| 摘要 |
PURPOSE:To attain complete duplex communication between two nodes possible by providing a controlling field that retains right of transmission in own node after giving right of transmission to other nodes in addition to a token frame that controls shifting of right of transmission between nodes. CONSTITUTION:Master nodes A, B and slave nodes C-D are connected in looplike form by a transmission line 6. A token frame is sent from th node A or B to nodes C-E, and a node that acquired the frame obtains right of transmission to the master node. Each node holds receiving frame in a receiving frame buffer 27, and address of receiving station DA, address of sending station SA, a level mask M and a controlling field C in the frame in registers 16, 18. DA', SA', M' set in registers 16-18 by a controlling processor 30 are compared by comparators 19-21. When all comparators coincide, and duplex communication right retaining bit of the sending station of the field C is decoded 22, an AND circuit 23 opens and latches token receiving, and executes duplex communication with the master by the transmitting frame held in a transmitting buffer 28.
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