| 摘要 |
PURPOSE:To attain simple control without the necessity of output of a useless occupied instruction by outputting the occupied instruction when a holding means does not occupy other communication medium. CONSTITUTION:A CPU 15 supervises transmission data on the 1st transmission line 11 via a transmission line interface 14 to supervises whether or not a transmission frame addressed to the own node being an address value set to an address set section 21 for a destination address in the transmission frame is received. When the own node destination transmission frame is received, whether or not the transmission frame is a token frame is checked. When the token frame is received, whether or not the occupancy request of the 2nd transmission line from various equipments 19 exists is checked. The various equipments 19 receiving the information of the occupancy of the 2nd transmission line apply transmission preparation and when the connection with the 2nd transmission line 12 is finished, data is communicated with a desired station. When the communication is finished, the 2nd line transmission line occupancy request signal to the node 13 is reset. On the other hand, when no occupancy request to the 2nd transmission line 12 exists, the connection between the 2nd transmission line 12 and the various equipments 19 is disconnected.
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