| 摘要 |
PURPOSE:To heighten the measuring accuracy of a call time and to sufficiently perform additional charging, by measuring a time interval between a first pulse and second pulse of the periodical collection signal of a charging pulse, and shortening the call time to the one calculated by the above measurement. CONSTITUTION:Only three pulses, a response collection signal A generated first by the response of an opponent, the periodical collection signals B1 and B2 out of the charging pulses sent from a central telephone exchange, etc., are detected, and a cycle T between the signals B1 and B2 is measured, and alpha T can be calculated by multiplying a prescribed compaction ratio (alpha) by the cycle. Also, an actual coin collection signal (p) in the inside of a telephone set generates the pulses of two frequencies of alpha1 and alpha2 when detecting the signal A, and generates synchronized b1 and b2 for the B1 and the B2, and the periodical collection signals behind a B3 are neglected, and c1, c2,... are generated by the cycle alpha T calculated previously, thereby, the additional charging is performed. Thus, since time measurement is performed between the signals B1 and B2 whose pulse waveforms are equal, the measuring accuracy can be improved, and appropriate additional charging can be performed. Also, since the collection of two frequencies can be performed at a single action, it is possible to uniformize an addition ratio.
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