Security Vocabulary Glossary

Below we have defined some security vocabulary that is used through out our website. The security industry is filled with jargon that describe new technological advancements and services. We will do our best to update the security vocabulary glossary with new terms because security is always evolving.

Access Card

A card, generally the size and shape of a credit card, containing encoded data. The data can be encoded in a variety of ways, sometimes including more than one encoding technology. (i.e. Magnetic Stripe, Proximity, Smart Card, Wiegand.)

Access Control

The physical process of controlling who can access an area and when determined by what they have (an access card), what they know (a PIN), and/or something they are (biometrics).

ACU (Access Control Unit)

An electronic control panel to which readers and alarm devices are wired. The ACU can be a standalone unit or wired to a CPU.


The process or software control that prevents a user from allowing someone else to utilize his or her access card to enter a specific access controlled point while the user is in the protected area. Typically this control is used in parking garages and high-security areas.

AHC (Architectural Hardware Consultant)

A certified consultant with expertise in the design of doors and door locking hardware. AHC’s are typically employed by an architect to prepare hardware specifications


A family of products that electronically scans or reads unique traits of the human body for verification or identification purposes. Biometrics can utilize unique patterns of the iris, retina, hand geometry, or fingerprint.

Biometric Reader

A device that stores enrolled templates of a unique human trait such as a fingerprint, hand geometry, voice, or retina pattern and looks for a match against a live presentation, to grant access to a secure area. Used as an alternate to card readers.

Cylinder Lock

A lock in which a cylinder rotates to move a bolt by inserting the key lifts and aligns the pins to free the cylinder to rotate.

Digital Signal Processing (DSP)

Digital signal processing (DSP) refers to various techniques for improving the accuracy and reliability of digital communications. DSP works by clarifying, or standardizing, the levels or states of a digital signal.

Digital Video Recorder (DVR)

Digital Video Recorder is the industry standard term applied to standalone and PC- based systems that record video images to a computer hard drive providing high quality recording. DVR’s provide a quicker method of retrieving the recorded information unlike media such as VHS tapes and other equipment that stores information.


The act of disabling or shunting a security system or portions of the system to ignore input signals that normally result in alarms. Disarming can occur with user intervention, such as pass codes entered into a keypad, or on schedule through a PC based Access Control System.

Door Control Relay

The relay used to control the unlocking and locking functions of door hardware in an access control system.

Door Forced (Door forced open)

A door forced alarm is the resulting logical alarm that occurs at a portal when the door is sensed to be in an open state without an associated valid access card transaction or an associated REX signal.

Door Held (Door open to long)

A door held alarm is the resulting logical alarm that occurs at a portal when the door was opened after a valid access transaction or a valid.

Door Held Time

The length of time that a portal can remain open after a valid access transaction or valid REX signal before a door held alarm is generated. (Also Door Open Time.)

Door Switch Monitor (DSM)

A device, typically a magnetic based contact, installed in a door to detect the position of the door. The signal from a DSM is connected to a security system to report conditions such as “FORCED” and “HELD” and in instances where electrified locking hardware is included, relocking of the door.

Dual Technology

Utilization of two different technologies in one device to increase reliability and functionality. Dual technology motion sensors, for example, use both passive infrared and microwave technology in order to reduce false alarms and increase detection.

Duress Alarm

A device, such as a push button or pull station, connected to a security system to signal an alarm when an individual is threatened or forced to do something. Bank Clerks typically have a duress alarm installed beneath their counter to signal robbery attempts.

Exit Device

Locking hardware designed to allow immediate exiting at all times, and does not require lever or knob rotation. Usually located on the perimeter doors of a building and always in the designated means of egress route. Sometimes referred to as panic hardware, the touch pad feature of the device allows doors to unlock and open by simply leaning on it.


A lock that defaults to the “unlocked” position when power is removed. Requires power to go to a “locked” position.


A lock that defaults to the “locked” position when power is removed. Requires power to go to an “unlocked” position.

Host Panel

In a security system, an access control unit (ACU) that primarily provides services such as decision making, data base access, or special programs; the primary or controlling panel in a multiple ACU installation.


A pair or group of separate doors equipped with a control system that prevent the simultaneous opening of more than one door at a time. Clean rooms typically include an entry vestibule with a two door interlock that prevents opening the clean room door until the entry to vestibule door is fully closed and vice versa.

Isolation Relay

A relay used to isolate two different systems that must integrate with one another through contact closures, or when the controlling systems relays are underrated for the load.


