Tap code

The Tap Code:

         | 1 | 2 | 3 | 4 | 5 |   
        -+---+---+---+---+---+   
        1| A | B | C | D | E |   
        -+---+---+---+---+---+   
        2| F | G | H | I | J |  
        -+---+---+---+---+---+
        3| L | M | N | O | P |
        -+---+---+---+---+---+
        4| Q | R | S | T | U |
        -+---+---+---+---+---+
        5| V | W | X | Y | Z |
        -+---+---+---+---+---+

---

To use the code, a prisoner would first indicate which row 1-5 and then after a pause- but not long enough to denote a different letter- would follow up with the column to specify which letter.

For example, the letter "A" would roughly be: . . . . = (Row, Column)

Or to communicate the word "WATER" the code would be

..... ..  . .  .... ....  . ..... .... ..

(5,2)    (1,1)   (4,4)      (1,5)   (4, 2)

W        A       T          E        R