Security Terms & Definitions
A/V -- Audio / Video
AC Adaptor -- See: Power Supply - All CCTV devices require power of some sort. Electricity in the United States comes in one form, 110 to 120 AC. The AC adaptor converts the AC power to DC power and will adjust it to a specified amperage. Power supplies should come included with each item.
AES -- Auto electronic shutter - the ability of the camera to compensate for moderate light changes in indoor applications without the use of auto iris lenses.
Alarm Input -- A connection from an alarm or sensor that triggers the CCTV unit to start recording if activated.
Analog -- Two main methods exist for representing data in electronics -- Analog, and Digital. Analog is pertaining to a mechanism that represents data by measurement of a continous physical variable, as voltage of pressure.
Analog System -- Analog cameras are used most often in CCTV applications. Other examples of of Analog devices are security VCRs, switchers, multiplexors, and quads. CCTV systems that consist of Analog devices are considered Analog Systems.
Angle of View -- Regarding CCTV security cameras, this term refers to the angular range in degrees that you can focus the camera without distorting the image. When focus is distant, the Angle of View is smaller or narrower. When focusing up close, you can generally see a wide Angle of View.
Aperture -- The Aperture is the opening of a lens that controls the amount of light let into the camera. The size of the Aperture is controlled by the iris adjustment. By increasing the stop number less light is permitted to pass into the camera.
Armor Dome Camera -- Armor Dome refers to a hi-impact reinforced polycarbonate dome casing designed to resist vandalism on this brand of camera.
Auto Electronic Shutter -- A CCTV camera feature that allows the camera to compensate for moderate light changes in indoor applications without the use of Auto Iris Lenses.
Auto Iris Control -- A lens which allows the Aperture to automatically open or close to maintain proper light levels on the faceplate of the camera pickup device.
Auto Gain Control -- An electronic circuit used by which the gain of a signal is automatically adjusted as a function of its input or other specified parameter.
Auto White Balance -- A feature on color cameras that constantly monitors the light and adjusts its color to maintain white areas.
AVI -- Audio Video Interleave - An audio-video standard designed by Microsoft.
BBalun -- CCTV baluns are a type of transformer which allow video footage to be transmitted much farther distances by converting unbalanced signals to balanced signals.
Black Level -- The level of brightness at the darkest point of a video recording.
BLC Backlight Compensation -- The ability of a camera to compensate in cases where a subject with a large amount of background light would otherwise be obscured by blooming or silhouetting.
Bullet Camera -- A type of camera with a bullet like shape. Can be used inside or out. Some come with infrared lighting.
C-Mount Camera -- C-Mount or Standard Body cameras are designed to accommodate custom lenses. The lenses can be removed and replaced. Standard Body Cameras are the basic model and offer the most diverse range of features.
CAT5 -- Category 5 (cable) - type of cable most often used in networking applications.
CAT6 -- Category 6 cable, also commonly known as CAT5e, or network cable. Offers increased bandwith through speeds at the cost of less durability when compared to CAT5.
CCD -- Charge-Coupled Device - CCTV security cameras produce images using CMOS or CCD chips. CCD chips are higher quality and produce a better image than CMOS. Also known as a Color-Capture Device.
CCIR -- CCIR dictates the number of analogue security cameras that can be recording at any time, influenced by DVR strength.
CCTV -- Closed-Circuit Television. Refers to the secure connection between an analogue camera and the access point of security camera footage.
CMOS -- Complementary metal-oxide-semiconductor -A major class of integrated circuit technology used for a wide variety of analog circuits such as image sensors, data conveters, and highly integrated transceivers for many types of communication.
Cable -- The wiring used to connect electronic devices. Cables transmit different kinds of signals such as video, power, data, and audio signals. Refer to plug and play cable and RG59 Siamese cable for more information.
Compression -- Compression is the act of taking an incoming signal or image, which can be analog or digital, and restructuring the data such that it takes less resources for storage and transmission.
Concealed Cabling -- Intentionally feeding a camera's video and power cables through a mounted bracket, which protects camera wiring from both the elements and criminals attempting to disable cameras by cutting their wiring, and can also be used simply for aesthetic purposes.
