CCTV Glossary


Advanced Alarm Control: A flexible alarm management subsystem that allows rules to be created that define which input(s) activate one or more outputs.


Analog High Definition: Is a resolution that transmits HD digital video in a surveillance system. With AHD, high definition digital video can be transmitted without difficulty over coaxial cables or basically over the air.


The aperture is the width of the lens that regulates the volume of light that grasps the image sensor.

Alarm Input

An input connection that generates to a security VCR or DVR to start recording if the alarm is triggered.


Audio/Video Interleave: An AVI file is a sound and motion picture file that conforms to the Microsoft Windows Resource Interchange File Format (RIFF) specification


A technique of boosting the video signal level to produce a full amplitude video signal, even when the scene contrast is less than full range (glare, fog, mist, etc.). The darkest part of the signal is set to black and the lightest part to white.


Fully integrated, high speed, pan/tilt/zoom camera built into a protective dome housing allowing full and continuous 360° coverage of the scene.


The lens continuously adjusts to the correct focus automatically for the sharpest picture.


The camera pans continuously between right and left limit settings.


This function records the sequence of movements of the camera’s PTZ for later playback allowing a set pattern to be repeated automatically.


Auto White Balance: A feature that allows a color camera to automatically adjust its output color to give a natural color, independent of the lighting used.


A lens with an electronically controlled iris. This allows the lens to maintain one light level throughout varying light conditions.


Back Light Compensation: A feature on newer CCD cameras which electronically compensates for high background lighting to give detail.


A communications protocol that allows remote control, configuration, and updates to be performed over the video cable.

BNC connector

Is a type of connector used to interconnect two coaxial cables or connect a cable with other CCTV components.


The baud rate is how many bits can be sent or received per second.

Bullet Camera

This is a bullet like shaped camera that can be used indoors or outdoors. Some come with infrared lighting.


Bit/s Bits per second, the actual data rate.


Charged Coupled Device: A type of solid state image sensor used in CCTV cameras.


Closed Circuit Television: A video system that transmits television signals over a closed system.


Common Intermediate Format: Video format with 352 × 288/240 pixels.


Configuration Tool for Imaging Devices: Bosch software used to configure and update cameras and other remote devices over video cable using Bilinx, and to save them for later use.


Composite Video Blanking and Sync: The format of an analog television (picture only) signal before it is combined with a sound signal and modulated onto an RF carrier.

Category (CAT) 5 Cable

Cable that is capable of transmitting data at high speeds (100 megabits per second and faster). CAT 5 cable is commonly used for voice and data applications. Usually comes with RJ45 connectors.


Complementary Metal Oxide Semiconductor. Similar to a CCD, it also detects light for conversion into a signal. Lesser image clarity than CCD, but more compact in size with lower power usage.


Short for compressor/decompressor, a codec is any technology for compressing and decompressing data. Codecs can be implemented in software, hardware, or a combination of both. Examples of Codecs include Wavelet, MPEG4, JPEG.

Composite Video Signal

The combined picture signal, including vertical and horizontal blanking and synchronizing signals.


The range of light to dark values in a picture or the ratio between the maximum and minimum brightness values.

Day/Night Cameras

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).


Digital Video Recorder :it  is basically a computer that converts the incoming (analogue) signal from the cameras to digital, and compresses it, and stores it. The DVR replaces the function of a multiplexer (or quad or switcher) and a security VCR.


The deviation of the received signal waveform from that of the original transmitted waveform.

Distribution Amplifier

A device that provides several isolated outputs from one looping or bridging input, and has a sufficiently high input impedance and input to output isolation to prevent loading of the input source.


A circuit that permits transmission in both directions. In CCTV, duplex is often used to describe the type of multiplexer that can perform two functions simultaneously: recording in multiplex mode and playback in multiplex mode.

Dynamic IP address

The term used to describe how an IP address is dynamically assigned to computers as and when needed. Unlike Static IP addresses, the IP address is temporary e.g. when you connect to your ISP using a dialup connection , you PC or router will be dynamically assigned an IP address whilst you are online.


