LINE CONNECTION DEVICE AND COMMUNICATION SYSTEM

摘要

A communication system includes: a trunk line; a plurality of branch lines; a control device (a parent station) connected to the trunk line; process devices (child stations) respectively connected to the branch lines; and a line connection device which connects the branch lines to the trunk line by the multi-drop format. Upon detection of a communication error, the control device (parent station) successively disconnects the line connection device from the branch lines. By monitoring a communication error during the successive disconnection, the control device judges whether a branch line has failed and causes the line connection device to disconnect the branch line which has failed.