Glossary of terms used on this site

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Term Definition
Alarm/Event Operation

is a feature found in many CCTV video recording devices like VCRs and DVRs. This allows the user to interface alarm sensors (like a PIR motion detector) with the recording device through an alarm in/out port (this port has a physical electrical contact). An alarm/event capable recorder can then be set to automatically start and stop recording when the alarm is triggered (such as by motion). However, the digital revolution is replacing the need for bulky and expensive alarm sensors. Many newer digital DVR recorders feature advanced video motion detection, which can provide dynamic motion detection recording with built-in software alone.


typically refers to a device which adds strength to a signal for a 'better' and/or longer performance ability. Amplifiers can be found for both wired and wireless equipment. A VDA (video distribution amplifier) is designed to extend a video signal through wires by boosting the power of the video signal. Transmitter-end and receiver-end amplifiers can be found for wireless equipment to help increase broadcast range potential.


of a lens on a video camera controls the amount of light which is allowed to reach the image sensor. Aperture is listed in terms of an F-stop number. As the F-stop number increases (i.e. F/1.4, F/1.8, F/2.8), the amount of light permitted to reach the image sensor decreases.

Auto Iris (AI)

is an electronic circuit that acts as an iris on CCD cameras by electronically shuttering the CCD sensor. Or An automatic method of varying the size of a lens opening in response to changes in scene illumination.

Balance Light Control (BLC)

is a method to compensate for bright spots in the picture. It is also important to consider whether there are bright spots in the picture such as car headlights which can make identification of the vehicle registration or model impossible. This can also be a major problem where it is necessary to identify a person who is moving from bright daylight into artficial daylight. This could result in the subject becoming an unidentifiable silhouette.


indicates the complete range of frequencies over which a circuit or electronic system can function with minimal signal loss. In effect, bandwidth indicates the amount of information and its complexity which can be carried over a signal. More complex information requires more bandwidth for an effective signal. (i.e. color video bandwidth is greater than monochrome video bandwidth, which is greater than the bandwidth for one channel of audio).

Black & White (monochrome) Camera

Cameras are available with either color or monochrome image sensors. Monochrome cameras are typically referred to as black and white because video image they produce is in shades of gray. Only black and white CCD cameras have the ability to utilize IR infrared lighting. Also, even without infrared lighting, a monochrome camera will generally perform better in low light conditions than will a color camera equipped with a comparable CCD imager, lens, and quality of manufacture.


is the type of connector plug commonly found on CCTV devices for video and audio input/output connections. BNC is the choice for broadcast video and security video professionals because of its locking design. BNC plugs are easily adapted to standard consumer RCA connectors using a simple one-piece plug adapter.

Bullet Camera

A bullet design refers to a camera with a cylindrical shape using an inline video imaging chip (rather than a board design). These cameras are sometimes also called "lipstick cameras" or "inline CCD cameras."


stands for charged coupled device. This is a solid-state semiconductor element which uses hundreds of thousands of tiny pixel elements to accept light and translate that information into a vivid, visible picture image. A CCD is one type of camera image sensor. CCDs produce MUCH higher resolution, lower light sensitivity, and better overall video quality than CMOS imagers (also commonly found in CCTV industry cameras).


is the standard monochrome video format used in most of Europe, Israel, and some other places in the world. CCIR products are also generally referred to as PAL because all PAL products can also handle black and white CCIR video. Camera models using the PAL/CCIR video format are common in special applications for users outside the US.


stands for closed circuit television: a video system which will only be monitored in a closed environment (as opposed to public broadcast). The realm of video security and surveillance is also referred to as CCTV.


stands for charged metal oxide semiconductor. This is one type of camera image sensor which uses a charged metal surface to detect light and create a video image. CMOS technology is often smaller than CCD chips are currently capable of, so these cameras can often be quite miniature. Even the highest resolution CMOS cameras cannot compete with newer CCD imagers in resolution, sharpness, and low light performance.

Coaxial Cable

is the most common type of cable used for transmitting a video signal through copper wire. This type of wiring has a coaxial cross-section where an outer shielding protects the actual interior signal conductor from electromagnetic interference. In the CCTV industry, the term "coax" usually refers to RG-59 cable with BNC-type plug ends.


refers to an internal computer component which processes analog information (like a video or audio signal) into a digital format such as MJPEG, MPEG-4, etc. for electronic storage on digital recording media. Without a codec in place to compress and digitize video, digital video recording to a hard disk drive would not be possible.

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