| 摘要 |
PURPOSE:To secure the synchronization of time among plural devices based on the time of another device even if the reference time given from a master device is interrupted by providing the function of the master device to a precedent device and shifting the master function to another normal device when the master device has a fault. CONSTITUTION:A master device is defined among plural devices 12 such as a facsimile, a switchboard, a display device, etc., which contain the information processing functions and are connected to a data highway 11 serving as a data transmission line. Then the time of a clock circuit 14 of each device 12 except the master one is synchronous with the reference time of the circuit 14 of the master device 12. When the reference time of the master device 12 has a big error to the average time of other devices 12, a wrong reference time is decided and then corrected to the average time. If the master device 12 has a trouble, another normal devices 12 substitutes for the faulty master device. As a result, the synchronization of time is always secured among the circuits 14 of devices 12. |
