| 摘要 |
PROBLEM TO BE SOLVED: To provide the subscriber line test device and the test method where the normality of line is tested without installing line test exclusive devices such as a measurement device and an adaptor to draw a line up to the measurement device to an exchange system. SOLUTION: A line monitor resistor R with a high resistance branched from a line LN and an arithmetic section EP are provided in a line circuit LC. A ground voltage of the line LN is measured by terminal voltages VrefR, VrefT of the line monitor resistors R, and given to the arithmetic section EP. In the case of on-hook, the arithmetic section EP detects induction of an AV voltage in the line LN and unbalance of a DC voltage based on the monitor of the voltages VrefR, VrefT for a prescribed time to obtain a line resistance. Furthermore, in the case of off-hook, the line resistance of the line LN is obtained by using a difference between a theoretical value of the voltages VrefR, VrefT when the line is open and silent and a correction value in a silent state when the voice component is eliminated.
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