Plain-language definitions

Glossary

Plain-language definitions for commercial cameras, alarms, access control, monitoring and video-storage terminology.

Access control

A system that manages who may unlock or pass through a controlled door, gate or other entry point.

Credential

A card, fob, PIN, mobile pass or other identifier presented to an access-control system.

DVR

A digital video recorder commonly associated with analogue or coax-connected cameras.

NVR

A network video recorder that receives and stores video from IP cameras.

PoE

Power over Ethernet, which can carry network data and electrical power over compatible cabling.

Retention

The period for which recorded video or event records are kept before overwrite or deletion.

Bitrate

The amount of data generated by a video stream per second, often measured in megabits per second.

VMS

Video management software used to view, administer and search one or more video systems.

Dual-path communication

An alarm communication arrangement using two independent paths, such as internet and cellular.

Request to exit

A device or input that allows or records authorized egress from a controlled opening.

Fail-safe lock

A lock arrangement that unlocks when power is removed, subject to the complete door design.

Fail-secure lock

A lock arrangement that remains locked from the secure side when power is removed while still permitting required egress.

Video verification

Use of associated video to help determine whether an alarm event appears genuine.

Variable bitrate

Video encoding that changes data rate according to scene complexity and movement.

Commissioning

The process of configuring, testing, documenting and accepting a completed system.