PURPOSE: To prevent a call tone from being listened to, by stopping the operation of a converting section in a line corresponding setion after a line in call tone connecting state starts the transmission of a dial pulse, in a time division exchange.
CONSTITUTION: A line processor LPR stops the converting function of a series digital-analog converting section DA until a prescribed time is elapsed after a series of dial pulses are finished for transmission just after the start of the dial pulses and the transmission of the call tone to a telephone set TEL is blocked, in transmitting the dial pulses from the telephone set TEL in the call tone connecting state. Then, the call tone is prevented from being listened again to the telephone set completing the transmission of the dial pulses.
HAYASHI KIYOBUMI
TAKATOU KENJI
HIYOUDOU WATARU
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