Abstract: The invention relates to a hydraulic steering system architecture comprising at least one steering control actuator having chambers connected to the outlets of a directional-control valve, an accumulator, and an electrically-driven pump unit associated with an emergency supply. The hydraulic system also comprises a general selector arranged, in a normal mode of operation, to connect the feed port of the directional-control valve to a pressure-generator device and the return port of the directional-control valve to a main supply associated with the pressure-generator device, while also ensuring that the emergency supply is filled, and in an alternate mode of operation, to connect the feed port of the directional-control valve to the accumulator.