| 摘要 |
A half-duplex communication control method according to this invention is constructed so that in a half-duplex communication control method in which two devices connected by two signal lines are had and half-duplex communication in one-to-one correspondence is conducted, the first device outputs a sending request output for providing notification of a state of a communication request to the second device as a sending request signal using an open collector buffer and also turns back its sending request output inside the self device to check a communicable state as a sending request input and also in the case of being receivable with respect to the sending request signal sent from the opponent device, the second device outputs a sending permission output for providing notification of a communicable state to the first device as a sending permission signal using an open collector buffer and also turns back its sending permission output inside the self device to check a communicable state as a sending permission input, and since each the device decides sending permission by an output from the opponent device, sending is performed after checking whether the opponent device is receivable, so that both the devices are prevented from starting sending simultaneously.
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