| 摘要 |
PURPOSE:To prevent collision by awaiting transmission until no data is detected for a prescribed time when no data exists on a common bus and starting transmission synchronously with the data when the data is detected within a further prescribed time. CONSTITUTION:Both stations A, B start each timer from a point of time 0 when data on the common bus is lost to supervise a bus for a time from TfA, TfB to TpA, TpB, and when a signal is detected during that time, the data transmission is started synchronously with the signal immediately. If no signal is detected during that time, the data is transmitted after TpA, TpB are elapsed. If the clock of the station A, e.g., is slow, the station B starts transmission at the TpB, the station A detects the data of the station B and starts transmission synchronously and the station B stops transmission at a Tc by the priority. The station B stops transmission similarly at the Tc even when the clock of the station A is faster. Thus, collision on the bus is prevented and data with higher priority is transmitted.
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