| 摘要 |
PURPOSE:To obtain an inexpensive and small-sized signal converter for exchange with a simple constitution by removing a capacitor of a series connection circuit comprising a call signal detecting circuit, a capacitor and a resistor, and connecting the both terminals of an off-hook detecting circuit of an incoming subscriber to the position at which above devices are removed. CONSTITUTION:In the series circuit comprising the capacitor and the resistor including the call signal detecting circuit RGD, the capacitor is removed and both ends of the off-hook detecting circuit LP of incoming subscriber are connected to the capacitor removed position. Through the constitution above, when both contacts an are hooked on, the circuit viewed from a subscriber exchange is a circuit having a path of call signal detecting circuit RGD-DC cut-off capacitor C2 transformer so as to form a pseudo telephone circuit. When a ringing signal is transmitted from the subscriber exchange side, it is detected by the RGD, which transfers a digital signal to a subscriber signal converter (not shown) so as to attain calling. When the subscriber responds, a loop circuit LP detects it, the contacts an are changed over and talking is conducted via the loop circuit LP being a low resistance. |
