| 摘要 |
PURPOSE:To attain answer back simply without complicating the constitution of a slave station by providing a start and stop bits to at least a control data only and returning the data when a receiving terminal receives the control data from a control station. CONSTITUTION:Information shown in Fig. A is transmitted from the control station 2, a slave station 1 is brought into the initial state by the start signal ST and the address is collated by the next address signal. Then, the command signal is discriminated, and a data is read via an input section 18 at the information collecting mode and transmitted to the control station via a common signal line (l). The start ST and stop SP bits are added to the control data in the transmitted signal form as shown in Fig. B. When the command signal represents the control mode, the control station transmits continuously the same data twice. Only when the collating circuit 16 receives it, the said data is latched to the circuit 17 and outputted to an external device and returned. The signal form in this case is as shown in Fig. C and the start ST and the stop SP bits are added to the existing control output data of the circuit 17. |
