Central monitoring equipment that monitors and records equipment automation and malfunctions for air conditioning, production, electrical, water supply and drainage facilities is an indispensable system in this age of unmanned facilities. Monitoring controller PLCs, which monitor multiple facilities, often have multiple wires and are prone to lightning surge damage. In addition, if the central monitoring device is damaged, the real-time situation at the site becomes unclear, and there is concern that action may be delayed. Also, if multiple buildings or facilities are being monitored, they are more susceptible to lightning surges. During the replacement of the central monitoring PC or monitoring controller PLC, the situation at the site may become unclear, which may lead to a secondary disaster.