A basic security audit should be conducted in order to determine whether a surveillance system is needed, and, if so, how it should be designed. If a surveillance system is recommended on the basis of the security audit, then the first step is to gain a knowledge of how the surveillance equipment operates. This article describes the components and technology of a typical system that provides monitor observation of all camera views from a central location. Detailed descriptions are provided for camera layout and design, switchers (allows switching between multiple cameras) and multiplexers (allows recording and displaying images of all cameras simultaneously). The article also explains the two current general recording processes; the first uses a video cassette recorder, and the second records onto a digital recorder. The article provides descriptions of the following types of surveillance layouts: cameras located in long corridors, cameras at exits, and cameras grouped at corridor intersections. This is followed by a discussion of the use of consultants.