A typical TV monitoring system consists of two parts: a front-end device and a back-end device. The front-end device is usually composed of a camera, a manual or electric lens, a pan/tilt, a protective cover, a monitor, an alarm detector, and a multi-function decoder. They perform their respective functions and establish corresponding connections (transmission of video/audio signals and control, alarm signals) with various devices of the central control system via wired, wireless or optical fiber transmission media. In the actual TV monitoring system, these front-end devices are not necessarily used at the same time, but it is indispensable to realize the camera and lens for monitoring live image acquisition. Back-end devices can be further divided into central control devices and sub-control devices.