In one implementation, a computer-implemented method for graphical subselection is provided. To ensure the maintenance of an auxiliary unit of this type and to prolong its life using simple means, it is proposed, among other things, that the control unit will repeatedly signal actions to be taken to a driver of the vehicle or directly to the switch. The lever is movable between upper and lower positions, with its associated spring biasing the lever toward its upper position. Thus, network addresses for the client andor one or more of the intermediary devices can be inspected to facilitated a geographic location determination for the client based on the geographically significant portions.