Tap code: Difference between revisions

Revision as of 15:42, 8 February 2006

Revision as of 02:00, 22 February 2006

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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]].

{{context}}

It was reportedly invented by 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]], 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:

Line 15 ⟶ 18:

-+---+---+---+---+---

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

Line 27 ⟶ 28:

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''.

==References==

*[http://www.airsoftgent.be/dbase/tapcode.htm The Tap Code]