| 摘要 |
PURPOSE:To prevent the situation that a sending data is thrown away due to collision by decreasing the polling interval of a master station than the minimum value of the retransmission wait time at collision possessed by each terminal station. CONSTITUTION:Suppose that a state change takes place in a supervision data at the side of a terminal station 2-1 on the way of the polling processing of the j2 and the change becomes a cause to start the supervision data random transmission to the master station. The terminal station 2-1 counts the carrier sense time from the end point of time of the polling processing #2. Since the polling interval tp is set shorter than the carrier sense time t1, the carrier sense does not reach the time t1 only and the signal of the next polling processing #3 is detected. Thus, the count of the carrier sense time is initialized to 0 again, the processings as above are repeated, and when the polling processing #N is finished finally, the supervision data random transmission of the terminal station 2-1 is performed after the wait time by t1 from the point of time.
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