A remote control unit carries control keys and possesses in its back face a battery housing with central and peripheral power supply contacts, and also with signal transmission contacts. An active support carries a portion in relief suitable for penetrating into the housing of the unit to take the place of the power supply battery. Two power supply terminals are connected to a power supply line and arranged so as to bear against the respective power supply contacts of the unit when the portion in relief is inserted and locked in the housing of the unit, with the same applying for signal transmission terminals that are arranged on the portion in relief in positions that correspond to the transmission contacts of the unit.