| 摘要 |
PURPOSE: A preventer for a false use of a public phone is provided to prevent the false use by operating a dial pulse of the public phone, so that a charge leakage of the public phone can be prevented, The preventer is provided to recognize general managers for reliability of charging in executing a card phone, so that a self-supply can be activated. CONSTITUTION: A preventer for a false use of a public phone comprises a call circuit(12), a dial tone multiple frequency(DTMF) detector(15), and a title circuit(18). The call circuit(12) forms a speech path with an exchange office, and cuts the speech path when receiving a control of the title circuit, and decided to be an abnormal call. The DTMF detector(15) detects a DTMF signal, when transmitting signal generated from the DTMF generator(15), to an office line.
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