SUBSCRIBER CIRCUIT

PROBLEM TO BE SOLVED: To provide a subscriber circuit capable of being made small in circuit scale, reduced in current consumption and small in size. SOLUTION: This subscriber circuit is provided with a power supply circuit 21 that receives a DC voltage from an AC/DC conversion adaptor 22 and a battery 23 connected in parallel, provides an output of the DC voltage from the battery 23 on the occurrence of a power failure and of the DC voltage from the AC/DC conversion adaptor 22 in the case of other than the power failure, a DC/DC converter 26 that receives an output voltage from the power supply circuit 21 and outputs a difference DC voltage selectively, a switch means 29 that feeds an output voltage of the DC/DC converter 26 to an analog telephone set, a hook state detection circuit 37 that detects a hook state of the analog telephone set, and a control means 28 that controls the DC/DC converter 26 and the switch means 29 based on an output of the hook state detection circuit 37 and an incoming call notice signal to apply a required voltage to the analog telephone set.