Covert -- A covert application refers to a situation where you don't want the person to know that they are being watched or recorded. Also known as 'hidden' cameras.
Day / Night Camera -- Not to be confused with Infrared Cameras, "Day/Night Cameras" are regular cameras with a highly sensitive CCD chip with the ability to capture quality imagery with very little light present.
Digital -- Two main methods exist for representing data in electronics, Analog and Digital. Digital information is communicated by designating a circuit on or off.
Digital System -- Digital CCTV security camera systems are only lately gaining popularity. Most security cameras are still analog, though DVRs are becoming the industry standard. There are some digital cameras available but they are extremely expensive. Most new systems installed today will include analog security cameras and a DVR. Any CCTV security camera system that includes a DVR is considered a Digital Sytem.
Dome Camera -- A type of camera with a dome-like shape. Most often used indoors. Some feature infrared lightning and some are designed to be tamper-proof, such as the Armor Dome Camera.
DNS -- Dynamic Name Service is simply a database of IP addresses and Domain Names. This database is responsible for telling the internet how to route a request based only on a name and not an IP address. GeoVision supports the use of dynamic IP's for it's DVR servers and through their Dynamic DNS service you can always find your server based only on it's domain name.
Duplex -- A duplex grants the ability to transfer data in and out of the recorder at the same time. In example, a full duplex DVR can continue capturing and recording images even while a different image is being displayed.
DVR -- Digital Video Recorder - A Digital Video Recorder, when applying to an CCTV security camera application, is a computer that coverts the incoming (analog) signal from cameras to digital, and compresses and stores the data. The DVR replaces the function of a multiplexor and a security VCR.
Dwell Time Programming -- Programming that allows a user to control the amount of time a CCTB multiplexer displays one camera before sequencing to the next.
Fail Safe/Secure -- A feature of access control systems, fail safes ensure that locks automatically engage during power outages to guarantee security.
Field Of View -- The visible area of a lens. With security cameras this area will vary depending on the distance from the camera to the subject and the type of lens being used. A field of view calculator is used to determine the field of view with various distances and lens settings.
Focal Length -- Focal Length tells you the strength of the lens. The longer the Focal Length the narrower Angle of View, the shorter the Focal Length the wider the Angle of View.
FPS -- Frames Per Second - in digital video applications, refers to the number of video images that can be captured, displayed, or recorded in a second. Also referred to as the 'frame rate' or 'refresh rate'.
F-Stop -- The speed of a camera lens. The smaller the F-number, the larger the amount of light that passes through the camera's lens.
FTP -- File Transfer Protocol - Network protocol of transfering files from on computer on a network to another computer on the same network.
GHz -- Gigahertz
GUI -- Graphic User Interface - The interface through which users can interract with their security camera features, footage, and recordings.
H.264 -- A motion compensating video compression standard that is one of the most common formats for recording, compression, and video distribution.
HD-SDI -- A short-distance recording solution that offers 720p to 1080p resolution video through analog cameras using standard coaxial cables.
Hertz -- Hertz (Hz) is a measure of the number of variations per second in a video feed.
Housing -- Covering or container featured on some cameras designed to protect from it from the weather.
Infrared -- Infrared radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red", red being the color of visible light with the longest wavelength.
Infrared Camera -- Infrared Security Cameras have special infrared lights installed around the outside of the camera lens. Through use of this special light the camera can capture a good picture even in total darkness.
IP -- Internet Protocol Address is a unique address given to certain computer or electronic devices. An IP address is necessary for devices to identify and communicate with each other. An IP address is required for positive unique identification of any device on a network or the internet.
Iris -- The Iris (on some lenses) controls how much light is let into the camera lens.
JPEG (or JPG) -- Pronounced "jay-peg" and stands for "Joint Photographic Experts Group" who designed the standard. This is a standard way of compressing images which works particularily well for photographic images (as opposed to graphic art).
Junction Box Mounting -- A common mounting used for outdoor security cameras that allows cameras to be mounted directly to an already installed junction box.
