The present invention provides a flat panel display device, which includes a backlight system and a display panel. Thereby the modulated carrier wave carries information not only by the digitally encoded data words but also by the different modulation indices used for successive intervals that thus also represent information symbols. The second protrusions are connected to the side wall of the recess on the card center side. The switch stores at least one PSTN destination address and at least one IP network destination address for each subscriber.