The invention relates to a domestic surface treatment appliance, such as a vacuum cleaner, iron or lawn mower, provided with a treatment head for treating a surface by wiping along or passing over said surface. A sender and a receiver share a seed key in advance, and then transmit and receive random numbers superimposed on carrier light accompanied with fluctuations, where transmission basis is determined by a random number. Each of the signal coupling portions couples an alternating current control signal to the refrigerant pipes and exhibits a predetermined impedance with respect to an AC electric signal. The control gate is formed with a planarized upper surface. Preferably, the drug substance is beclomethasone dipropionate. The examples relate to the addition or omission of subordinate switching pulses during long or short frame-switching pulses and to an active control of the number of subordinate switching pulses, depending on the loading of the switches.