An electrical device includes an electronic control unit including a radio communication interface provided with a planar internal radio antenna housed inside a first housing of the electrical device and including a first radiating element. The electrical device furthermore includes a movable coupling element connected to an external radio antenna, the coupling element being provided with a second radiating element and being able to be moved between a position connected to the housing of the electrical device and a position disconnected from the housing. In the connected position, the coupling element is positioned facing the internal radio antenna while being separated therefrom by an electrically insulating element, the second radiating element being coupled to the first radiating element so as to receive electromagnetic radiation emitted by the first radiating element.