| 摘要 |
PURPOSE:To prevent securely data from being mixed by comparing data of a data input line with that of the data output line of a terminal whenever one bit is outputted during at least one byte outputting period and stopping the output of data when a difference can be found. CONSTITUTION:When two units of terminals supervise a host RXD input line in order to output data, there is the timing when terminals T2 and T3, for instance, output simultaneously data, recognizing that the time of the same one byte is in the MARK state. In such a case at least initial one byte of the data output of each terminal shows an equipment number inherent to each terminal as a number or character, and during the output data of an RXD line is compared with that of the TXD output line of the terminal itself whenever one bit is outputted. When a difference is found, the output of data is stopped. Therefore the terminal T2, which outputs the signal of SPACE at the bit where the difference is found, continues its outputting as it is. Then the terminal T3 outputting the signal of MARK stops its outputting, thereby preventing the data from being mixed.
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