| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission circuit for a communication signal in which a transmission state is surely detected and signal transmission is surely performed even if microcomputers or signal converters by different makers or of different types are used. SOLUTION: The transmission circuit comprises: three signal lines, of a signal ground line, S.G, an A side signal line, and a B side signal line; a plurality of computer means sending and receiving data signals: and a plurality of signal converters connected to each of the plurality of computer means through the signal lines. Each of the computer means detects the start and termination of data by finding that the data signals retain the H level for a specified period of time or longer to fetch the data. Each of the signal converters compares the voltage level of the A side signal line with that of the B side signal line to determine the H or L level of the data sent to the receiving side terminal of each of the computers. The A side signal line and the B side signal line apply resistance division to voltage between the H level and the L level and are always biased so that a potential difference may arise at a voltage in the intermediate range of the H level and the L level and between the A side signal line and the B side signal line. COPYRIGHT: (C)2004,JPO
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