The invention relates to a process for the preparation of onium salts with dialkylphosphate, dialkylphosphinate or alkyl- or alkylphosphonate anions by reaction of an onium halide with a triallyl phosphate, alkyl dialkylphosphinate, dialkyl alkylphosphonate or trialkylsilyl ester or mixed alkyl trialkylsilyl ester of phosphoric, dialkylphosphinic or alkylphosphonic acid. The interface circuit may be made up of an integrated circuit package that provides a first region and a second region. In one embodiment, the back surface of the panels can be ventilated in order to increase the efficiency of the solar collection system and the ventilation of possible voids in the building.