| 摘要 |
PURPOSE:To recognize a transmission time of a DTMF signal at a slave set side by allowing a master station to send the DTMF signal to a telephone line so long as the key operation of the slave set continues. CONSTITUTION:When a ten-key of a key input section of a slave set is operated, a control circuit 9' gives a data representing the operated ten-key to a MODEM 8' repetitively for, e.g. thrice. While the data is fed to the MODEM 8' repetitively for thrice or before the 3rd data supply is finished, whether or not the ten-key is in the operating state is discriminated. When the nonoperation of the ten-key is discriminated as a result of discrimination, as soon as the transmission of the 3rd data is finished, the circuit 9' operates a timer or a counter to stop the data supply till the timer time(t) reaches the time T or the count of the counter reaches the count corresponding to the time T. On the other hand, as the result of discrimination, when the operation of the ten-key is discriminated, the circuit 9' keeps sending a specific data till the release of the key operation is discriminated.
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