| 摘要 |
PURPOSE:To send a message to a master station with a fewer number of times of re- transmission when the collision of the message from a mobile body occurs in the master station by stopping the sending of a second transmission frame from a station other than another station until detecting a reception confirmation signal for the another station when the address of another station and a re-transmission request signal are issued. CONSTITUTION:When the master station receives a transmission frame from a slave station and detects an error, the reception confirmation signal is transmitted to a corresponding slave station if no error exsts in both the address and data, however, the re-transmission request signal is transmitted if the address is correct and the error exists in the data, and no transmission is performed if the errors exist both in the address and the data. Meanwhile, the slave station, when receiving the re-transmission request signal addressed to its own station, forms the transmission frame of prescribed frame format and retransmits it, however, when the signal is the re-transmission request signal addressed to another station, the transmission of the slave station other than another station is stopped until the reception confirmation signal is transmitted to the slave station to which the re-transmission request signal is transmitted. Thereby, the message can be sent to the master station with a fewer number of times of re-transmission when the collision of the message from the slave station occurs in the master station. |