Dynamic Noise Reduction: A digital video processing technique that measures the noise (image artifacts) in the picture and automatically reduces it.


Domain Name System: A service that stores domain names and translates them into Internet Protocol (IP) addresses.


A high-performance, smart surveillance camera series designed by Bosch utilizing 10 and 15-bit digital video processing.


One of the two equal but vertically separated parts into which a television frame is divided in an interlaced system of scanning. A period of 1/60 second separates each field start time.

Field of View

The maximum angle of view that can be seen through a lens or optical instrument.

Focal Length

Of a lens, the distance from the focal point to the principal point of the lens.

Focal Plane

A plane (through the focal point) at right angles to the principal point of the lens.

Focal Point

The point at which a lens or mirror will focus parallel incident radiation.


The total area, occupied by the television picture, which is scanned while the picture signal is not blanked.


Frames per Second: This refers to the number of pictures that can be recorded or displayed per second. A television displays 25fps and is referred to as real time.

Focal Length

The distance from the optical center of the lens to the image of an object located at an infinite distance from the lens. Long focal lengths give a small field of view, while short focal lengths give a wide angle view.


File Transfer Protocol: Used to transfer files between computers on a network, such as the Internet.


A single video image.

Frame Rate

The quality of a Digital Surveillance Systems is often determined by the Total Frame Rate it can record at. The higher the Frame Rate, the higher the quality of recording and the more Real Time your CCTV recording will be – Real Time recording for 1 camera is 30 Frames Per Second (NTSC).

Gateway Address

A node on a network that serves as an entrance to another network.


An increase in voltage or power, usually expressed in dB.

Gigabyte (GB)

This unit is typically used to measure large data storage or data transfer capacities (by current standards). 1GB = 1024 MB = 1,048,576 KB = 1,073,741,824 bytes.


This is also known as MPEG-4 AVC.H.264 presents superior video quality, compression adaptability, and tolerance to packet and data loss than that of H.263. It also makes use of bandwidth, producing in the capacity to run more channels over the current systems.


(High Definition Serial Digital Interface) -This type of security camera has the capacity to have megapixel in a standalone DVR. HD-SDI also provides you the capacity to upgrade your system without rerunning coax cables. HD-SDI uses 575 k byte and half the upload broadband speed.


(High-Definition Multimedia Interface) – A digital interface for audio and video that provides a single-cable solution for a set-top box, DVD player, or A/V receiver and an audio and/or video monitor, such as a digital television (DTV).

Housing for CCTV camera

A specific covering or container to secure a camera from intense temperatures or weather conditions.

Hard Disk Drive (HDD)

The storage device usually fixed inside of your computer or DVR used to store information.

IP(Ingress Protection)rating

As specified in international standard IEC 60529, it identifies the degrees of protection provided against the intrusion of solid objects or foreign bodies (including body parts like hands and fingers), dust, accidental contact, and moisture.

Image Sensor or Imaging Sensor

Is a sensor that distinguishes and sends the information that creates an image. It does so by modifying the fluctuating attenuation of waves (as they go through or reflect off objects) into signals, the small surges of current that transmit the information.

IMD (Intelligent Motion Detection)

Is a user-defined graphic motion sensitivity component that reduces false alarms through higher detection efficiency.


Identification: A machine-readable character string.

Infrared Illumination

Electromagnetic radiation (light) with a longer wavelength than is visible to the human eye. IR illumination is prominent at dusk and dawn and in incandescent lamps. IR illuminators come in the form of lamps with the appropriate filters, LEDs, or lasers.

Infrared Camera

Is a non-contact device that identifies infrared energy (heat) and alters it into an electronic signal, which is then sort out to produce a thermal image on a video monitor and make temperature calculations.


Images per Second: a measurement of the rate that pictures are displayed to create a video stream. A rate of 25 IPS (PAL) or 30 IPS (NTSC) is generally considered to be full motion video.


