| 摘要 |
The method provides an effect of protection by insertion of telephone terminals in a terminal device without open-closure of the terminal device cover. The method includes a terminal device (10) which outputs correction value to an exchange interface, a handler (20) which reads meter value and states by specific lines (L1)(L2), and a telephone line code (40) which connects a terminal (10) to a handler (20). The handler (20) includes a signal detection unit (21) which detects a loop signal according to a photo coupler (PT1), a hook state detection unit (22) which determines hook states by a resistor (Rf) and an earth condenser (Ct), and a ring detection unit (23) which detects a ring signals according to a diode (D1), a capacitor (Cs) and a resistor (R5).
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