A device that provides a localized user interface to control a security system or subsystem. Typically includes a numerical 10-key touch pad to allow entering of pass codes and commands.In a security system, an access control unit (ACU) that primarily provides services such as decision making, data base access, or special programs; the primary or controlling panel in a multiple ACU installation.

Local Audible Alarm (LAL)

A device used to annunciate locally an alarm condition or security violation. Locking Hardware Locking hardware is considered to be the electrified lock that controls a portal. Typical hardware includes electrified lock sets, either mortise or cylindrical, electric strikes, electrified panic hardware, and magnetic locks, either face-on or shear.

Mag Lock

Fail safe devices that require constant power to remain locked. They are comprised of a lock body, typically mounted to the door head jamb, and an armature plate which is mounted on the door stile. The armature plate is a passive piece of steel that pivots on its mount, and when aligned with the lock body in its powered state, is magnetically drawn together. Some mag locks are capable of providing up to 2000 lbs of holding force.

Magnetic Stripe

The black or brown stripe that you see on your credit card, airline ticket or access card. The stripe is made up of tiny magnetic particles in a resin. The magnetic property of the stripe allows it to be encoded with a number of bits. In access control this data would include a facility code and card number.

Man Trap

A method used to provide strict access control by preventing access at one specified entrance while another entrance is being utilized. Typically two doors, separated by an enclosed spaced, are interlocked. When one door is opened the second door is incapable of being opened.

Matrix Switch

A video switcher that provides a scalable number of video inputs and monitor outputs, allowing routing of any available input signal to any output signal (cross-point switching). Matrix switchers are usually located at a security operations center where all video concentrates and will display on multiple monitors. Users control the matrix via a joystick keyboard that allows switching and pan tilt zoom control of domes.

Mortise Locks

A lock that requires a pocket, to be cut into the door or piece of furniture into which the lock is to be fitted.

Optical Turnstile

An access control portal that utilizes optical beams (infrared sensors) to prevent tailgating and to grant or deny access into a facility. Units can control single or bi-directional pedestrian access.

Passive Infrared (PIR)

Typically, a sensor device that can sense movement within a specific area and change the state of a set of internal contacts as a result. These contacts can then be wired to a Request to Exit point of an Access Control System for automated egress shunting when a person approaches an Access Point from inside a protected area. PIRs are also common burglar alarm sensors.


A controlled break in a barrier between a more public and a more private space. The control could consist of a card reader on a locked access controlled door.

Programmable Logic Controller (PLC)

A Programmable Logic Controller is a rugged, special purpose computer that reads input signals, runs control logic, and then writes output signals according to its programming.


In access control terms, proximity refers to presenting an access card within the reader’s Radio Frequency (RF) field without having to make actual physical contact with the reader itself.

Proximity Reader

A reader that employs a radio frequency link between the reader and the card (also known as prox reader and prox card). Encoded information is passed between the card and reader, usually supplying a unique pattern enabling identification of the cardholder.


A device a cardholder presents his access card to that will read the card's encoded data and transmit it to an access control unit (ACU). The ACU then make a decision as to what action to take as a result of that card read.

Request to Exit (REX)

A device used to disable a door alarm, thus allowing valid exit through an access controlled door. Usually a motion detector but can also be a push button.

Security Equipment Enclosure (SEC)

A cabinet or enclosure containing security equipment or controls.

Security Operations Center (SOC)

The central commanded center location where security personnel monitor and respond to security and safety related incidents.

Shear Lock

A type of magnetic lock installed flush in the head jamb of a door frame. The shear lock differs from a standard magnetic lock in that the holding force is based in the lateral -- or shear -- movement of the armature plate away from the lock body, rather than opposing tension direction.

Smart Card

A card containing a microchip that can store significantly larger amounts of data than a standard mag stripe or proximity card. Bank account details, Social Security Numbers and employee identification numbers are examples of data that can be stored on a Smart Card.

Storeroom Function

The type of lock function most often specified on access control doors.


Function lock is always locked from the unsecure side. If a key is used to open the door the lock set will always return to a locked state once the key is removed. This is referred to as a night latch by some manufacturers.


The electronic process of continually metering the integrity of an electrical circuit that connects signaling devices to a processing host panel. Supervision can measure up to 5 conditions and typically checks for shorts, open loops, and power failures.


Following an authorized and credentialed person through an access control point without having or using a separate valid credential.


A physical barrier device used to manage pedestrian traffic flow and access control at a security checkpoint.


A communication protocol widely accepted as an industry standard in the manufacturing of access control equipment. Wiegand data is typically the protocol used between the reader and the host panel.

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