In a CRT operation system for operation and monitoring of plant equipment in a plant worksite through a central control room and a network, an operation control personal computer is provided for monitoring and operating the plant equipment, and one or more wireless LAN transceivers or transmitting/receiving sections are provided to appropriate points in a patrol route around the plant equipment, for wireless communication with the operation control personal computer. The personal computer controls the plant equipment through a wireless transceiver and a network, and transmits therethrough information signals of on-site operation of the plant equipment to enable a display device and a sound/voice output device provided in the central control room.