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Common Security Terms


We always try to keep everything as jargon free as we can however sometimes this just isn’t possible, below is a list of common security related terms and their meanings.


Access Control
Access Control is a type of physical security which can deny or grant access to personnel based on their level of authorised security clearance.
A person or organisation officially recognised by an institution or governing body in having achieved a particular standard of service, knowledge or expertise.
AGC (Automatic Gain Control)
A process of control that automatically adjusts the video quality in low-light conditions.
AI (Artificial Intelligence)
AI refers to intelligence which is used in machines to perform tasks in a way that a human would. This can include tasks such as visual perception, facial recognition and problem-solving.
An alarm is an audible or visual system/device that gives off a signal usually to alarm someone of something.
Alarm Monitoring
This is a form of communication between a central system and your security system. The central system can be notified from your home system if there was an emergency such as a burglary or attempted burglary. Once this signal has been sent to the central system, authorities can therefore be notified depending on the situation.
Analogue (Analog)
Continuously Variable numerical values such as current and voltage. The CCD camera produces analogue video signals.
Angle of View
The angle that a video camera lens can portray on a monitor. Such as a Diagonal Angle, Horizontal Angle and Vertical Angle. These are commonly described in degrees.
The Automatic Number Plate Recognition process consists of cameras that can read number plates of passing vehicles to check and record them into a database system.
The opening/hole in which light can travel through. Moreover, the aperture or focal length can determine the angle of a bundle of rays that come to focus in an image plane within an optical system.
An Address Resolution Protocol is a process used for mapping an IP address to a physical machine address.
Aspect Ratio
The ratio between the vertical to the horizontal image size. The ratio 4:3 is referred to as the PAL standard.
Aspherical Lens
A lens which is designed with a non-spherical shape so that it is able to pass high amounts of light, or decrease the barrel distortion on wide-angle lenses.
A loss or decrease in a signal, which is commonly measured in decibels.
ATEX (ATmospheres Explosible)
An international standard and rating given to products (such as CCTV cameras) which are explosion proof.
Audible Warning
An audible warning is a type of alarm signal which produces an audible warning sound.
This is a process which automatically selects the correct termination which is dependent on whether a video output is connected or not.
Auto White Balance
An AWB automatically adjusts a colour camera's colour to maintain white areas.
Auto-focus Lens
Automatically adjusts the focus on a lens, from the surrounding scene and keeps a moving object in focus.
Automatic Iris (Auto-Iris)
A device in a lens that adjusts to changing levels of light. The iris diaphragm can open or close the aperture, in order to control the amount of light coming through that lens.
Automatic Level Control
ALC allows the auto-iris to either take bright spots more into consideration by bringing out detail in bright areas. It can also bring out the detail in shadows.


Black Light Compensation (BLC)
BLC compensates electronically for high background lighting to give higher definition detail, which would normally be silhouetted.
The capacity of data that can be transmitted within a fixed amount of time. For digital and analog devices, the bandwidth is usually measured differently.
A unit of measurement that denotes the number of bits that can be transmitted per second. For example, if a modem is rated at 9600 baud it is capable of transmitting data at a rate of 9600 bits per second.
Bell Boxes
Bell Boxes are a part of the intruder alarm system which can deter criminals by producing an audible and visual warning in the event of the alarm being triggered.
BGU (Break Glass Unit)
As a common fire system procedure, a BGU is used on all fire systems in order to raise the alarm manually by breaking the glass or plastic that covers the unit. You usually will find a BGU at exits, fire escapes, landings and high-risk areas.
A bit is known as a ‘Binary Digit’. This is known as the smallest unit of data in a computer.
The process whereby the beam in a CRT (Cathode Ray Tube) is cut off during the retrace period.
A Bayonet Neil-Concelman or British Naval Connector that is widely used in the CCTV industry. These are usually in the form of a coaxial cable
BORIS is ClearView’s online passive fire protection portal. It can log client installations that are taking place on site, with photographic evidence of the installation and the locations. Clients must have their own login so they can access their reports, updates and real-time data. BORIS is for our Passive Fire Protection (Fire Stopping) installations only.
Bits Per Second is the unit used for measuring line speed, the number of information units transmitted per second.
Brightness Control
The manual bias control on a cathode ray tube or other display device that controls the average brightness and the contrast of a picture
A Byte is a unit of data that is ‘eight bits long’ and is used by computers to represent characters such as numbers, letters and symbols.
Bullet Camera
A bullet camera is a type of small camera used in security applications which can easily be altered to point in a different direction.


