A high speed transimpedance amplifier includes an inverting unit, at least one gain module, and a feedback resistor. A local gateway is coupled to the femto cellular access network for receiving data packets transmitted on the femto cellular access network and for routing the data packets to one of a local IP network and an external IP network, based on a destination address associated with the data packets. By extending the stiffening regions diagonally from the center of the club face to the four quadrants, a more uniform stress distribution can be obtained and therefore more uniform performance. Further, through the patterning, it is possible to implement a color display device which does not exhibit performance degradation. The electrical current to an infusion pump is measured. The signal controller includes a bias supply unit, which applies a predetermined bias voltage to the fixed electrodes during a test mode.