| 摘要 |
PROBLEM TO BE SOLVED: To provide a reliable road management system capable of being backed up, even in a failure of a relay device, by another relay device. SOLUTION: In this system, a plurality of relay devices 103a and 103b for connecting a plurality of electric room networks 105a and 105 to a roadside network 102 are provided with connection definition tables 109a and 109 in which connection permission addresses and input and output commands are defined, respectively. When a failure occurs in either one of the relay devices 103a and 103b, the connection definition table of the relay device with the failure is transferred to the other relay device, whereby the monitoring control governed by the relay device with the failure is carried out by the other relay device. COPYRIGHT: (C)2004,JPO
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