| 摘要 |
PURPOSE:To eliminate the distortion of a dial pulse by disconnecting a capacitor circuit during dial transmission in a dial transmission circuit using an electronic choke. CONSTITUTION:A control section 4' turns off a photocoupler P3 during dialing and disconnects a capacitor C from a B line 6, then a photocoupler P1 is turned off and a photocoupler P2 is turned on to bring a base voltage of a transistor Q2 to a high level. Since no effect of the capacitor C is given, the base voltage does momentarily to the high level, a Darlington circuit DC is turned on, a make-side current waveform of a dial pulse is a rectangular wave and no distortion is given, then the reception side is connected correctly without mis- connection.
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