Patent ID: 7742040

Claim:
A keypad comprising: a plurality of keys, wherein each key in the plurality of keys is coupled to a first switch, the first switch being coupled to a common electrical interconnection, and a second switch, the second switch being coupled to a matrix electrical interconnection, wherein the matrix electrical interconnection includes one or more row lines and one or more column lines; and a controller configured to detect a signal on the common electrical interconnection and configured to provide a scan signal to the matrix electrical interconnection, wherein, responsive to detecting a change of state in the signal on the common electrical interconnection indicating that a first key in the plurality of keys has been depressed, the controller is further configured to: direct the scan signal to a corresponding column line in the one or more column lines, direct dummy signals to at least one row line, and read the one or more row lines associated with the corresponding column line to detect the first key in the plurality of keys.