| 摘要 |
PURPOSE:To improve the reliability in a star type line network by duplicating a repeater and using a low-order port of a repeater on standby as an extension port. CONSTITUTION:Setting switches S1a, S1b so as to connect incoming lines 50a, 50b on the standby state which are connected to the high-order node to collision detection sections 20a, 20b of a repeater to be connected, the line from the low-order ports 12a, 12b of the repeater in the standby state is concentrated to detect the collision of frames. Since collision detection sections 20a, 20b detect collision from the state change of each line, frames ORed by a repeater cannot be detected whether or not the frames are in the collision state, and the collision detection signals are ORed. Since a signal from the host device is distributed as it is in the outgoing lines 52a, 52b, they are connected directly. In order to constitute the connection, the repeaters are connected by connectors 21a, 21b and the repeater is switched by a line with the high-order node and the low-order ports 12a, 12b are used as extended low-order ports and the duplication of the part except collision detection sections 20a, 20b is constituted.
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