| 摘要 |
PURPOSE:To attain high speed processing by storing the state of each terminal device connected to a station, by always holding said state at a terminal state storing buffer of the station, to recognized said state without awaiting the response from the said terminal device. CONSTITUTION:A buffer B13 storing the state of a terminal device is provided to a station ST12 connected to a loop form transmission line 1. The ST12 does not send a data 8 incoming from the upperstream to a controllder IOC7 of the terminal device but stores it in a buffer 13, writes information of a terminal device IO4 to the X part of the data 8 and transmits the result as the Y part of a data 9 to be fed to the downstream. When the CPU of the ST transmitting the data sets an operation command to obtain information to a CMD section and transmits the result, then each ST outputs the stored information while superimposing it on the data part when the data is addressed to the own station and the CMD part is the terminal information request command. The CPU obtains the information of the terminal device when the data outputted from itself returns circularly through the transmission line. |
