A first current is driven through a first current path from a first common node, through a key matrix, and to a second common node when a key is pressed. A first measurement of the first current path resistance is made. A second current is then driven through a second current path from the second common node, through the key matrix, and to the first common node. A second measurement of the second current path resistance is made. The first and second measurements are used to identify the key that was pressed. Each key corresponds to a unique pair of first and second measurement values. In one example, non-linear resistance circuits are disposed at the ends of the row and column conductors of the key matrix such that a row resistor in the first current path is measured independently of a column resistor in the second current path.