| 摘要 |
PURPOSE:To improve the response performance and continuity in controlling terminal devices from a central processing unit by designing the system that the central processing unit not only decides the propriety to an inquiry signal from a terminal device but also uses an acknowledgment signal to inform the control desired by the processing unit to the terminal device. CONSTITUTION:Start signals B, C, D and a reset signal A different from them are transmitted from the central processing unit 10 to the terminal device 11 to reset a control inquiry counter. The unit 10 transmits the start signal B to the terminal device 11 to increase the counter and the device 11 uses the count as an inquiry signal to transmit it to the unit 10. The unit 10 checks the inquiry signal and when it implies no desired control, the unit 10 transmits again the next start signal. When the inquiry signal H from the terminal device 11 is desired control for execution, the unit 10 transmits an acknowledgment signal E, under which the terminal device 11 executes the said control.
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