Patent ID: 8073923

Claim:
A wireless network system comprising a plurality of terminal devices having a radio communication function, one of the plurality of terminal devices acting as a master device for controlling data transfer timing in a network, each terminal device other than the master device acting as a slave device performing data transfer with the master device under the master device's control, wherein each of the plurality of terminal devices includes: master device search programmed logic circuitry for searching for any terminal device acting as the master device and any terminal device acting as a temporary master device; temporary master process programmed logic circuitry for causing the terminal device to act as the temporary master device; switching programmed logic circuitry for, if the terminal device has not joined the network, performing a switching operation for alternately activating the master device search programmed logic circuitry and the temporary master process programmed logic circuitry; slave process programmed logic circuitry for, if the master device search programmed logic circuitry detects the master device's presence or the temporary master device's presence, causing the terminal device to act as a slave device for the detected master device or temporary master device; and master process programmed logic circuitry for, if another terminal device is detected as searching for the master device or temporary master device during a period for which the terminal device is caused by the temporary master process programmed logic circuitry to act as the temporary master device, causing the terminal device to act as the master device, wherein each of the plurality of terminal devices further includes master device disconnection determination programmed logic circuitry for, when the terminal device is acting as the slave device, determining whether the master device is disconnected from a network to which the terminal device belongs, and if the master device disconnection determination programmed logic circuitry detects that the master device is disconnected from the network, the switching programmed logic circuitry automatically starts the switching operation, and wherein each of the plurality of terminal devices further includes identification information storage programmed logic circuitry for, when a network is constructed with any other terminal device, receiving and storing identification information for identifying the other terminal device in the network, and the master device search programmed logic circuitry searches for any other terminal device, acting as the master device or acting as the temporary master device and has previously belonged in the network, based on the identification information stored in the identification information storage programmed logic circuitry.