A method and a central subscriber database are provided for performing a permission status check in a mobile network. The body voltage of the device is initialized to the low end of range at time zero, and then a transient, two dimensional sweep of gate and drain voltages is performed. The switch circuit is formed of plural diode-coupled MOS transistors, so that a trigger voltage of the SCR is determined by threshold voltages of the MOS transistors. A multi-layered cap is present on the upper surface of the gate conductor.