Security monitoring system uses optical fiber, coaxial cable or microwave to transmit video signals in its closed loop and to take pictures from it.To the image display and recording constitute an independent and complete system. Security monitoring system is based on optical fiber, coaxial cable or microwave.The closed loop transmits video signals and forms an independent and complete system from camera to image display and recording.It can reflect the monitored object timely, vividly and truthfully. It can monitor for a long time instead of manual work in harsh environment.Recorded by video recorder.