| 摘要 |
PROBLEM TO BE SOLVED: To enable the PON counter of a terminal device to synchronize correctly in a PON system in which up signals sent from a terminal device to a central terminal are subjected to time division multiplexing. SOLUTION: The PON system is provided with a central terminal 1, an optical fiber network 10 having a configuration in which an optical fiber 5 connected to the central terminal 1 is branched into optical fibers 7, 8, and 9 through the intermediary of an optical coupler 6, and terminal devices 2, 3, and 4 connected to the terminals of the branched optical fibers 7, 8, and 9. Up-signals sent from the terminal devices 2, 3, and 4 to the central terminal 1 are subjected to time division multiplexing. The PON counter of the terminal devices 2, 3, and 4 is subjected to drift adjustment so as to lessen a time lag between a time stamp TS and the PON counter, at a point of time when the time stamp TS contained in the control frame of down-signals is sent; and the transmission timing of up-signals is determined on the basis of the adjusted PON counter. COPYRIGHT: (C)2007,JPO&INPIT
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