34 terms explained
AAccess controlCredentials, controllers
CCamerasIP, PTZ, LPR, VMS
NNetworksPoE, fibre, VLAN
Security system glossary
Plain-language definitions of the access control, camera, intercom, alarm and network terms you’ll hear when planning a security system.
Updated
Terms A to Z
34 terms, explained simply. Updated October 2, 2026.
- Access control
- A system that controls who can open which doors, when, using credentials like fobs, cards or phones. Learn more
- Access point (Wi-Fi)
- A device that broadcasts Wi-Fi. Larger buildings need several, placed so coverage reaches every area. Learn more
- Alarm monitoring
- A monitoring centre that watches your alarm 24/7 and follows your response plan when it goes off. Learn more
- Anti-passback
- A rule that stops one credential from being used to enter twice without exiting, so a fob can’t be passed back to let someone else in. Learn more
- Cat6
- A common type of copper network cable, good for runs up to 100 metres. Learn more
- Cellular communicator
- A device that sends alarm signals over the mobile network instead of a phone line or internet connection, so the alarm still reports if those fail. Learn more
- Cloud-managed access control
- Access control run from a web browser or phone app, with the software hosted by the maker instead of on a server in your building. Learn more
- Controller
- The device that decides whether a door should unlock when a credential is presented, and logs every event. Learn more
- Credential
- Anything a person uses to prove who they are at a door: a fob, card, phone, PIN or face. Learn more
- Door forced and held-open alarms
- Alerts when a controlled door is opened without a valid credential, or is left open longer than allowed. Learn more
- DVR
- Digital video recorder: records video from analog cameras over coaxial cable. Most new systems use IP cameras and an NVR instead. Upgrading from a DVR
- Electric security fence
- A fence that gives a sharp, non-lethal pulse to anyone who touches it, carries warning signs and sends an alarm if it’s cut or shorted. Learn more
- Electric strike
- A lock part that replaces the strike plate in a door frame and releases electronically, so the door can open. Learn more
- Elevator control
- Access control that limits which floors a person can reach with their credential. Learn more
- Enterphone
- A long-running brand of apartment entry intercom. Many people use the name for any phone-line buzzer at a building entrance. Replacing an Enterphone
- Fail-safe vs fail-secure
- Fail-safe locks unlock when power is lost; fail-secure locks stay locked. The right choice depends on the door and code requirements. Learn more
- Fence intrusion detection
- Sensors mounted on a fence that detect climbing, cutting or lifting and report which zone was hit, often triggering cameras, lights and a siren. Learn more
- Fibre
- Network cable that carries data as light, used for long runs and links between floors or buildings. Learn more
- Glass-break sensor
- An alarm sensor that listens for the sound of breaking glass. Learn more
- Infrared (IR)
- Light invisible to people that cameras use to see in the dark. Learn more
- IP camera
- A security camera that sends video over a network, rather than over older analog cable. Learn more
- License plate recognition (LPR)
- Cameras and software that read vehicle plates and keep a searchable log. Learn more
- Lockdown
- Locking selected doors at once from software, a button or an app, for example in a school or office during an emergency. Learn more
- Maglock
- An electromagnetic lock that holds a door closed with a magnet while it has power. Learn more
- Mobile credential
- A phone or smartwatch used as a credential instead of a fob or card. Learn more
- Multi-sensor camera
- A camera with several lenses in one housing, covering a wide area from a single mount. Learn more
- Muster system
- A system that tracks who is on site and who has reached a muster point during an evacuation, so roll call is fast and accurate. Learn more
- NVR
- Network video recorder: a device that records and stores video from IP cameras. Learn more
- OSDP
- Open Supervised Device Protocol: a newer standard for how card readers talk to door controllers, with encryption and tamper monitoring. It replaces Wiegand. Learn more
- Parcel locker
- A bank of secure lockers where couriers drop packages and recipients pick them up with a code. Learn more
- PoE (Power over Ethernet)
- Sending power and data over one network cable, which is how most IP cameras and many readers are powered. Learn more
- Point-to-point wireless link
- A pair of radios that connects a second building, a gate or a camera pole to the network without trenching cable. Learn more
- Proximity card (125 kHz)
- An older type of fob or card that’s easy to copy. Many buildings are replacing them with encrypted credentials. Learn more
- PTZ camera
- Pan-tilt-zoom: a camera that can turn and zoom to follow activity across a large area. Learn more
- Remote video monitoring
- A monitoring team watching live alerts from your security cameras, warning people off through speakers and calling police or your contact when a threat is real. Learn more
- Request to exit (REX)
- A sensor or button that tells the access system someone is leaving, so the door releases without an alarm. Learn more
- Smart card
- An encrypted card or fob, such as HID Seos, that is far harder to copy than older proximity cards. Learn more
- Solar-powered camera
- A camera that runs off a solar panel and battery, usually with a cellular connection, for yards and sites without power. Learn more
- Structured cabling
- An organized, labelled and documented cabling system that supports a building’s network. Learn more
- System rescue
- When a new provider takes over, repairs and supports a system another company installed or left unfinished, including admin access and documentation. Learn more
- Tailgating
- When someone follows an authorized person through a door without using their own credential. Learn more
- Talk-down speaker
- A speaker beside a camera that lets a monitoring operator warn someone on site in real time. Learn more
- Thermal camera
- A camera that sees heat instead of light, so it can detect people and vehicles in darkness, smoke or fog. Learn more
- Video analytics
- Software that detects people, vehicles or unusual activity in video, so alerts and searches are smarter. Learn more
- Video intercom
- A door station that lets visitors call residents or staff, who see them on video and can unlock the door. Learn more
- Video management software (VMS)
- Software for viewing, recording and searching video from many cameras, like Genetec or Milestone. Learn more
- Video verification
- Using camera footage to confirm an alarm is real, so responders know it’s a genuine event. Learn more
- Virtual key
- A time-limited digital pass sent to a guest’s phone for entry. Learn more
- VLAN
- A separate virtual network on the same equipment, often used to keep security devices apart from office or guest traffic. Learn more
- Wiegand
- An older wiring standard between card readers and controllers. It’s common but unencrypted, which is why newer systems use OSDP. Learn more
- Zone (alarm)
- An area or group of sensors an alarm system arms, disarms and reports on separately. Learn more
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