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Glossary of Terms for CCTV Equipment
Alternating Current Adapter; when plugged to 240 volts/ 50Hz AC Power (usually 117V AC/60Hz in the United States) it produces 12V DC, 24V AC or others. "UL Listed" and "Regulated" recommended. It is also called Power Transformer.
Alternating Current Power. In the UK, the standard AC Power is single-phase 240V AC/ 50Hz and is provided from power outlets in the house. 24V AC power can be produced from an AC Adapter.
Automatically adjusts the video quality in low light condition.
Like Video Motion Detector, detects changes of motion to produce an alarm.
Allows the auto-iris circuitry to either take bright spots more into consideration (peak), bringing out detail in bright areas, or less into consideration (average) bringing out detail in shadows. Select this mode when an auto-iris lens is used.
A procedure or formula for solving a problem.
Continuously variable numerical values such as voltage, current, etc.(The CCD camera produces analogue video signals.)
The scene angle that a video camera lens can show on the monitor, like Diagonal Angle, Horizontal Angle and Vertical Angle, usually described in degree.
American National Standards Institute. This organisation is responsible for approving U.S. standards in many areas, including computers and communications.
The light gathering area of a lens, controlled by the iris.
Address Resolution Protocol; for mapping an IP address to a physical machine address.
American (National) Standard Code for Information Interchange. A standard character-to-number encoding widely used in the computer industry.
American Society for Industrial Security.
The ratio of the vertical to the horizontal image size; 3:4 is the NTSC standard.
A lens designed with a non spherical shape so that it passes more lights or decreases barrel distortion on wide angle lenses.
A decrease or loss in a signal, usually measured in decibels.
Automatically adjusts the lens focus from surrounding scene and keeps a moving object in focus.
Automatically adjusts the video quality in low light condition.
A diaphragm device in the lens that adjusts to light level changes. The iris diaphragm opens or closes the aperture to control the amount of lights coming through the lens.
Allows the auto-iris circuitry to either take bright spots more into consideration (peak), bringing out detail in bright areas, or less into consideration (average) bringing out detail in shadows.
Automatically select the correct termination depending on whether the video output is connected.
Automatically adjusts a colour camera's colour to maintain white areas.
The capacity of the transmission medium stated in bits per second or as a frequency. Or, the amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second. For analogue devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).
Electronically compensates for high background lighting to give detail which would normally be silhouetted.
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.
A lens system that has two different focal length lenses and images two identical or different scenes onto a single camera sensor. The two captured scenes appear as a split image on the monitor.
A numbering system with only two values: 0 (zero) and 1 (one).
Abbreviated with small "b". Binary Digit. The smallest unit of data in a computer.
The process whereby the beam in a CRT is cut off during the retrace period.
Electronically compensates for high background lighting to give detail that would normally be silhouetted.
Bayonet Neil-Concelman or British Naval Connector. A connector widely used in the CCTV industry, usually for coaxial cable. Easy to install and reliable with little video signal loss.
Bits Per Second is the unit used for measuring line speed, the number of information units transmitted per second.
The manual bias control on a cathode ray tube or other display device that controls the average brightness and the contrast of a picture.
An application program that provides a way to look at and interact with all the information on the World Wide Web. Nets cape and Microsoft Internet Explorer are the two browsers that vast majority uses.
Abbreviated with capital "B". A unit of data that is eight bits long and is used by most computers to represent a character such as a letter, number or symbol
An industry standard for lens mounting. C-Mount is 1-inch diameter with 32 threads per inch. A C-Mount lens needs C-ring when it is mounted at a CS-Mount camera.
Complementary - Metal Oxide Semiconductor. A video image sensor chip that produces much lower quality picture than CCD chip.
Video camera's CCD chips format; 2/3", 1/3", 1/4", etc.
Video image sensor. CCD or C-MOS chip.
Cable Access Television.
Charge Coupled Device. A video image sensor chip.
International Radio Consultative Committee; has made the technical recommendation for the European 625 line standard for video signals.
Closed Circuit Television Manufacturers Association.
Closed Circuit Television. It does not broadcast TV signals but transmits them over a closed circuit through electrically conducting cable or wireless transmitter and receiver.
A part of the CCTV system that captures the video pictures.
