(As the terminal equipment of the closed-circuit monitoring system, the monitor often encounters various technical problems in the process of engineering use (design, installation and commissioning), and some of these problems are caused by problems such as the coordination with the front-end equipment, wiring process, rationality of grounding, etc; Some are caused by not knowing the technical performance of the monitor itself; Of course, it may also be caused by the problem of the monitor itself. This article will communicate with readers some technical problems often encountered in the use of monitors.)