| 摘要 |
PROBLEM TO BE SOLVED: To eliminate erroneous discrimination of a line class to which a subscriber device to be investigated subscribes, even if "unconditional transfer" is set in the subscriber device to be investigated. SOLUTION: A control section 10 makes a nonrestrictive digital call to a subscriber device to investigate a line class via a nonrestrictive digital signal transmission section 13 and a terminal adapter 14. A response analysis section 17 analyzes reaction to the nonrestrictive digital call and based on a result of the analysis, the control section 10 discriminates whether a line of the subscriber device can be determined as a digital line or can be an analog line. If it can be an analog line, the control section 10 originates a call to a automatic busy investigation service center 40 via a DTMF signal generation section 15 and a modem 16. A voice recognition section 18 recognizes guidance voices from the automatic busy investigation service center 40 and discriminates whether the communication line of the subscriber device can be determined as an analog line or can be determined that the discrimination is impossible. COPYRIGHT: (C)2007,JPO&INPIT
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