| 摘要 |
PURPOSE:To reduce the reception waiting frequency of a transmission disabled apparatus and to suppress the delay of transmission with a normal apparatus at its minimum by forming a control means for successively reducing the transmission request frequency to a slave apparatus for the transmission disabled transmission system. CONSTITUTION:The initial value '0' is entered into respective memory element 9-1, 9-2, 10-1, 10-2 of memories 9, 10 under control by an I/O control circuit 8 to initialize these memory elements 9-1, 9-2, 10-1, 10-2. Then, the contents of the memory element 9-1 are read out and whether the contents are '0' or not is decided by a comparator 11. When the contents of the memory element 9-1 are not '0', transmission inhibiting status to the 1st apparatus 5 is decided and '1' is subtracted from the contents of the memory element 9-1 to check the transmission of the 2nd apparatus 7. If the contents of the memory element 9-1 is '0', a transmission request to the 1st apparatus 5 is transmitted to wait a response from the 1st apparatus 5. If no answer can received after the passage of a fixed period, '1' is added to the contents of the memory element 10-1 and the added contents are transferred to the memory element 9-1. When the answer is received, the contents of the memory element 10-1 is set up to the initial value '0'.
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