| 摘要 |
PURPOSE:To transmit earth information to an exchange when the power supply of a channel converter is interrupted by providing a bias voltage providing means in a signal output circuit transmitting a dial signal received by the channel translating equipment (CHTR) to the exchange. CONSTITUTION:The bias voltage providing means using resistors R1-R4 is provided in the signal output circuit transmitting the dial signal to the exchange side by performing on/off control of transistors (Trs) Tr1, Tr2 with the dial signal transmitted from a driver S, and the earth information is transmitted to the exchange side by turning on a Tr3 when a power supply -21V of the channel converter is normal so as to allow he driver S to perform on/off control of the Tr1, Tr2 and by using resistors R2, R3 so as to turn on/off the Tr1, Tr2 when the power supply -21V is interrupted. Since the earth information is transmitted when a power supply of the channel translating equipment or the like of the FDM system is failed, a charging error is improved. |
