| 摘要 |
PURPOSE:To transmit 50Hz charging information to a subscriber's call meter by separat ing a circuit inducing a 50Hz signal to the subscriber's call meter from a talking current supply circuit formed as an electronic circuit and constituting the inducing circuit with electromagnetic components so as to prevent an in-phase mode voltage in 50Hz from changing into a differential mode voltage. CONSTITUTION:A subscriber circuit consists of a 50Hz inducing part 1 comprising electromagnetic components transmitting a 50Hz charging signal to a subscriber's call meter and a subscriber circuit section 2 comprising mainly electronic components. A talking current supply section 3 of the circuit part 2 detects a call at a subscriber terminal and the current supply part 3 detects a dial number of the destination from an exchange control part. Then a channel is set under the control of the exchange control part to activate a relay A2 of the circuit section 2 and the talking current to the subscriber terminal device is supplied through a relay A1 of the inducing part 1. Then the relay A2 of the circuit part 2 is activated for a prescribed time at the response of the called party to activate the relay M1 of the inducing part 1 sequentially, and the 50Hz charging signal is transmitted to the subscriber's call meter as an in-phase voltage from an oscillator OSC via a transformer LO.
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