The main purpose of the CCTV system is for monitoring different areas like banks, resident area, casino, airport, military base, school campus, police stations, and convenience store, etc.
For commercial usage, CCTV systems can be used for monitoring different district area If there is some restricted area that is not applicable for real person monitoring, the CCTV systems can help to monitor anytime.
In the early development of CCTV systems, videotapes are used as the recording media. In recent year, it has been changed into single or multiple hard discs as the recording media. Nowadays, the CCTV system transforms into a new format, which is used Digital Video Recorder to record large storage of images with high resolution. Those images can be used for saving as future use or even can provide to court as evidence once if needed. As the technology becomes more mature, CCTV can also have real-time monitoring by mobile devices through the Internet.