If I am looking at this correctly, the one drawback to this design is that you can't detect multiple keypresses in the sam row, right? In fact, holding two keys down in the same row could cause the wrong character code to be generated. Like holding down 1,1,and 1,8 gives you the code for 1,9, right? Not trying to nitpick. Just wanted to make sure I understood the advantages and disadvantages to the design.