PURPOSE: To eliminate the need for a maintenance personnel to enter the number or kinds of communication nodes frequently changed due to the node increase/ decrease installation work to a management node.

CONSTITUTION: A management node D sends a communication node number notice command signal in terms of multiple address at first at the rising of a communication network, and communication nodes A-C receiving the communication node number notice command signal return its own node number to the management node D and the management node D receiving the number decides a management communication path ID for each communication node, the management communication path ID is sent to the communication nodes A-C in terms of multiple address communication by using a management communication path ID notice signal, and each of the communication nodes A-C receives the management communication path ID notice signal to latch the management communication path ID of its own node.