| 摘要 |
PROBLEM TO BE SOLVED: To perform normal power supply and reversed power supply to a subscriber line with an economical configuration and with power consumption reduced. SOLUTION: This circuit consists of a reversing switch 2 and a common power supply 3, and the economically configured common power supply 3 performs normal power supply and reversed power supply to the subscriber terminal 1 through the switch formed by connecting a field-effect transistor for normal power supply that is turned on only in a normal power supply mode and a field-effect transistor for reversed power supply that is turned on only in a reversed power supply mode as a reversed polarity state to each other and also as a confounded state. |