An industry standard for lens mounting. C-Mount is 1-inch diameter with 32 threads per inch. A C-Mount lens needs a ‘C-ring’ when it is mounted on a CS-Mount camera.
Cable Networks
A network of cables that are used to connect and transfer data across devices such as routers, computers, and storage area networks.
Camera Format
A video camera's CCD chips format, such as 2/3", 1/3", 1/4" etc.
Camera Sensor
A camera sensor is referred to as a video image sensor which is usually in the form of a CCD or C-MOS chip.
CCD stands for a Charge Coupled Device. This divide is an integrated circuit which contains an array of linked capacitors.
International Radio Consultative Committee; has made the technical recommendation for the European 625 line standard for video signals.
Stands for the ‘Closed Circuit Television Manufacturers Association’.
Closed Circuit Television or commonly referred to as CCTV is a television system that sends signals to one or more monitors instead of broadcasting over a public network, this then makes it a closed-circuit. A standard CCTV system will normally include a CCTV camera (for capturing video), transmitters and receivers (to transfer the video from the source to where it is recorded), a recording system (for video playback), and a monitor (for video monitoring). CCTV systems are primarily used for security purposes inside and outside buildings. However, they can also be used for specialist applications such as mobile police use and interrogation.
The Contractors Health and Safety Assessment Scheme or otherwise referred to as CHAS allows contractors to demonstrate whether they meet health and safety requirements to new and existing clients.
‘Complementary - Metal Oxide Semiconductor’ is a video image sensor chip that produces lower quality images than images from CCD chips.
Coaxial Cable
A cable that can carry a wide range of frequencies with very low signal loss. It consists of a metallic shield with a single wire placed along the center of a shield and isolated from the shield by an insulator.
Colour Saturation
The degree of mixture of a color and white. High saturation means little or no white.
ColorVu is a technology by leading security manufacturer Hikvision which enables cameras to produce high colour videos in dimly lit environments.
Composite Video Signal
A combination of signals in a television transmission. The picture signal, blanking signal, and vertical/horizontal synchronizing signals are all combined.
Covert cameras are deployed and utilised for discreet surveillance.
The Cathode Ray Tube is the vacuum tube part of a monitor or television. A CRT can modulate, and accelerate electron beams onto screens to create images.
An industry standard for lens mounting. CS-Mount is 1 inch diameter with 32 threads per inch. A C-Mount lens needs a C-ring when it is mounted at a CS-Mount camera.


Day/Night View
A CCTV camera with Day/Night View can operate and function during daylight hours and during the night time when light levels are low.
Decodes multiplexed live or recorded video to allow pictures to be viewed in full or multi-screen format.
Decibel (Db)
Is the power or voltage ratio of two signals. It can be used to express the ratio of one value of a power to another on a logarithmic scale.
Multi-wire cable with DIN connectors at both ends. Usually has 5 or 6 inner wires. Different diameter and configuration from maker to maker.
DIP Switches
Dual Interface Poll switches usually allow you to change the configuration of a circuit board to suit your application.
Dome CCTV/security cameras are in the form of a dome shape. Moreover, due to its shape, it can deter crime due to not being able to see in which direction the camera is pointing.
A Digital Subscriber Line is a type of technology which brings higher-bandwidth information to homes and businesses over ordinary copper telephone lines.
A DVR or Digital Video Recorder is an electronic device which can record video in a digital format, onto different devices. Such as an SD card, USB flash drive or disk drive.
Dwell Time
The length of time a switcher displays one camera before sequencing to the next.


