Knock code

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Tapcode for the Roman alphabet
1 2 3 4th 5
1 A. B. C / K D. E.
2 F. G H I. J
3 L. M. N O P
4th Q R. S. T U
5 V W. X Y Z
Knock Code Table

The knock Code ( English tap code is) a simple way, a text message Letter to code letter. The message is transmitted by a series of knockers ( English to tap ). It was often used by prison inmates to communicate across locked cells; they hit the metal bars of the prison doors, the water pipes or the walls between the cells.

design

The knock code is based on a Polybios square and uses a 5 × 5 grid of letters in which all letters of the Latin alphabet occur, except for the K, which is represented by a C.

The recipient only has to recognize the time interval between the individual knockers in order to identify individual letters.

Each letter is transmitted by tapping two numbers:

  • the first number determines the line (from top to bottom)
  • the second number determines the column (from left to right)

The pause between these two numbers is shorter than the pause between two consecutive letters.

For example, to code the letter "B", you type once, pause and then type twice. For the word "water" the coding looks like this:

W. A. S. S. E. R.
5, 2 1, 1 4, 3 4, 3 1, 5 4, 2
····· ·· · · ···· ··· ···· ··· · ····· ···· ··

The letter "X" is used to separate sentences and "K" stands for affirmations.

Because of the difficulty and length of time it takes to write a single letter, inmates often develop abbreviations and acronyms for common terms or phrases, such as “GN” for Good night or “GBU” for Good bless you .

In comparison, Morse Code is more difficult to send by tapping or hitting, as it either requires sounds of a defined length or two different-sounding sounds. It's also harder to learn. In order to be able to understand the knock code, one only has to memorize the Polybius square or master the alphabet and derive the square from it.

history

The origin of this coding goes back to the Polybios square of ancient Greece .

The knock code with the Cyrillic alphabet is said to have been used by prisoners of the Russian tsars and later in the Soviet Union by camp inmates in Siberia. The revolutionary and memoirist among the Decembrists Michail A. Bestuschew (1801–1871) is considered to be the developer of the alphabet made from knocking signs, with the help of which he is said to have exchanged messages in the Peters and Pauls fortress.

The knock code plays a role in Arthur Koestler's novel Sonnenfinsternis (Darkness at Noon, 1941). In the 1952 published novel Player Piano by Kurt Vonnegut a scene is also described, communicate the prisoner in this way. The code used in the novella is more primitive as it does not use the Polybios square, but simply represents each letter by the number of its position in the alphabet (for example, "P" is represented by 16 consecutive knockers).

The code was also used during the Vietnam War . In 1965, four prisoners of war held in the Hanoi Hilton Hỏa Lò prison introduced him ; one of them knew about it from the Second World War. The code was easy to learn, and newly arrived prisoners were able to use it fluently in a matter of days. It was even used when prisoners were seated next to each other but were not allowed to talk by patting each other on the thigh. By overcoming isolation with the knock code, the prisoners were allegedly able to maintain a chain of command and morale.

Web links

Individual evidence

  1. ↑ a b c 'Return with Honor': The Tap Code. (No longer available online.) In: American Experience . PBS archived from the original on November 10, 2012 ; Retrieved April 8, 2008 .
  2. ^ David Kahn : The Codebreakers - The Story of Secret Writing. 1996, ISBN 0-684-83130-9 .
  3. ^ Anne Krier: Travel as a Procedure: Subject Concepts and Epistemic Processes in the Russian Exile and Camp Literature of the 18th – 20th Centuries Century. University of Zurich: https://doi.org/10.5167/uzh-170586 Diss. P. 84
  4. ↑ Arthur Koestler: Darkness at Noon. (1941). Translated by Daphne Hardy. P. 19, Bantam Publishing paperback, 1981.
  5. ^ A b Jason Tudor: Vets, Flyers discuss ideology, time in POW camps. Air Force News Service, March 18, 1998, accessed April 8, 2008 .
  6. ↑ John McCain, Mark Salter: Faith of My Fathers . Random House, 1999, ISBN 0-375-50191-6 , pp. 211-212 (English).
  7. ^ A b Ernest C. Brace: A Code to Keep: The true story of America's longest held civilian prisoner of war in Vietnam . St. Martin's Press, 1988, ISBN 0-7090-3560-8 , pp. 171-172, 187-188 (English).