| 摘要 |
PURPOSE:To attain a data transmission system which is free from the occurrence of undesired collision of data by securing such a constitution where the transmitter of the transmitter side sends the post-ambles continuously to a transmission data frame and the transmitter of the receiver side transmits the prescrined data after detecting a reception error to inform the data reception error. CONSTITUTION:A transmission buffer 2 stores those data on the frame control 152 through the frame check sequence FCS156. A transmission control circuit 3 checks whether or not a carrier detecting circuit 8 detects a carrier out of a communication medium 12. Then the circuit 3 outputs a pre-amble transmission request to a pre-amble generating circuit 4 after confirming that no carrier is detected, i.e., the medium 12 has the idle information. Then the circuit 4 transmits a pre-amble 151 onto the medium 12 via a transceiver 6. Then it is checked whether or not a collision detecting circuit 7 detects a collision. If the occurrence of the collision is confirmed, the transmission of data is discontinued for a fixed time decided by the back-off algorithm. Then a post-amble generating circuit 5 transmits again a data transmission frame after a prescribed time is elapsed.
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