The system called ANDON informs workers of malfunction of equipment, delay in operation and other abnormalities with display lanterns in automobile parts production line and it is widely utilized in TOYOTA. To make this system operate more effectively, a new network which handles many on-off signals that show the malfunction and other operating conditions of equipment in all areas of the plant is developed. The network can link terminals that send or receive signals, programable controlers and computers freely by using twisted paired cable which is 5 km long, and the signals for a maximum 4 000 items can be transmitted in one second. The developed network reduces the cost of ANDON system by 27% and is capable of facilitating addition and change of signals. Also, an equipment management system that links to this network is developed. This system in capable of monitoring the stopping time of the equipment by causes. This system is composed of interface which receives ANDON signals from the network, 8-bit microcomputer which detects the state of equipment and 16-bit personal computer which preserves the data. By the improvement of the production by utilizing this system, it become possible for us to increase the production volume.