To improve communication efficiency, avoiding the collision of signals, as much as possible, even when normal state needs to be changed into a transition state.

A communication timing control device, which is located at each of nodes that constitute a communications system, decides the transmission timing of communication timing signals from its own node, using the receiving timing of communication timing signals from the other node, determines a time slot through which data signals are transmitted from own node, on the basis of transmitting timing and receiving timing, and determines whether the communication system is in normal state or in transition state. The communication timing control device is equipped with a determination means which determines whether it is required, to enable an adjacent mode to recognize that it is in a transition state, when the communication system is in a normal state, and a means of moving transmission timing from own node to a timing position, at which the adjacent node is capable of detecting the communication timing from own node, when it is determined that it needs to enable the adjacent node to recognize that it is in a transition state.

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