How the tap code worksby Mark Steil, Minnesota Public Radio
St. Paul, Minn. — Here's how the tap code works. It's based on a 25 letter alphabet, so throw out 'k' and use 'c' for that letter in a word. The remaining 25 letters are arranged in five rows:
a b c d e
f g h i j
l m n o p
q r s t u
v w x y z
The first series of taps signals the row, the second series of taps the position of the letter in that row. So for 'L' Thorsness taps three times (third row), then after a short pause he taps once (first letter in that row). For 'T' he taps four and four (fourth row, fourth letter).