| 摘要 |
PROBLEM TO BE SOLVED: To provide a remote automatic metering system for gas supply or an electric supply that requires no new cable installation interconnecting inside and outside of subscribers, even when an analog telephone line is switched into a digital telephone line network. SOLUTION: A 1st multiplex controller 11 is inserted to a subscriber line 3 at a subscriber's home for connection to an I-NCU 9, a 2nd multiplex controller 21 is inserted to a subscriber line 3 at the outside of a sucscriber's home connection to a metering meter 5, and the 1st and 2nd multiplex controllers 1, 21 conduct data transmission reception by causing a signal to superpose on the subscriber line 3. Since a line voltage is fluctuated by turning on/off switching elements 13, 23 provided between the two wires of the subscriber line 3 in response to data to be transmitted, voltage detectors 14, 24 detect the line voltage fluctuations with a low frequency to restore original data.
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