A dimmer comprising a controller and a wireless adapter coupled to the controller. The dimmer is connected to a LED lamp through a switched AC line. The controller is configured to send to the lamp user control information, and provisioning information for allowing the lamp to distinguish the control information transmitted by the dimmer from control information transmitted by other dimmers in the vicinity of the lamp. For performing the provisioning, the controller is configured, after turning-ON the lamp, to wirelessly transmit thereto, at a provisioning frequency F0, provisioning information comprising an identification of an RF frequency Fn that is preselected as the dimmer-specific frequency for controlling the lamp, and to vary the wireless transmit frequency from F0 to Fn for henceforth sending thereat the control information to the lamp.