Electronic Industries Association is the American standard for B/W camera systems.
Electronic Light Control compensates for moderate light changes in indoor applications without the use of auto iris lenses. Select this mode when a fixed iris lens or manual iris lens is used.
Electronic Gates
An electronic gate is a gate that is wired up to an electronic mechanism and system, usually with a control panel to allow automated access into a property.
Electronic Shutter
Compensates for moderate light changes in indoor applications without the use of auto iris lenses
Emergency Lighting
Emergency Lighting is activated when the main power supply is cut and the usual supply fails to respond. Emergency lighting is an important security feature to install, as without it could lead to physical danger and sudden darkness.
This is the most widely installed Local Area Network (LAN) technology. The most common Ethernet system can provide transmission speeds of up to 100 Megabits per second.
Extended Infrared or otherwise referred to as EXIR is a technology that is designed to improve the visibility of security cameras in dark environments.


f-number (f-stop)
Is the optical or lens speed. Smaller f-number means a faster lens.
Fibre-Optic Cable
One of the video transmission ways, being used for a long distance transmission up to miles.
One video frame is composed of two fields; one field consists of the odd numbered lines in the frame and the other field consists of the even numbered lines.
Field of View
FOV is the width, height or diameter of a scene to be monitored. Usually determined by the focal length of a lens, the sensor format and the distance to the objects.
Fire Alarm
This is a system which connects a number of devices to work together in order to detect and warn people when there is a fire present. This alarm can warn people through visual and audio alerts when fire, smoke, and carbon monoxide have been detected.
Fire Batt
A fire batt is a mineral fibre board that allows up to 4 hours of fire and smoke protection. They are usually coated on both sides with an intumescent mastic.
Fire Extinguisher
A fire extinguisher is a fire apparatus that can be portable, with the sole purpose of extinguishing a fire and putting it out. It can do this by releasing a substance that can deprive the flame of oxygen, cool down materials that are on fire as well as interfering with chemical reactions.
Fire Risk Assessment
An assessment of a building to inspect and evaluate the risk of fire and potential fire hazards. The assessment assesses the likelihood of a fire starting, the cause of that fire and therefore the harm that could occur to those around the premises. It also makes recommendations to improve the fire safety of the building and to ensure compliance with fire regulations.
Fire Stopping
Fire stopping is part of the passive fire protection for a building and is the practice of reinstating fire compartmentation or barriers which have been penetrated.
Certain cameras come equipped with a ‘fisheye lens’. This type of lens has an ultra wide angle lens which produces a ‘visual distortion’ in order to create a wide view/shot. They achieve an extremely wide angle of view, more so than other types of camera lenses.
The most common type of CCTV cameras are fixed cameras. These can provide several different views that can be controlled from a control centre or remotely.
Flash Memory
Flash RAM (Random Access Memory) is a type of constantly powered nonvolatile memory, that can be erased and reprogrammed in units of memory called blocks.
Focal Length
The FL is the distance from the center of a lens (or, the secondary principal point, if it has) to the focal point (sensor). The longer the focal length, the narrower is the angle of view.
A whole video image; is composed of two interlaced fields. A CCD chip produces 30 frames per second at NTSC system and 25 frames at PAL.
A File Transfer Protocol is a way to exchange files between computers on the Internet.


Gamma is a degree of contrast in a video image between the output magnitude and the input magnitude.
One gigabyte is equal to 1,000 megabytes and precedes the terabyte unit of measurement.
Genlock or otherwise known as generator locking is a technique where the video output of one source is used to put together other picture sources and synchronise them. It can adjust the frequency of an internal sync to external data.
A shadowy or weak image in the received picture, offset to either the right or to the left of the primary image.


