AC adaptor Also called a power supply, plugs in to a standard wall outlet to provide 12 volt DC or 24 volt AC power for cameras and other low voltage devices.

Alarm input An input connection to a DVR that triggers the unit to start recording.

Analog There are two main methods to transmit video; analog or digital. Most cameras used in CCTV applications are analog. CRT monitors switchers, multiplexers and quads also are analog devices.

Aperture (iris) A device in a lens which controls the amount of light to be let into the camera. The size of the aperture is controlled by manually adjusting the iris. By increasing the f stop number (f1.4, f1.8, f2.8, etc.) less light is permitted to pass into the camera. ( see AUTO IRIS)

Audio Most DVRs support audio and can be configured with microphones.

Electronic shutter The ability of the camera to compensate for moderate light changes in indoor applications without the use of auto iris lenses

Auto Iris Auto Iris Lenses adjust for changing light conditions. If the amount of light increases, the lens will electronically reduce the aperture size so the picture remains clear. Required for all outdoor applications.

CCD Stands for "charge-coupled device" and is the image capture device in CCTV cameras. The size of the CCD chip is normally 1/4" or 1/3".

Compression Compression techniques are used in Digital CCTV to reduce the file sizes of recorded video images which conserves hard drive space and allows for efficient remote transmission of images. Typical compression formats used for video include MPEG-4 & H.264.

Covert Cameras Cameras that are concealed within special housings such as smoke detectors or otherwise hidden from view.

Day Night Camera A "Day/Night Camera" has a very sensitive CCD chip that enables images to be captured in very low ambient lighting (regular lighting - not infrared).

Digital Video Recorder [DVR] A digital video recorder is basically a computer that converts the incoming camera (analog) signal to digital, compresses it, and stores it on a hard drive. The DVR replaces the function of a multiplexer) and a security VCR. DVRs offer many features that were previously unavailable with analog only systems.

Dome Camera A type of camera with dome cover. They may have fixed or vari-focal lenses. Some come with infrared lighting and some are designed to be tamper-proof (also referred to as vandal-resistant). Armor dome cameras are designed to resist vandalism by using a hi-impact reinforced polycarbonate dome casing.

Field Of View The view ( width & height) that the lens captures and displays. See lens chart.

Frame Rate (Frames Per Second) (FPS) Digital recorders are often specified by their total frame rate, i.e. the maximum numbers of frames the unit can record in one second over all channels. Real time recording for 1 camera is 30 FPS. Therefore a 16 channel real time DVR would be capable of recording 480 FPS. DVRs are available with lower frame rates.

Infrared (IR) illumination Infrared cameras or dedicated infrared illuminators use special infrared LED's to project IR light, which enables an IR sensitive camera to capture good quality video, in extreme low light conditions.

IP Rating Ingress Protection Scale - 2 numbers indicating the protection level provided by an outside enclosure against water - e.g. IP66 protected against strong jets of water.

Fixed Lens Means that the field of view is not adjustable. It is " fixed" at a specific angle so you can view wide, standard or telephoto images. The focus of the captured image is achieved manually. There are many different lens sizes to choose from. (see vari-focal lens)


LUX Used to specify how sensitive cameras are to light (measured in lumens/sq meter). e.g. a camera with a LUX Level of 0 can see in pitch black. The lower the LUX Level the better the camera will "see" in the dark.

Monitor Security monitors are used to display images from cameras (or captured on your recording device). There are two basic kinds used in CCTV applications. Analog or composite video monitors are used to display images in analog systems. LCD monitors with analog and VGA inputs are now available for use as public viewing or "spot" monitors or as DVR control monitors.

Monochrome The technical term for black & white images.

Motion detection Refers to the feature standard in most digital recorders where video is only recorded when there is a pixel change (i.e: something in the image moves or changes). This feature conserves hard drive space and saves time when searching through recorded data. The sensitivity can be adjusted to eliminate minor changes from being recorded.

Outdoor housing A weatherproof enclosure, equipped with a fan and heater to protect a standard camera usually in an outdoor environment.

Pan-tilt-zoom (PTZ) camera PTZ cameras allow you to adjust their position ('pan' is side-to-side, 'tilt' is up-and-down and zoom is field of view) .They are controlled by a separate control unit or from a DVR. Due to this added functionality, these cameras tend to cost more than non-PTZ cameras

Quad Splitter An analog device used to display 4 cameras simultaneously on a single monitor. Some are available with looping outputs for system flexibility.

Remote Client Software Software that is supplied with the DVR to enable monitoring at an "off premises" location.

Coaxial Cable Cc-axial cable is used to transmit video signals for CCTV systems, A video signal can be transmitted reliably up to750 ft on RG59U Cable and up to1500 ft on RG6U cable, assuming the only connections are at the camera and DVR. Always use 95% copper shielded cable.

Real time Recording In video applications, 30 frames per second (per camera) is real-time recording. DVRs are available that record less than real time and may be suitable for some applications.

Remote surveillance The ability to view cameras from a remote location. Information is transmitted from the DVR by the internet.

Resolution Refers to how much detail can be captured on a camera then displayed on a monitor. Medium resolution cameras typically capture about 380 horizontal lines of resolution. High resolution cameras can capture 500 lines of resolution or more. The higher the resolution, the more detail in a picture.

Siamese cable A cable that combines power and video cables. Use this type of cable when you are using a common power supply. (See POWER SUPPLIES).

Vari- focal lens A camera lens in which the field of view and focus is not fixed, they are manually adjusted at time of installation.

Video input A connector (usually a BNC style) at a PTZ controller, monitor, quad splitter, multiplexer or recording device that you can plug in a video cable.

Weatherproof A device that is weatherproof can be installed outside and stand up to harsh weather conditions and temperatures. However, it does not mean that it is waterproof. (seeI.P.RATING)

Wireless camera Wireless cameras allow the transmission of video to a receiver without having to run video cable. Power is needed at both the camera and receiver locations.

Wide Dynamic Range

Zoom Lens The image can be 'zoomed' in or out while the view of the camera remains in focus. Seldom used in CCTV systems other than in a PTZ camera. Not to be confused with a vari-focal lens.