CCTV (closed-circuit television) is a TV system in which signals are not publicly distributed but are monitored, primarily for surveillance and security purposes.

CCTV relies on strategic placement of cameras, and observation of the camera’s input on monitors somewhere.

In the field of physical security, access control (AC) is the selective restriction of access to a place or other resource.

The act of accessing means entering. Permission to access a building is called authorization.

Anti-climb weld mesh system (also known as 358 mesh fencing) is dominantly used in fencing systems designed to bring maximum perimeter protection to a site without impeding visibility (which is important for human patrolling or video surveillance).

The high density, high tensile mesh includes apertures too narrow for finger and footholds, preventing climbing or cutting with standard tools, bolt cutters etc.

A security alarm is a system designed to detect intrusion /  unauthorized entry into a building or area.

Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders.

An intercom (intercommunication device), talkback or doorphone is a stand-alone voice communications system for use within a building or small collection of buildings, functioning independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles

Structured cabling systems for voice, data security and video.