| 摘要 |
PURPOSE:To reduce load on a program and to perform communication control, by providing a guarantee circuit which performs the timing control to cut off a dummy data generation circuit and an RS signal (transmission request) in a communication control circuit which cuts off the RS signal after the lapse of the guarantee time of final data after completing the transmission of transmission data. CONSTITUTION:A program is executed so as to set the content of a guarantee type on a guarantee type register 42a in advance. When the transmission of one telegram is completed, the program, after delivering the final data to a transmission data buffer 41, cuts off 1 the RS control signal SRS of an input register 40 via a bus BUS. A final data guarantee circuit 42b sends the final data by cutting off the RS control signal SRS of the input register 40, then, performs an operation based on the content of the guarantee type register 42a set in advance, and at a time when the operation is completed, cuts off the RS signal to a line terminating device, In such a way, the load is reduced and data communication with more efficiency by performing the preparation of the data to be transmitted at next.
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