A subscriber line interface circuit (1') for supplying line current (IL') to a two-wire transmission line connected to a load (RL'), comprises a single current amplifier (3'). That single current amplifier (3') is to be connected with its output terminal to one (B') of the wires (A', B') of the transmission line, while the other wire (A') of the transmission line is to be connected to a voltage source (V1') that can be provided within the subscriber line interface circuit (1') or external thereto.