A H264 provides high-quality images by using an efficient code and a minimal amount of bandwidth (compression standard - old standard).
The High Efficiency Video Coding H265 is a widely used advanced video compression coding. It is the current standard but more efficient.
Hard Drive
Hard drives are a component of hardware with the sole purpose of storing digital content and data. It can store music, videos, images, documents, applications and more.
A camera that is HD 2MP is a camera with 2 megapixel and high-definition vision. These cameras would be used for general household CCTV monitoring.
Heat Mapping
Heat mapping is a data collection method used by video analytics software which highlights areas on CCTV footage where there is a high volume of traffic. This can be used for business intelligence to identify popular products and consumer behaviours.
As a network product, a hub may include a group of modem cards for dial-in users, a gateway card for connections to a Local Area Network (LAN), and a connection to a line.
Hz (Hertz)
Hertz frequency is a rate at which a current changes direction per second. An international unit of measure which ‘1 Hz is equal to 1 cycle per second’.


Is an electrical characteristic of a system or component, expressed in ohms. CCTV industry has standardized 75-ohm impedance.
Infrared (IR) Light
Infrared is an invisible light beyond the 750 nanometers (red end of the visible lights).
Is an Internal sync mode that sets to internal 2:1 interlace.
An intercom device allows 2 way communication usually to identify a person before allowing them access to a particular area.
Integrated Systems
This is the process of integrating both virtual and physical components of a system within an organisation. Components can consist of machine systems or hardware.
Intruder Alarm
Intruder alarms can detect an unauthorised entry into rooms, buildings or sites and trigger a response such as an alarm in order to alert a system or person.
Internet Protocol is a set of rules to send and receive messages at the Internet address level.
An adjustable opto-mechanical aperture built into a camera that controls the amount of lights coming through the lens.
An Integrated Service Digital Network is a set of standards for digital transmissions over ordinary telephone copper wire.


A Joint Photographic Experts Group is a graphic image file or an image compression algorithm.


A kilobyte is the smallest unit of measurement but is greater than a byte.
Kilobits per second (thousands of bits per second) is a measure of the amount of data which can flow in a given time; i.e. a measure of bandwidth.
Keyholding is a security service that consists of a security firm that has been contracted to a company to hold a set of keys to protect their premises and respond to any intruder alarm activations.


A Local Area Network is a group of computers and associated devices that share a common communications line.
An LED or otherwise referred to as a light-emitting diode is a semiconductor light source that emits light when a type of current flows through it.
Lens Mount
A lens mount is the area where a lens is mounted. There are two different types; C- or CS-Mount.
Lens Speed
Optical speed, expressed by f-number. Smaller f-number means a faster lens.
Linux or UNIX-like operating system is a very efficient and fast-performing system. It is the most-used open source operating system.
LUX is a measurement of Lumens per Square Meter. This is the unit of illumination amount.


A megabyte is a multiple of the unit byte for reference of digital information. The recommended unit symbol if referred to MB. One MB is one million bytes of information.
Mbps or Megabits per second is a measure of bandwidth. Most commonly used for Internet speed and broadband services.
Megapixel is a term used to describe one million pixels. The resolution of many security cameras are measured in megapixels.
Multi-wire cable with Mini-DIN connectors at both ends. Usually has 4 inner wires.
A security camera monitor is used to display the live feeds of all CCTV cameras.
Monochrome Signal
A monochromatic object or image which reflects colors in shades of limited colors/hues or otherwise known as a ‘Black and White Signal’.
A Metal-oxide Semiconductor is one of the video image chips like CCD, but it produces lower quality video.
Motorised Lens
A camera lens equipped with a small electric motor that enables focusing lens, opening or closing the iris diaphragm, or changing the focal length.
Moving Picture Experts Group. A standard for a digital video & audio compression.
Combines two or more video/audio signals into one channel. Usually accepts 10 or 16 video inputs and displays them in various formats.


