| 摘要 |
PURPOSE: To reduce the power consumption by supplying power to plural transmission modules in a circuit network so that lower one of voltage levels of two lines correspond to short-circuit due to one of these modules and higher one corresponds to the break state in asynchronous transmission standards. CONSTITUTION: Several modules 14, 16, and 18 are arranged in the whole of a building. Binary data transmitted through symmetrical two-wire circuit networks 10 and 12 for asynchronous binary data transmission is modulated by two voltage levels of two lines. Lower one of these voltage levels corresponds to short-circuit due to one of modules 14, 16, and 18 of circuit networks 10 and 12, and higher one corresponds to the break state of asynchronous transmission standards to supply the power to modules 14, 16, and 18, and power is supplied to modules 14, 16, and 18 from a battery device 34 if circuit networks 10 and 12 are short-circuited.
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