LAN -- Local Area Network. A group of computers and other devices in a small, local area networked together to share files.
Lens -- The lens of the camera determines the angle of view (Field of View) and the focus of the captured image. There are many different lens options.
Line Locked -- When a security camera is on the same phase as its AC power supply.
Low Light -- Refers to very dim lighting, even 'normal' darkness. Complete darkness is 0 lux. Infrared cameras work well in very low light conditions.
Luminance -- Intensity of light on any surface per unit of foot-lambers (fl). Lux -- Refers to the amount of light required for a camera to capture a good image. Infrared cameras have very low lux.
MHz -- Megahertz
Micro Camera -- Very small cameras designed to work in covert applications where you don't want people to know that the camera is there. Also called 'hidden cameras'.
Monitor -- Security camera monitors are used to display the images captured by your cameras. They come in analog and digital versions.
Motion Detection -- A feature in some VCRs and DVRs to only begin recording video if something in the image moves or changes. Good for monitoring an area that is not heavily trafficed, and saves a lot of hard drive space.
Mounting Bracket -- Various different kinds of mounting brackets are used to install cameras to the wall or ceiling.
MPEG (or MPG) -- Pronounced "em-peg" and stands for "Motion Picture Experts Group" who designed the standard. This is a standard way of compressing audio and video files. (It's also the technology behind the now world-famous MP3 music files.)
Multiplexer -- A device that can accept a number of camera inputs and almost simultaneously display them on a single monitor and/or record them. Multiplexers can also be used to transmit multiple cameras over the same transmission medium.
Network IP Camera -- A security camera that requires a high speed internet connection and an IP address to transmit recordings directly through a network.
Network Video Recorder -- A Network Video Recorder (NVR) is a storage device that saves surveillance camera footage onto hard disks, allowing computers networked to the NVR to playback footage at any time.
On Screen Display -- A feature of some cameras that allow users to adjust camera settings directly through an interface on the camera itself, instead of requiring users to rely on a camera's factory default settings or forcing the user to change settings through a DVR.
Outdoor Camera -- Outdoor cameras come in special weatherproof housings that allow them to stand up well in tough weather and temperature conditions.
Overwrite Protection -- A feature that allows NVR and DVR operators to prevent existing files from being automatically overwritten if the device's storage space is full.
Pan-Tilt-Zoom (PTZ) Cameras -- PTZ cameras allow you to adjust the position ('pan' is side-to-side, 'tilt' is up-and-down) and focus ('zoom') of the camera using a remote controller. Due to this added functionality, these cameras tend to cost much more than non-PTZ cameras
Pin-Hole Camera -- Pin-hole cameras have a very small lens that can see through a small hole. These types of cameras are used in covert applications. A disadvantage of pin-hole cameras is that they require more lighting than normal cameras to capture a good clear picture.
Plug and Play Cable -- A cable that makes wiring cameras easy. Each camera needs to have a power wire and video wire (and sometimes an audio wire too), plus the connectors at the end of the wire to plug it in. The plug and play cables have all three wires built into one cable with the connectors already attached. The only disadvantage of plug and play cable is that the signal tends to degrade if run distances. For DVRs - plug and play cables can be run reliably up to 100 ft. For analog systems - plug and play cable can be run up to 400 ft. If you need to run longer distances then you need to use the RG59 Siamese cable.
POE Power Over Ethernet -- an adaptor that allows you to transmit power to a security camera through CAT5 (aka ethernet) cable.
Post-record -- This is a DVR's ability to record after a motion detection event has occurred. It records for a specified amount of time after the event has been triggered, even though the motion may have ceased.
Power Supply -- See: AC Adaptor - All CCTV devices require power of some sort. Electricity in the United States comes in one form, 110 to 120 AC. The AC adaptor converts the AC power to DC power and will adjust it to a specified amperage. Power supplies should come included with each item.
Pre-record -- Pre-record is a setting on DVR systems that applies to motion recording. Normally, when a DVR is set to record motion, it takes a second ro begin recording once the motion has been triggered. With pre-record selected, a buffer of the previous 140 frames before motion was triggered is recorded to the drive, allowing the security camera to capture one or two seconds prior.