Refers to any undesired signals that corrupt the original video signals and may reduce the image quality.
A National Television System Committee formulates standards for American color television system. The NTSC system has 525 horizontal scan lines and 30 frames per second.
NVR (for IP cameras)
Network Video Recorder are a part of IP CCTV systems which records and stores the footage from the CCTV Cameras. This allows the user to access previously recorded footage.


A Phase Alternating Line or PAL system is a color television system which is used in Europe, Australia, parts of Africa as well as the Middle East. It has 625 horizontal scan lines and 25 frames per second.
A rotating or scanning CCTV camera which moves sideways in order to view an area in a horizontal direction.
Panic Alarm
A panic alarm is an electronic device that can be used by a person to raise the alarm in an emergency situation. For example, this situation could be a threat to a person’s property or to themselves.
Pan and Tilt
A type of CCTV camera which mounts a device that allows movement in both sideways and up or down.
Passive Fire Protection
Passive Fire Protection is a structure of all fire safety components within a building or premises. This protection slows the spread of the fire allowing more time for persons to evacuate. Methods include fire-resistant floors, doors and walls.
The amplitude difference between the most positive and the most negative excursions of a signal.
People Counting
People counting is a useful form of security software that can collect data from counting the number of people accessing a certain area.
Perimeter Detection
A perimeter detection system can alert whether an intruder is on the perimeter of premises before entering the building. It is a good form of early intrusion detection.
Pinhole Lens
A lens with a relatively small front opening so it can be used in covert application.
A passive infrared sensor or otherwise referred to as a PIR motion detector is an electronic sensor that can measure radiating infrared light from objects. They are used commonly in security alarms.
Pixel or otherwise known as a Picture Element is a photo sensor site in an image sensor like a CCD chip. This converts the input light image onto an electronic signal.
Powerline Networks
This is a type of technology whereby the existing cabling system is utilised to provide an Ethernet connection between the CCTV camera and the recorder. This negates the need to run Ethernet cables in addition to the existing power cables. Commonly used for Marine CCTV applications.
Point-to-Point Protocol. This protocol is used for communications between two different computers using a serial interface.
A ‘Point-to-Point Protocol over Ethernet’ or PPPoE is a form of broadband connection which provides authentication such as a username and password. It also provides data transport.
The pre-positioning of pan, tilt and zoom cameras by the use of potentiometers in the moving parts of the camera head. This can control equipment to move to a set reference point when the controller dictates or when an alarm exists.
The Public Switched Telephone Network is the aggregate of the world’s circuit telephone networks. These are operated by local, regional or national operators in order to provide telecommunication infrastructure.
Push to Exit or otherwise referred to as PTE is a self-resetting device in the form of a stainless steel button that can trigger opening a door when it has been pressed and activated. It is then reset after the door closes again.
A Pan-Tilt-Zoom cameras are a useful form of security camera and can have more capabilities such as remote control and direction. They are usually in the form of dome cameras.
Public Address
Public IP addresses are commonly used outside of a network and are provided by an Internet service provider (ISP).


A Quality Management System is a clearly defined set of business policies, processes and standards.
Quad Splitter
Combines up to 4 video inputs into one channel and displays them on one monitor screen split into 4.


Random Access Memory. The RAM or Random Access Memory is a place in a computer operating system where application programs, and current data is kept temporarily so that they can be quickly reached by the computer's processor.
The Radio Corporation of America. RCA is conveniently used to describe phono jack and plug, one of the audio/video connectors.
Camera systems that are redeployable are designed to be set-up and transported from one location to another easily and to view live and record events remotely.
Remedial Works
Remedial work involves fixing or repairing equipment that has become faulty.
Remote Monitoring
Internet connection can take images from a CCTV camera device and send them directly to an external remote monitoring system. These systems can then respond to any activity they deem suspicious to prevent any criminal damage or activity.
RG59/U Cable
One of coaxial cables suitable for video transmission in CCTV systems.
A device on the Internet that determines the next network point to which a data should be forwarded.
RD-232 Port
Transmits luminance and color portions separately, using multiple wires, thus avoiding the color encoding.


