COMMUNICATION DEVICE AND METHOD AND SYSTEM, AND MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a communication device and method that copes with a network fault by efficiently selecting a LAN or a public network and using the selected network and reduces the communication cost. SOLUTION: The communication device connected to the LAN 119 and the public network 118 is provided with a detection means that detects the presence of a fault in the LAN and with a changeover means that selects transmission via the LAN in prescribed timing of transmission data during data transmission via the public network. When the detection means detects the restoration of the fault in the LAN during the data transmission via the public network, the changeover means transmits data having not been transmission via the LAN.