RING-TYPE SUBORDINATE SYNCHRONOUS NETWORK AND SUBORDINATE SYNCHRONOUS METHOD

摘要

PROBLEM TO BE SOLVED: To prevent occurrence of the loopback of clock signals and the synchronous defective slave nodes by securing such a constitution, in which the slave nodes monitor the states of the clock signals under selection to notify a master node of the monitoring results and the master node gives all at once the clock selection instruction to the slave nodes. ;SOLUTION: A clock-monitoring circuit 23 notifies a master node M of the states of clock signal under selection via a clock state signal ALMO/1. If a clock signal C0 is normal when the clock signals under selection belong to an 0 system, a clock state signal ALMO is set at 1 and notifies. If the signal C0 is not normal, the signal ALMO is set at 0 and notified. The master node refers to the clock state signals collected from every slave node and sends a clock selection signal SELO/1 to every slave node. It is decided that a fault occurs on a transmission line of the 0 system, when a clock state signal ALMO 0 is received from the 0 system. Thereby, an instruction is produced to switch the signals C0 of the 0 system to the clock signals C1 of a 1 system all at one.;COPYRIGHT: (C)1998,JPO