Name a common type of surveillance system used in physical security.

Closed-Circuit Television (CCTV) is widely recognized as a fundamental component of physical security systems. It involves the use of video cameras that transmit signals to a specific, limited set of monitors. This allows security personnel to visually monitor specific areas in real time or review recorded footage for incident investigations.

CCTV systems are beneficial because they can deter criminal activity by increasing the perceived risk of being caught, enhance situational awareness, and assist in monitoring complex environments—ranging from retail spaces to parking lots—and sensitive areas such as banks or government buildings. The visual confirmation that CCTV provides can be crucial in validating the occurrence of events and gathering evidence when incidents do occur.

While other options like infrared sensors provide important functions in security—primarily related to detection—CCTV systems stand out for their ability to provide detailed visual documentation, which is paramount in many physical security applications. Techniques like virtual reality monitoring and smartphone applications are emerging technologies; however, they do not yet match the widespread use and established effectiveness of traditional CCTV surveillance in physical security practices.