The invention relates to a method for the data transmission from an emitter to a receiver in an AC voltage network, comprising a distributor and at least one user group with one or several users, wherein the emitter feeds a signal to the AC voltage network by means of a power source. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a transmission line for detection by an etalon fringe detector. The vehicles further include a control module configured to control operation of the fan based on one or more inputs related to operation of the alternator. First and second contact plugs are formed over the first and second diffusion regions, respectively. The brush roll is configured for rotation along an axis positioned to have a selected spatial relationship relative to an exit window in the housing.