Integrated Services Digital Network: Comprised of digital telephony and data-transport services offered by regional telephone carriers. ISDN


Joint Photographic Experts Group: The name of the committee that created a standard for encoding still images.


The iris (on some lenses) controls the amount of light is passing through the camera lens.


Is an optical device that concentrates or radiates the focus of a light beam through the bending light entering the eye to form an image on the retina.


Light Emitting Diodes  A semiconductor of light that emits infrared or visible light when an electric current passes through it. In CCTV, it decreases the energy consumption and gives a high-caliber quality illumination


Local Area Network: A communications network serving users within a limited geographical area, such as a building or a university campus.


International System (Sl) unit of illumination in which the meter is the unit of length. One lux equals one lumen per square meter.


Media Access Control: A quasi-unique identifier attached to most network adapters (NICs). It is a number that acts like a name for a particular network adapter.


A further development of MPEG-2 designed for transmitting audiovisual data at very low transfer rates.

Night Vision

Cameras that have night vision have the ability to see in low light conditions. To judge how dark it can be for your camera to work, look at the Lux rating on the camera. The lower the lux, the better it will see at night.


The signal level at the output of an amplifier or other device.


The UK’s colour television standard. Abbreviation of “Phase Alternative Line”

Pan and Tilt

A device upon which a camera can be mounted that allows movement in both the azimuth (pan) and in the vertical plane (tilt).


The smallest addressable unit on a display screen or bitmapped image..

Quad Processor

Is a device which uses digital video to display pictures from 4 cameras on a single monitor


A standard network connector, often found at the end of CAT5 cable.


The measure of the fine detail that can be seen in an image. For analog systems this is typically measured in Television Lines or TVL. The higher the TVL rating, the higher the resolution.


Is a type of coaxial cable used for transmission of video signals up to 230m. It is the most popular cable used in CCTV.


Standard European 20 pin connector used for carrying both video and audio signals in domestic TV appliances, now utilised on some CCTV equipment.


Ability to control the integration (of light) time to the sensor to less than 1/60 second; e.g. stop motion of moving traffic.

Time Lapse VCR

A video recorder, most often in the VHS format, that can slow down the recording process and create a time lapse between recorded frames.


Universal Serial Bus  A standard port that enables you to easily connect external devices (such as digital cameras, scanners, and mice) to a PC.


Uniform Resource Locator: Previously Universal Resource Locator. The unique address for a file that is accessible on the Internet.


Video Motion Detection: An algorithm for motion detection in which the camera compares the current image with a reference image and counts the number of pixels (see Pixel) that have changed between the two images.


Is a type of manual zoom lens with a small zoom ratio (ranging between 4mm to 12mm depending on brand).

VCR Activator

A unit, when used with a PIR camera, will automatically instruct your domestic video to record.

Vertical Resolution (TVL)

The number of horizontal lines that can be seen in the reproduced image of a television pattern.

Video Amplifier

A wideband amplifier used for passing picture signals.

Video Capture Card

Computer cards that you can install on the motherboard of your own computer to create your own video recording computer.


Video Graphics Array :The display standard for PC monitors. VGA outputs are compatible with PC monitors.


Video Motion Detection :A method for detecting motion in a video image by checking to see if the pixels in the video image have changed.

Video Server

A video server compresses video signal from analogue cameras to allow them to be viewed over a network such as a LAN or the internet.

Web Server

A DVR or Software system with a built-in web server allows you to view cameras over an internet browser.

Wireless Camera

Wireless cameras allow the transmission of video and audio data to be transmitted to the receiver without having to run wires (using radio waves).

Wired camera

A camera that transmits its signal via cable back to the recording/control device.


Wide Area Network: A long distance link used to extend or connect remotely-located local area networks.


Changing the effective focal length to allow different fields of view to fill the picture area.

Zoom Lens

An optical system of continuously variable focal length, the focal plane remaining in a fixed position.