Transmits luminance and color portions separately, using multiple wires, thus avoiding the color encoding process and its inevitable loss of picture quality.
This is a color television system used in France, Russia and other countries that do not use either the NTSC or PAL system. It has 625 horizontal scan lines and 25 frames per second.
Sequential Switcher
Video Switcher. A device that allows the video signals from multiple cameras to be displayed on a monitor, or recorded on a VCR one at a time in sequence.
A computer program that provides services to other computer programs in the same or other computers. Or, the computer that a server program runs.
Signal-to-Noise (S/N) Ratio
The ratio between the television signal and the noise; expressed in decibel(dB). The higher the number the better.
Simple Mail Transfer Protocol. TCP/IP is a communication protocol for electronic mail transmissions or emails.
SVHS Super Video Home System
Super VHS is a higher quality extension of the VHS home videotape format.
Either known as a Sequential Switcher or Video Switcher. This is a device that allows the video signals from multiple cameras to be displayed on a monitor, or recorded on a VCR one at a time in sequence.


TCP or otherwise referred as ‘Transmission Control Protocol’ is a set of rules to exchange messages with other Internet points at the information packet level.
Transmission Control Protocol / Internet Protocol. This is the basic communication language or protocol of the Internet.
Thermal Camera
A thermal camera is a unique feature built into a security camera device that can detect infrared (heat) energy, and can then convert this into a visual image.
Time/Date Generator
Installed between a CCTV camera and a monitor. This generates the information of Date, Time and camera ID.
Time Lapse
A video recorder that can be set to record continuously over a long period of time. This can be anything from two hours to 960 hours.
Tracking or auto-tracking is an advanced method of PTZ cameras which enables a single PTZ camera to automatically detect and record moving objects and cover a large space and area.
Turbo(HD over CO-AX cable)
This is a method of transporting HD videos over a traditional analog CO-AX cable. This is an easier method to carry the HD signals without having to upgrade any digital equipment.
A turret is a type of security camera that has a ‘ball-and-socket’ design. Due to it’s design, the camera can be easily swiveled around once the base has been mounted.


VHS or commonly referred to as a ‘Victor Home System’ is used by most VCRs as the recording medium with 240 lines resolution.
Video Analytics
By capturing and reviewing video analytics, you can identify different events, motion detection, vehicle and people counting, queue detection, facial recognition and more. It is a useful process of security analysis and business intelligence.
Video Band
The frequency band used to transmit a composite video signal.
Video Switcher
Switcher or Sequential Switcher. A device that allows the video signals from multiple cameras to be displayed on a monitor, or recorded on a VCR one at a time in sequence.
Videocassette Recorder
A VCR is a device that accepts signals from a video camera/microphone and records video/audio on magnetic tape in a cassette. The VCR can play back recorded video/audio on a television set or CCTV monitor.
Visitor Management
Visitor management is a security process that manages and tracks any usage of a site or building. These systems can record where visitors access, what time of day and the usage of any facilities.


Wall Mounted
Wall mounted CCTV devices and cameras can be mounted to any wall.
WAN or otherwise known as a ‘Wide Area Network’ is a telecommunications network which extends over a large geographical area for computer networking purposes.
Wide Dynamic Range (WDR) cameras contain software that allows the cameras to balance the lighting in a dark and light image, to therefore make it appear clearer.
Web Camera
Or commonly known as a Web Camera Server is a CCTV Camera with built-in web server computer.
Web Server
A computer program that serves requested HTML pages or files.
If you have a wireless security camera, the video and audio signals are transmitted over wireless networks such as the internet, to the end receiver. This will then connect to your viewing device. Devices can also record and save footage to view at a later time.


Zoom Lens
The mechanical assembly of different lens elements so that the focal length can be varied including the angle of view. Zoom lens differs from a fixed focal length.
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