| 摘要 |
PURPOSE:To simplify communication control by using the combination of plural control signals to manage a sequence number corresponding to a transferred data block thereby minimizing the quantity and time of data retransmission due to parity error detection of reception data. CONSTITUTION:Data communication equipments 10, 20 of an asynchronous start- stop data communication system are connected by data lines 31, 32, display signal lines 41-44 for state management, sequence number display lines 51- 54 and a retransmission signal line 61. A transmission request signal, a transmission enable signal and each ready signal of the signal lines 41-44 are managed respectively by state management sections 14, 24 connected to CPUs 11, 21. Further, sequence number management sections 15, 25 of a data block connected to the CPUs 11, 21 manage a sequence number corresponding to the data block. Then the data quantity and time at data retransmission from the signal line 61 because of parity error detection of reception data are minimized to a required value to simplify the system constitution. |
