Glossary of terms
|Analogue:||In reference to CCTV, this refers to systems and components that use the standard NTSC/PAL composite video formats. Digital refers to devices that use pixel formats. The definitions become blurred when you conisder that DVRs convert the analog signal into digital form to process the images internally, they convert back to analog to ouput to other devices. Details aside, many people refer to analog as old technology and digital as the new technology.||PTZ Pan-Tilt-Zoom||
System for changing the position of a camera horizontally and vertically and of changing the field of view of the lens in order to observe a different scene. Requires special equipment at the camera and a method of controlling from the viewing area.
|Biometrics:||In CCTV biometrics refers to the hardware/software used to recognise body parts as a method of individual identification. Biometric readers can scan and identify finger prints, Iris and Retinas. Facial recognition is another biometric recognition that comes under the category of video analytics.||Resolution:||
Measure of the ability of a CCTV system, or one of it’s components, to produce detail.Medium Resolution is the description usually applied to cameras with 380 lines, mono or colour. High Resolution describes cameras with 560 lines mono or 460 lines colour.
|CCTV:||An acronym for Closed Circuit Television. Originally this was described as a system with cables directly from cameras to viewing devices with no outside world connections. The Internet has changed all that. Now you can access any DVR with browser software through the Internet.||Roll||
Result of the loss of vertical sync, which causes the picture on a monitor to move up or down.
|Central Station Monitoring:||Monitoring a large number of remote DVRs from a central location using remote software.||Saturation (color)||
The vividness of a color, which is directly related to the amplitude of the chrominance signal.
|Client Server Network:||This is a network where a server (an unattended PC) stores information and shares it with the clients (the attended workstations). The clients depend on the servers for normal operation. The workstations do not necessarily talk to each other.||Scanning||
Horizontal (panning) camera motion.
|Client:||In CCTV DVR context the Client is the PC running the remote software that accesses the DVR or other device. The device originating the video is the Server.||Sensitivity (pickup device)||
The amount of light needed for the pickup device to operate.
|Covert Camera:||A covert camera is not visible to the operator of the system. It is intentionally obscured from view and often used for surveillance of employees. An authorized operator with the proper password privileges can view the camera and recorded information.||Signal to Noise Ratio:||
Ratio between a useful signal and unwanted noise.
|Digital:||In CCTV, digital refers to devices that operate in pixel formats. Analog video devices use traditional NTSC and PAL formats. The lines of difference are blurred when you consider the analog signal is converted to digital and back again (often several times) within a traditional CCTV system. Pure end-to-end digital video is achieved using IP cameras through a network to NVRs and LCD monitors.||Spot Filter:||A small device used to increase the f-stop range of a lens.|
|Dual Stream:||This term is typically used to indicate a device capable of providing two different video compression methods. An example is a DVR that shows live video in M-JPEG and transmits to the remote software using MPEG-4. IP cameras often have selectable (dual stream) transmit capability. This may sometimes refers to two streams of the same compression method with different parameter settings.||Vari-focal Lens:||
Lens with an adjustable focal length, such as 3.5-8mm, 2.6-6mm, and 4.5-10mm.
|DVR:||An acronym for Digital Video Recorder. All recording is on a computer hard drive and can be networked||Vertical Interval:||
The time of the vertical retrace.
|Frame:||One complete TV picture.||Vertical Retrace:||
Return of the electron beam to the top of a TV picture tube or a camera pickup device target at the completion of the field scan.
|Lux:||Unit of measurement of the intensity of light. 10 lux = 1 FC.||Zoom Lens:||A lens that is used as a wide angle, standard, or telephoto lens by varying the lens focal length.|
Normally used in larger camera systems, this switcher allows any of the systems cameras to be routed to any of the systems monitors.
