - A type of photoelectric light obscuration smoke detector wherein the beam spans the protected area.
Protected Premises (Local) Control Unit (Panel) - A control unit that serves the protected premises or a portion of the protected premises and indicated the alarm via notification appliances inside the protected premises.
Protected Premises (Local) Fire Alarm System - A protected premises system that sounds an alarm at the protected premises as the result of the manual operation of a fire alarm box or the operation of protection equipment or system, such as water flowing in a sprinkler system, the discharge of carbon dioxide, the detection of smoke, or the detection of heat.
Protected Premises - The physical location protected by a fire alarm system.
Proximity Card - A radio frequency based card technology that utilizes a microcircuit which, when presented to a proximity reader, activated the card's circuitry, thus transmitting the data stored in the card.
Radiant Energy-Sensing Fire Detector - A device that detects radiant energy (such as ultraviolet, visible, or infrared) that is emitted as a product of combustion reaction and obeys the laws of optics.
Rate Compensation Detector - A device that responds when the temperature of the air surrounding the device reaches a predetermined level, regardless of the rate of temperature rise. A typical example is a spot-type detector with a tubular casing of a metal that tends to expand lengthwise as it is heated and an associated contact mechanism that closes at a certain point in the elongation. A second metallic element inside the tube exerts an opposing force on the contacts, tending to hold them open. The forces are balanced in such a way that, on a slow rate-of-temperature rise, there is more time for heat to penetrate to the inner element, which inhibits contact closure until the total device has been heated to its rated temperature level. However, on a fast rate-of-temperature rise, there is not as much time for heat to penetrate to the inner element, which exerts less of an inhibiting effect so that contact closure is achieved when the total device has been heated to a lower temperature. This, in effect, compensates for thermal lag.
Rate-of-Rise Detector - A device that responds when the temperature rises at a rate exceeding a predetermined value. Typical examples of rate-of-rise detectors follow Pneumatic Rate-of Rise Tubing. A line-type detector comprising small-diameter tubing, usually copper, that is installed on the ceiling or high on the walls throughout the protected area. The tubing is terminated in a detector unit containing diaphragms and associated contacts set to actuate at a predetermined pressure. The system is sealed except for calibrated vents that compensate for normal changes in temperature.
Real-time Recording - In digital video applications, 30 frames per second per camera looks just like real-time. There is no hesitation or jerkiness in the video.  Most systems are advertised as 30 fps, but usually this means 30 fps divided by the number of cameras on the system (i.e. if 16 cameras are on the system, the fps per camera would be 1.8 fps per camera).  To get 30 fps per camera you would need a 480 fps system, which is available through OEP.
Remote Surveillance - The ability to view your cameras from a remote location. Information is transmitted via phone line, internet, LAN, WAN, or DSL.
Resolution - Refers to how much detail can be captured on a camera or displayed on a monitor. Cameras typically capture about 380 horizontal lines of resolution. High resolution cameras may capture 480 lines of resolution or more. The higher the resolution, the more detail that can be captured in a picture. The monitors and recording devices can generally handle at least as much resolution as the cameras can capture.
Retard (Adjustable) Waterflow Switches - An adjustable time delay mechanism in a waterflow switch located between the paddle-operated stem and the initiating contacts. This type of switch is designed to prevent brief water flow surges due to water hammer and/or pressure variations from causing an unwanted alarm signal.
Retina Reader - A biometric based access control device that scans the blood vessel pattern in a person retina and compares it with stored images before granting or denying access.
Reverse Polarity Interface - A connection from a control unit to a supervising station which operates using polarity reversal to signal an alarm, supervisory, or trouble signals.
Shielded Cable - A special metallic foil, tape, or wire braid, that covers the entire set of conductors in a single cable.  It serves to protect the cable against EMI or RFI (Electromagnetic or Radio Frequency Interference).
Siamese Cable - This type of cable combines the power wire with the video wire. Connectors need to be added each end of the cable. This type of cable is used when you need to run distances longer than 100 ft with a digital system, or more than 400 ft. with an analog system. The RG59 siamese cable can be run reliably up to 1000 ft.  The RG6 siamese cable can take longer runs.
Smart Card - An identification card containing an integrated circuit allowing it to receive and store data, which gives it limited microprocessor intelligence.
Smart Search - Is a feature that allows you to search for changes in a particular areas of an image over time. For example, if a wallet was stolen off of a table, you could go to a point on the video where the wallet is there, draw a virtual box around that area, then search the video recording for changes to that particular area. This would allow you to locate the exact point on the video where the wallet was removed.
Smoke Detector - A device that detects visible or invisible particles of combustion.
Spot Type Detector - A component that detects only in a particular location.
Spot-Type Pneumatic Rate-of-Rise Detector - A device consisting of an air chamber, a diaphragm, contacts, and a compensating vent in a single enclosure. The principle of operation is the same as that described for pneumatic rate-of-rise tubing.
Standby Battery - A battery referred to as the secondary power supply, which is kept charged by the fire alarm control unit or by a separate battery charger. When primary (AC) power fails, the battery supplies power for a limited time. The time required for a standby battery to operate the fire alarm system is defined by NFPA 72-1996 1-5.2.6.
Static Address - Where someone physically connects to a computer and defines the IP address for that computer.  A static address does not change unless someone physically changes it.
Supervision - The term supervised refers to monitoring of the circuit, switch, or device in such a manner that a trouble signal is received when a fault that would prevent normal operation of the system occurs.
Supervisory Service - The service required to monitor performance of guard tours and the operative condition of fixed suppression systems or other systems for the protection of life and property.
Supervisory Signal - A signal indicating the need of action in connection with the supervision of guard tours, the fire sup