A part of the CCTV system that receives the video pictures from a CCTV camera and displays them.
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 centre of a shield and isolated from the shield by an insulator.
The degree of mixture of a colour and white. High saturation means little or no white.
A combined signals in a television transmission. The picture signal, blanking signal, and vertical/horizontal synchronising signals are all combined.
Cathode Ray Tube. The vacuum tube part of a monitor or television.
An industry standard for lens mounting. CS-Mount is 1 inch diameter with 32 threads per inch. A C-Mount lens needs C-ring when it is mounted at a CS-Mount camera.
Installed between a CCTV camera and a monitor, it generates the information of Date, Time and camera ID.
Direct Current Power; can be derived from an AC adapter or from a battery. Among DC voltages of 6, 9, 12, 24, 28, 12VDC is most common in the CCTV industry.
The power or voltage ratio of two signals.
Dual Interface Poll switches usually allow you to change the configuration of a circuit board to suit your application.
Detection of Motion Zone
Dynamic Host Configuration Protocol; lets network administrators manage centrally and automate the assignment of IP addresses in an organisation's network.
Multi-wire cable with DIN connectors at both ends. Usually has 5 or 6 inner wires. Different diameter and configuration from maker to maker.
A general term when the object is not shown exactly as is.
1) Domain Name System. A general purpose distributed, replicated, data query service. Its principal use is the lookup of host IP addresses based on host names. 2) Domain Name Server. A computer that converts host names, such as www.pelikancam.com to its corresponding IP Address, such as 67.100.253.111
Dynamic Random Access Memory. Most common RAM (Random Access Memory) for PC.
Digital Subscriber Line. A technology for bringing higher-bandwidth information to homes and businesses over ordinary copper telephone lines.
Digital Video Recorder; records video pictures digitally.
The length of time a switcher displays one camera before sequencing to the next.
Electronic Industries Association. American standard for B/W camera system.
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.
Compensates for moderate light changes in indoor applications without the use of auto iris lenses.
Electro-Magnetic Interference.
The most widely installed Local Area Network (LAN) technology. Specified in a standard IEEE802.3.10/100 BASE-T, the most commonly installed Ether net system, provides transmission speed up to 100 megabits per second.
A private network. It uses the Internet Protocol to securely share part of a business information with suppliers, vendors or others
Federal Communications Commission; controls also wireless camera system as one of the commercial broadcasting systems.
Fixed Focal Length Lens
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.
The number of fields per second.
FOV. 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.
A set of programs that protects the resources of a private network from outside users.
Focal Length. The distance from the centre 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.
Some models of CCTV cameras have built-in Flange-back Adjusting Ring, which adjusts the back-focal distance or picture focus. A C-Ring (5mm spacer ring) is not required when a C-Mount lens is to be mounted to a camera that has built-in Flange-back Adjusting Ring.
Or flash RAM (Random Access Memory). A type of constantly powered non-volatile memory that can be erased and reprogrammed in units of memory called blocks.
Optical or lens speed. Smaller f-number means faster lens.
FL. The distance from the centre 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.
Field of View. 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.
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.
The number of frames per second. The frame frequency is half the field frequency.
File Transfer Protocol. A way to exchange files between computers on the Internet
Degree of contrast in a video picture between output magnitude and input magnitude.
Gigabyte.
A device that adjusts the frequency of internal sync to an external data.
A shadowy or weak image in the received picture, offset to either the right or to the left of the primary image.
Hyper Text Mark-up Language. A set of codes inserted in a file intended for display on a World Wide Web browser page.
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.
Cycles per second.
Internet Control Message Protocol. A message control and error-reporting protocol.
Electrical characteristic of a system or component, expressed in ohms. CCTV industry has standardised 75-ohm impedance.
Invisible light beyond the 750 nanometers (red end of the visible lights).
Internal sync mode that sets to internal 2:1 interlace.
A private network. It may consist of many LAN and/or WAN.
Internet Protocol. 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.
Integrated Service Digital Network. A set of standard for digital transmission over ordinary telephone copper wire.
Joint Photographic Experts Group. A graphic image file or a image compression algorithm.
Kilobyte
Kilobits per second. A measure of bandwidth.
Local Area Network. A group of computers and associated devices that share a common communications line.
Light Emitting Diode.
