Security camera
Capture images by transforming the visible scene observed by a camera lens into an electric signal to be processed. Often used as a means to deters criminal behavior.

Security monitoring
If you have activated your home security system and any of the home security sensors or detectors are set off, an emergency signal is transmitted either via phone lines, the internet or cellular towers to the central station. Upon receiving the signal, a trained professional will notify the appropriate authority.

Security system
An electrical device that sets off an alarm and notifies, residents, authorities and security center once a sensor is triggered such as in the case of a possible burglar, intrusion, fire, or other safety monitoring.

Spy camera
A hidden camera can be a still or video camera used to film people without their knowledge.

Surveillance system
Electronic devices used to maintain close observation of areas from a distance and without being seen.