Patent ID: 8369308

Claim:
A remote I/O system comprising: a master node and one or more I/O nodes connected to a wireless LAN through a wireless LAN access point, wherein the master node comprises: a clocking means for indicating a current time; a beacon recognizing means for detecting a reception of a beacon that is sent from the wireless LAN access point to the master node and the one or more I/O nodes; a time detecting means for determining a time stamp indicating when the reception of the beacon is detected by said beacon recognizing means based on a time indicated by said clocking means; a master list generating means for generating a master list that is a list of the time stamp; and a master list sending means for sending the master list containing the time stamp to the one or more I/O nodes through the wireless LAN access point, wherein the beacon includes a TSF timer value for identifying the beacon, and the master list contains the TSF timer value of the beacon corresponding to the time stamp indicating the time of said clocking means that is contained in the master list.