| 摘要 |
PURPOSE:To realize a multidrop connection for the stations in different speeds of communication with the same transmission line, by providing an unlocked state under which the transmission control information is transmitted and received and a locked state under which the information data is transmitted and received for the transmission line. CONSTITUTION:When a transmission line L is unlocked, a control data for request of communication start is transmitted to a station from a communication processing part (h) of a host system H. Thus the part (h) locks the line L if a confirmation answer control data which is given from the station in response to the above-mentioned request control data can be transmitted. However the line L is kept unlocked if the communication unable signal is transmitted from the station. In case the line L is locked as mentioned before, the part (h) performs the transmission and reception of the information data in response to the communication speed of a specified station. |
