The object of the present invention is to remove the dead region of a diode bridge and maintain stable operations in a telephone terminal equipment interface circuit. In order to realize this object, a telephone terminal equipment interface circuit, according to the present invention comprises a diode bridge for rectifying line current supplied from a subscriber line and supplying the current to a call transmission/reception circuit, and a forward biasing circuit that supplies forward biased voltage to the diode bridge. Supplying forward biased current to the diode bridge makes the diode bridge operate in an activated state, thereby removing the dead region of the diode bridge and enabling more stable operations to be maintained in the interface circuit.