MASTER STATION COMMUNICATION DEVICE, SLAVE STATION COMMUNICATION DEVICE, AND NETWORK SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a network system which can reduce effects on the electrical continuity of a main signal even when a restart occurs in a master station communication device or a slave station communication device.SOLUTION: The present invention relates to a network system comprising one or a plurality of access networks having slave station communication devices connected to branched transmission lines and a master station communication device. The master station communication device comprises: one or a plurality of access network connection units for connecting to the access networks; and control means for controlling the respective access network connection units. The control means comprises: a first control processing unit which performs access network related monitoring via the respective access network connection units; and a second control processing unit which controls the respective access network connection units so that, even when a restart occurs in any of the access network connection units or the slave station communication devices, communication between the access network connection unit and the slave station communication device can continue.