The use of computers in various control systems such as technical facilities, technological production processes, business management of companies, etc. is one of the basic characteristics of technological development in recent decades. The maintenance system of a modern elevator plant with microprocessor control should also be logically based on the use of computers, with specialist knowledge that is common to different areas and different professions. Microprocessor control groups have significant advantages over relay control groups from the point of view of elevator plant maintenance. Communication via telephone connection with the control and service center using a modem allows additional elevator control, diagnostics of operating and malfunctioning states of the elevator plant and adjustment of elevator plant parameters.