Here are definitions for common terms you may come across as you explore the topic of school security.

Alarm-Activated Recording – A function that controls video recording when an alarm is received. A common application is for a camera and recorder to be activated if a motion detector senses motion in an area after hours.

Asset Control – Protecting physical assets and equipment from theft or vandalism.

Access Control, Access Management – Controlling who enters buildings or rooms, using devices such as card readers, metal detectors or biometric readers.

Backward Compatible – Equipment that is designed to operate with both previous and future models. With backward compatible products, any equipment you add in the future will operate with your current products.

Biometric Readers – Devices that read fingerprints, iris patterns or other individual physical traits. Biometric readers are often used for controlling entry to a room or building.

Camera Tours – Programs that move a pan/tilt/zoom (PTZ) camera in a predefined pattern. Tours can be used to sweep an area at regular intervals, monitoring a larger area than a fixed camera could.

Card Reader – A device that reads data encoded in the magnetic strip of a smart card.

CO2 Sensor – A safety device that detects carbon monoxide levels in the air and sounds an alarm if they approach dangerous levels.

Coaxial Cable – A type of cable capable of transmitting a range of frequencies with low signal loss. Commonly used for transmitting video and audio in security systems.

Digital Recording – Technology that enables video images to be stored on a hard drive or other digital storage medium rather than on an analog medium such as a videotape.

Digital Video Multiplexer and Recorder (DVMR) – A device combining a multiplexer, which can send and receive signals from multiple cameras, with a digital recorder that captures images from the cameras.

Ethernet – A type of local area network (LAN) used to connect multiple devices into one system. An Ethernet can be used to connect a security system so it can be accessed and controlled from different points within the network.

Fiber Optics – A method of transmitting video, audio and data that uses thin filaments of glass to carry the information in the form of light. Fiber optic transmission sends video with less signal loss than other transmission methods.

Fiber-Optic Loop – An asset control device that uses a loop of fiber-optic cable to secure a piece of equipment. If the cable is cut or otherwise broken, the device transmits an alarm signal.

Intrusion Detection – Using devices such as motion detectors to monitor after-hours activity inside or around buildings.

Joystick Keypad – A controller keypad that includes a joystick for customized remote control of a pan/tilt/zoom (PTZ) camera. The joystick is used to move a camera up, down, left and right.

Local Area Network (LAN) – A network of devices such as cameras, monitors, recorders and computers that are connected so that information can be sent between devices. A common use of a LAN is to connect security equipment so it can be accessed and controlled from different points within the network.

Matrix Switcher – A device that routes any of its inputs to any of its outputs. Inputs are normally cameras or alarms, and outputs are normally recorders or monitors. A matrix switcher allows a user to control what information is sent where within a large security network.

Motion Detector – An electronic device that senses motion within a target area and sends an alarm. Common types of motion detectors include passive infrared (PIR) and range-controlled radar models.

Multiplexer – A device that accepts video signals from more than one camera and encodes them onto one signal that is sent to a digital recorder or VCR. The multiplexer also decodes the recording so it can play back video from one camera or several cameras at once on a monitor.

Panic System – A network of buttons or mobile devices used to send signals to a central location during an emergency. Fixed buttons can be wired or wireless, while mobile devices use wireless technology. The devices can send specific information such as the name of the person and the room location the alarm is coming from.

Pan/Tilt/Zoom (PTZ) Camera – An electronic camera that can be moved left, right, up or down as well as zoomed in to get a magnified view of an object or area. A PTZ camera monitors a larger area than a fixed camera.

Passive Infrared (PIR) Detector – A device that senses body heat to detect motion.

Range-Controlled Radar – A radar detector that detects motion by transmitting signals and measuring the time it takes them to return. Range-controlled means the user can select precise distances to measure, providing more accurate motion detection. Because radar passes through most solid surfaces, this type of detector can be concealed within doors or behind walls.

Recessed Sensor – A sensor for a motion detector or other intrusion detection device that is mounted flush to a surface or just beneath it, to protect the sensor from tampering or destruction.

Smart Card – A small card with a magnetic strip for encoding data. The encoded data is scanned by a card reader, most often for the purpose of access control or to complete transactions.

Twisted-Pair Wire – A cable composed of two small, insulated conductors twisted together. Because both wires have nearly equal exposure to any interference, unwanted noise is substantially reduced. Many buildings have existing twisted-pair wiring that can be used to send video, audio and data signals as part of a school security system.

Video Motion Detection – A function in which a multiplexer or DVMR “looks through” a camera to detect motion within that camera’s view. If motion is sensed, recording is initiated to capture images of the motion.

Wide Area Network (WAN) – A group of Local Area Networks (LANs) connected into a larger network system. In school districts, each campus could have its own LAN and all the LANs could be connected into a WAN using fiber-optic cable or telephone lines.

Wireless Transmission – A technology in which electronic devices send information to receivers using radio waves rather than wiring.