Quad -- An analog device used to display 4 cameras simultaneously on a single monitor.
RG59 -- An RG-59 is a common co-axial cable used in CCTV applications.
RG59 Siamese Cable -- This type of cable combines the power wire with the video wire. You have to add your own connectors to each end of the cable. Use this type of cable when you need to run distances longer than 100 ft with a digital system, or more than 400 ft. with an analog system.
RCA -- An electrical connector invented by Radio Corporation of America, from which its name is derived. Consists of 3 wires - red, yellow, and white, these are commonly used on a wide assortment of products in the audio/video market.
Real-Time Recording -- In digital video applications, 30 frames per second per camera (see above) looks just like real-time. There is no hesitation or jerkiness in the video.
Remote Surveillance -- The ability to view your cameras from a remote location. Information is transmitted via phone line or internet.
Resolution -- Refers to how much detail can be captured on a camera or displayed on a monitor. Cameras typically capture about 380 horizontal lines of resolution. High resolution cameras may capture 450 lines of resolution or more. The higher the resolution, the more detail that can be captured in a picture. The monitors and recording devices can generally handle at least as much resolution as the cameras can capture.
RS-485 -- A protocol that allows users to change the settings of their cameras without having to physically be where the cameras are.
Smart Search -- This is a feature of our digital video recorders that allows you to search for changes in a particular area of an image over time. For example, if a wallet was stolen off of a table, you could go to a point on the video where the wallet is there, draw a virtual box around that area, then search the video recording for changes to that particular area. This would allow you to locate the exact point on the video where the wallet was removed.
Sun/Rain Shield -- An adjustable shield that allows cameras to see through sun glare or raindrops accumulating on the camera.
. S/N R-atio -- Signal to Noise Ratio; this number represents how much signal noise the camera can tolerate and still provide a good picture. The higher the number the better.
Switch -- A switch will take multiple camera inputs and will show them on the monitor one at a time. Unlike a quad it will not display them all at once, instead it sequences through them showing one camera at a time. It will also allow you to select a particular camera to view.
Tamper Detection -- A notification system that sends an alert to camera operators if the viewing angle of the camera has been tampered with, or if the camera's field of view has been blocked.
Time-Lapse VCR -- A VCR that can be set to slow down its recording rate in order to extend the length of time that can be recorded on a standard tape up to as much as 960 hours. This is possible by recording one frame at time at set time intervals. Most units have an alarm input signal so it can be automatically switched to real time mode in case of an alarm.
Transformer -- A device used to transfer electric energy from one circuit to another, especially a pair of multiply wound, inductively coupled wire coils that effect such a transfer with a change in voltage, current, phase, or other electric characteristic.
Twisted Pair -- Two independent cables twisted together, allowing them to cancel out external signal interference.
Varifocal Lens -- A camera lens in which the focus is not fixed, it can be manually or automatically adjusted.
VCR -- Videocassette recorder; an electronic device for recording and playing back video images and sound on a videocassette.
VHS -- VHS (Video Home System) is a widely-adopted videocassette recording (VCR) technology that was developed by Japan Victor Company (JVC) and put on the market in 1976. It uses magnetic tape 1/2 inch (1.27 cm) in width. Originally, the abbreviation VHS stood for Vertical Helical Scan, and was later changed as the technology gained in popularity.
Video Capture Card / DVR card -- Computer cards that you can install on the motherboard of your own computer to create your own video recording computer. Due to compatibility issues with this type of device, we do not sell these separately.
Video Gain -- An increase in video signal power by an amplifier, expressed as the ratio of output to input. Also called amplification.
Video Input -- A connection in a video controller or recording device that you can plug a camera into. The more video inputs (also called camera inputs) available on a device the more cameras you can connect to it.
Watch Dog Timer Circuit Protection -- If problems are detected in the DVR computer the system will automatically reboot to correct the problem.
Waterproof -- A device that can be immersed in water and still function properly.
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.
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).