Access Control systems
A means of preventing the sharing of an access control credential. Anti-passback can be based upon disabling a credential for a period of time after it is used, or by remembering the credential-holder’s in/out status.
|Electric Strike:||A door unlocking device that is installed in the door jamb and that works in conjunction with a mechanical lock or latch mechanism.|
The measurement of a physical trait that is unique, such as a fingerprint, hand geometry or iris pattern. In access control this is used to identify authorized users and to grant or deny access.
|Electrified Lock:||A mechanical locking device that has been modified to allow an electric circuit to lock or unlock it.|
|CAT 5:||A very common cable type that consists of several twisted pairs in an overall protective jacket. Used for network cabling and many access control data functions.||Electromagnetic Lock:(Magnetic Lock, Mag Lock)||
A device that locks/unlocks an opening without moving parts, using pure electro-magnetic attraction
(1) An electrical circuit in which current normally flows until interrupted by opening of a switch-type electronic component. (2) A circuit or switch in which the contacts are open during normal operations.
|Fail-safe:||An electric lock that automatically unlocks with any power interruptions.|
|Circuit, open:||(1) An electrical circuit in which current does not flow until permitted by the opening of a switch or a switch-type electronic component. (2) A circuit or switch in which the contacts are closed during normal operations.||Fail-secure:||An electric lock that requires power to unlock. (Most fail secure devices are always unlocked for egress, however.)|
|Contacts:||Electrically conductive points, or sell points, used to make or break an electrical circuit mechanically.||Proximity:||A common access card technology, proximity uses radio frequency to communicate between a card or tag and a reader without physical contact.|
|Controller, Control Panel:||A circuit board or group of circuit boards that contain programming for the operation of an access control or other system.||Reader||A device that obtains data from an access credential (card, tag, etc.) and send the data to a controller for an access decision. (Some units combine reader and controller in one device.)|
Intruder Alarm systems
|Alarm Receiving Centre (ARC):||A secure monitoring station receiving and acting on alarm signals sent from remotely monitored alarm. Signals are monitored 24hours a day and on receipt of alarms the ARC will call police, keyholders and system installers to attend.||Passive infra red movement detectors:||Intelligent devices that provide very stable detection, recognising the difference, for example, between humans and rodents. Electronic chips process the information even further to filter out false alarms.|
|Bell Box:||A self contained high output two tone sounder incorporating a strobe light for visual indication. All electronic components are contained within a secure fully tamper proof enclosure.||Personal Attack Alarm:||A method of manually activating the alarm by a person witnessing a crime or in danger. This alarm activation is treated by police as the highest priority, providing rapid response.|
|Control Panel:||The central part of the system, which controls the system and activates alarms.||Redcare:||Redcare is a widely-deployed standard used in the UK to allow alarm systems to be continuously monitored from an ARC.|
|Detector:||A device used to signal to the control panel if there is any movement in its range. Most detectors are now Dual Technology, combining Passive Infra-Red with Microwave or Ultrasound, providing greater stability and as a result fewer false alarms.||Remote keypad:||A keypad located remotely from the control panel used to set/unset/programme the alarm.|
|Dual-Tech:||Where a single device operates on two different types of technology, eg. where a PIR and a Microwave detector is combined into one movement detector.||Security Grades:||A system under which alarm components are graded (1 to 4) according to the level of protection they afford.|
|Duress Code:||A number chosen by the user that, if used to unset the alarm will act as normal but will also send a personal attack (code 2) signal to the ARC.||Silent Alarm:||Triggered alarm that in mute without audible sounds, the alarm system still transmit the alarm signal to Central Monitoring Station.|
|Keyfob:||The wireless device that can arm and disarm the alarm system, also with panic button for emergency alarm||Silent Part Set:||This feature is available on most control panels. If the engineer has programmed this, when someone part-sets the panel, it will not emit any entry/exit tones. This is particularly useful if there are children in bed and there is a risk that setting the alarm system will wake them up.|
|Keypad:||A input device that allows the user to set, unset and perform additional functions on the system.||Vibration Detectors:||Normally fitted to door or window frames and designed to detect high and low frequency vibration within a range. They can be adjusted to suit local conditions.|
|Motion Detectors:||The devices that detect the movement, there are three major motion detectors: Active Infrared Detector (AIR), Passive Infrared Detector (PIR), Mircowave Motion Detector||Wireless:||A connection between alarm devices that does not use wires. Most wireless connections between system devices use RF wireless signals while wireless connections between security systems and central monitoring stations use cellular signals.|
|Non-Volatile Memory (NVM):||This is a memory chip in the Control Panel which remembers the programmed alarm settings when all power is removed. The NVM can usually be reset to Factory Default settings.||Zones:||An alarm system with many input devices is often separated into a number of zones. Each zone has an indicator light on the keypad which present status of the zone. When all zones are secured alarm system is ready to be armed. In case of alarm, the control panel reports to the monitoring station condition of each zone tripped .|