Tap code: Difference between revisions

Revision as of 02:02, 22 February 2006

Revision as of 02:03, 22 February 2006

Line 1:

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 by in June [[1965]] by four POWs[[POW]]s 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".