Patent ID: 6987776

Claim:
A multiplex communication method comprising: determining a transmitting node obtaining a data transmission right based on a token circulated among a plurality of nodes; transmitting data by specifying another specific node as a transmission destination from the node obtaining said data transmission right; obtaining clock information by the node having said data transmission right; and adding the obtained clock information to the data to be transmitted; determining a clock master for providing a reference clock information in advance among said plurality of nodes; transmitting data including the reference clock information by said clock master; receiving the reference clock information within the data transmitted from said clock master by nodes other than said clock master; comparing an internal clock information of an internal clock of the node that receives the reference clock information with the reference clock information; slightly advancing, slightly retarding or keeping the internal clock as is, when a difference between the internal clock information and the reference clock information falls within a certain allowance; and updating the internal clock information to the reference clock information, when the difference between the internal clock information and the reference clock information does not fall within the allowance.