Glossary

AC Adaptor

A power supply for just about every electronic device on the market. Also called an "AC adapter" or a "charger" if used to recharge a battery, it plugs into the wall and converts AC current to a single DC voltage in most cases.

Alarm Input 

Some DVRs have alarm inputs which can accept input from a sensor device such as a door contact or a motion detection device. These can trigger the DVR to take action by beginning to record when they have been tripped.

Analog

CCTV cameras that transmit video using coaxial cables are considered to be analog.

Angle of View

The angular range that you can focus the camera without distorting the image. Smaller focal lengths will give a wider angle of view.

Aperture

The opening of the lens which controls how much light can enter the camera.

Aspect Ratio

The ratio of the width to the height of an image or screen.

Auto Iris

A lens which allows the opening of the lens to automatically open or close to maintain proper light levels

Automatic Gain Control

The gain of a signal is automatically adjusted with this feature.

Auto White Balance

A feature on cameras that monitors the light and adjusts the camera’s color accordingly.  

A/V

Audio/Video

Back Light Compensation

This feature allows the camera to adjust the exposure of the entire image to properly show the person in the forefront.

Bullet Camera

A type of camera that has a bullet shape.

CCD

Color Capture Device used by cameras to produce images. CCD chips are higher quality and produce a better image than CMOS chips.

CCTV

Closed-Circuit Television

CMOS

Device used by cameras to produce images.

Covert Camera

A camera that is hidden and easily concealed.

Day/Night

A function that helps cameras adapt to low lighting conditions.

DNR (Digital Noise Reduction)

A function that makes images clearer and reduces video file size.

Dome Camera

A type of camera that has a dome shape.

DVR (Digital Video Recorder)

A security system device that records video from security cameras onto a hard drive.

HD-CVI

This stands for High Definition Composite Video Interface. It gives a high definition solution to those with an analog system already in place. No new cables are required when upgrading existing systems to high definition with this.

HD-SDI

HD-SDI delivers high quality live HD video over coax. It gives image quality that is superior to analog CCTV and provides a cost-effective solution that is easy to install and integrate with existing systems.

HD-TVI

This stands for High Definition Transport Video Interface. HD-TVI can provide HD video of up to 1080p resolution. It is different from HD-CVI and HD-SDI, in that HD-TVI can support video transmission at a longer distance.

IR (Infrared) Camera

These cameras have the ability to capture video in low and no light situations. The IR LEDs on the camera give it night vision.

IP Network Camera

These cameras, unlike analog CCTV cameras, can send and receive data via a computer network and the Internet.

IP Waterproof Rating 

An IP rating consists of the letters “IP” followed by a two-digit number. The first number represents the level of protection the camera has against solids, moving parts, and dust. 0 is the least protected to 6 being the most protected. The second number represents the level of protection against moisture, fluids, and water. 0 being non-protected and 8 being completely water-proof.

Lux

Unit of light illuminance used as a measure of low-light recording capacity in security cameras. Cameras with a Lux rating of 0.2 Lux or less are considered low-light cameras.

NVR (Network Video Recorder)

A security system device that receives video streams over a LAN or WAN and records them onto a hard drive.

OSD (On Screen Display)

A control panel on a monitor that allows you to select viewing options and adjust components of the display.

PTZ (Pan-Tilt-Zoom) Camera

These cameras allow users to monitor large areas with a single camera. Pan, tilt, and zoom functions can be controlled remotely so you can follow activity and focus in on specific details.

Pixel 

An area of illumination on a display, from which an image is composed.

POE  (Power Over Ethernet)

A technology for wired local area networks that allows the electrical current necessary for the operation of each device to be carried by the data cables rather than by power cords.

Resolution

The number of pixels on display or in a camerasensor. The higher the resolution, the more pixels.

RG59 Cable

A specific type of coaxial cable used for low-power video and RF signal connections.

RG59 Siamese Cable

A specific type of coaxial cable that allows installers to run both the video and power to security cameras using a single cable.

TVL (Television Lines) 

The maximum number of alternating light and dark vertical lines that can be resolved per picture height. The bigger this number is the better quality of the picture.

Vari-Focal Lens

A camera lens with variable focal length in which focus changes as focal length and magnification changes.

WDR (Wide Dynamic Range)

This function of a camera provides clear images even under circumstances where intensity of illumination and light vary.