| 摘要 |
PURPOSE:To apply communication controllers to a system requiring the real time processing by preferring transmission from a succeeding communication controller to that from its own communication controller to a repeating circuit if data collide on a transmission line. CONSTITUTION:If a communication controller 4d transmits data after a communication controller 4a transmits data, a receiving part 42 in the communication controller 4a detects data transmission from the communication controller 4d, and simultaneously, a gate 45 connected to a transmitting part 43 is turned off by a data reception detection signal S to stop the output from its own communication controller 4a. Thereafter, the communication controller 4a monitors a flow of the data packet signal of the communication controller 4d and adds a transmission holding mark to the last of the data packet signal of the communication controller 4d together with its own address of the communication controller 4a by a transmission holding mark adding part 46. Thus, communication controllers can be used even in the system requiring the real time processing.
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