| 摘要 |
Disclosed is an improved data communications system in which data porocessing apparatus having fiber distributed data interfaces provided with processing functions for synchronous services and asynchronous services are disposed at each node, and in which these nodes are connected via transmission paths into a ring shape and transmit and receive data. In such a system, the data processing apparatus for each of the nodes is configured from a transmission processor that governs the transmission control of the data, transceivers that perform the sending or receiving of data from the transmission path, a completion detection circuit that detects the send completion for own-station data or receive completion for data on the transmission path, a timer circuit that gives the timing of the data send cycle to the transmission processor, a dual-port memory that temporarily stores the data received from the transceiver, a common memory that stores this data to a corresponding memory address on the basis of the address in the data which is the object of send or receive, a direct memory access circuit that transmits the received data stored in the dual port memory circuit to the common memory, and a control circuit that classifies the data that has been renewed between the equipment connected to the data processing apparatus of each of the nodes, into a plural number of levels in accordance with its degree or urgency, allocates it as data having a unique address on the common memory set so as to have shared address for each of the data processing appaatus, sets a plural number of shared renew cycles in each of the data processing apparatus and corresponding to the data of the plural number of levels, makes relationships between these renewed cycles and the processing functions for the synchronous services and the asynchronous services, and controls the transmission of data so that the renewed cycles that are related to the synchronous services and the asynchronous services are the time cycles corresponding to the data of each of the levels. |
