| 摘要 |
PURPOSE:To realize LSI system in a subscriber circuit and highly compacted packing of the circuit for a communication device which supplies the call current to a terminal device, by selecting the DC voltage among plural types of DC voltages to supply the call current. CONSTITUTION:The power sources E1-E3 are provided to supply plural types of DC voltages to a subscriber circuit SLC. Then the selective connection is given between terminals F1 and F1', F2 and F2' or F3 and F3'. According to the region among the regions I-III that includes a telephone resistance RT, a line resistance Rl and a load resistance RL. In such way, the power consumption can be reduced for a call current supplying circuit BF'. |