The area where a lens is mounted. There are two types; C- or CS-Mount.
Optical speed, expressed by f-number. Smaller f-number means faster lens.
An UNIX-like operating system. Very efficient and fast-performing system.
Line Lock mode
The part of satellite dish that hangs off of the arm and looks like a flashlight. It is what captures the digital signal from the satellite.
Lumens per Square Meter; unit of illumination amount.
Multiple Access Television. The method of distributing TV signals by broadcasting them through the air.
Megabyte
Megabits per second. A measure of bandwidth.
Multi-wire cable with Mini-DIN connectors at both ends. Usually has 4 inner wires.
Black and White signal.
The closest distance a lens will be able to focus upon an object. Wider angle (shorter focal length) lenses generally have a smaller MOD than larger focal length (narrower angle) lenses.
Metal-oxide Semiconductor. One of video image chips like CCD, but it produces lower quality video.
A camera lens equipped with 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.
A series of points or connection points interconnected by communication paths.
Undesired signals that corrupt the original video signals and may reduce the image quality.
National Television System Committee; formulates standards for American colour television system. NTSC system has 525 horizontal scan lines and 30 frames per second.
Network Video Recorder. A software or computer that records video on the hard disk. Like a DVR, it usually records digitally so the user can instantly search by time, date and camera. It collects video from network camera, network video server or DVR over the network.
Lens speed, expressed by f-number. Smaller f-number means faster lens.
Optical centreline that passes through the centre of a lens or mirror, etc.
Phase Alternating Line system. A colour television system used in Europe, Australia, parts of Africa and the Middle East. It has 625 horizontal scan lines and 25 frames per second.
A Camera mounting device that allows movement in both side ways and up or down.
Rotating or scanning a camera side ways to view an area in a horizontal direction.
The amplitude difference between the most positive and the most negative excursions of a signal.
Photo sensor site in an image sensor like CCD chip; converts the input light image to an electronic signal.
A lens with a relatively small front opening so it can be used in covert application.
Picture Element. Photo sensor site in a image sensor like CCD chip; converts the input light image to an electronic signal.
Point-to-Point Protocol. For communications between two computers using a serial interface.
Point-to-Point Protocol over Ether net.
The pre-positioning of pan, tilt and zoom cameras by the use of potentiometers in the moving parts of the camera head. These allow the control equipment to store and move to a set reference point when the controller dictates or when an alarm exists.
A special set of rules (in information technology).
Public Switched Telephone Network.
Combines up to 4 video inputs into one channel and displays them on one monitor screen split into 4.
Random Access Memory. The place in a computer where the operating system, application programs, and data in current use are kept temporarily so that they can be quickly reached by the computer's processor.
Reverse Address Resolution Protocol. For host machines that don't know their IP address.
The Radio Corporation of America; conveniently used to describe phono jack and plug, one of the audio/video connectors.
Expressed by TV lines or pixels, it indicates the quality level of video images.
Radio Frequency.
One of coaxial cables suitable for video transmission in CCTV system.
A device on the Internet that determines the next network point to which a data should be forwarded.
A communication port with 15 pins.
Sequential Couleur A'Memorie, a colour 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.
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.
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 used in sending and receiving e-mail.
Sequential Switcher or 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.
Super VHS; a higher quality extension of the VHS home videotape format.
Transmits luminance and colour portions separately, using multiple wires, thus avoiding the colour encoding process and its inevitable loss of picture quality.
Transmission Control Protocol. A set of rules to exchange messages with other Internet points at the information packet level.
Transmission Control Protocol / Internet Protocol. The basic communication language or protocol of the Internet.
Installed between a CCTV camera and a monitor, it generates the information of Date, Time and camera ID.
A video recorder that can be set to record continuously over long period of time. This can be anything from two hours to 960 hours.
Victor Home System; used by most VCRs as the recording medium.
The frequency band used to transmit a composite video signal.
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.
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.
Wide Area Network.
A mathematical function useful in digital signal processing and image compression. In the Internet communications, wave let has been used to compress images to a greater extent than is generally possible with other methods such as JPEG or MPEG.
A CCTV Camera with built-in web server computer.
The computer program (housed in a computer) that serves requested HTML pages or files.
A lens of continuously variable focal length.
Guide created: 06/05/07 (updated 10/06/08)
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