A loudspeaker includes a frame, a diaphragm and an electric driving arrangement for moving the diaphragm along an axis with respect to the frame. The third functional element conveys, during operation, light coupled thereinto, and has at least one essentially planar boundary surface, which deflects light conveyed in the apparatus. The second blocks are mapped into physical-layer frames, including repetitive copies of the second blocks if space permits. The second request includes a protocol header that specifies a base uniform resource locator.