| 摘要 |
<p>PURPOSE:To simplify the constitution of a subscriber circuit without using integrated circuit technique of a complex dielectric separating process, by realizing an integrated circuit for the subscriber circuit by the integrated circuit techinique of a P-N junction separating process. CONSTITUTION:An integrated circuit 15 for a subscriber circuit consists of a ringer sending circuit 13 and a DC current supply and 2-wire/4-wire converting circuit 14; a ringer signal is applied from ringer supply input terminals 16 and 17 to the circuit 15, and sent out to 2-wire terminals 11 and 12 according to a signal from a control terminal 31. Further, a direct current is flowd from the DC current supply circuit in the circuit 14 to the terminals 11 and 12 through the circuit 13, and the current is detected by the DC current monitoring circuit in the current 14. Audio signals are outputted from the terminals 11 and 12 to a 4- wire output terminal 18 through the circuits 13 and 14, and audio signals from the 4-wire input terminal 19 are applied to the terminals 11 and 12 reversely. In addition, a substrate voltage for P-N junction separation is supplied from the DC voltage supply circuit consisting of resistances 25 and 26, a capacitor 24, diodes 20 and 23, and a transistor 30, a transformer 22.</p> |
