Tap Code The Tap Code is a code, commonly used by prisoners in jail to communicate with one another. The method of communicating is usually by "tapping" either the metal bars or the walls inside the cell, hence its name. It is a very simple code, not meant to avoid interception, since the messages are sent in cleartext. It was reportedly invented in June 1965 by four POWs imprisoned in Hoa Lo, Vietnam: Captain Carlyle ("Smitty") Harris, Lieutenant Phillip Butler, Lieutenant Robert Peel and Lieutenant Commander Robert Shumaker. Harris remembered an Air Force instructor who had shown him a code based on a five-by-five alphabet matrix (a Polybius square), as shown on the graph below. Each letter was communicated by tapping two numbers: the first designated the horizontal row and the second designated the vertical row. The letter "X" was used to break up sentences and the letter "C" replaced the letter "K". The Tap Code is outlined in the table below: | 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 | -+---+---+---+---+--- For example, to specify the letter "A", you would tap roughly the following: . . Or to communicate the word "WATER" the code would be the following (the time between each pair of numbers is smaller than the one between two different letters): ..... .. . . .... .... . ..... .... .. (5,2) (1,1) (4,4) (1,5) (4,2) W A T E R Because of the difficulty and length of time required for specifying a single letter, most prisoners devised abbreviations and acronyms for common items or phrases, such as "GN" for Good Night, or "GBU" for God Bless You. See also http://en.wikipedia.org/wiki/Knock_three_times_(disambiguation) References The Tap Code Online Tap Code Encoder/Decoder
its field expedient, these pilots made it up so anybody could use it/learn it without books, just something to tuckaway and carry with you in case they put the habeus-grabbous on you... Just remember its clear text , most folks have heard of it somewhat... p.o.w. in your own country , how whacked is that??
I agree that some would understand it, though keep in mind the uneducated masses possibly couldn't even spell Tap much less decipher your code. Haha. Another thing, if the foreigns are keeping us prisoner it will work the same way that it did for the POWs. How many can speak the English language now? It would work. Just hope it doesn't come to this. Remember, no surrender.
