Method of operating a power supply and communication entity intended to form part of a system with at least one home-automation actuator comprising an electric motor for driving a movable element in a building, the power supply and communication entity comprising two electrical terminals for linking to the actuator, making it possible to power the actuator and allowing communication between the actuator and the power supply and communication entity, the method comprising two mutually exclusive modes of operation, a command execution mode and a communication mode, to each mode of operation there corresponding a specific power supply signal, the method comprising the steps: —choice of a mode of operation; —generation between the terminals of a power supply signal specific to the mode of operation chosen.