The tap code, sometimes called the knock code, is a way to encode messages, letter by letter, in a very simple way and transmit it using a series of tap sounds, hence its name. It has been commonly used by prisoners to communicate with each other. The method of communicating is usually by "tapping" either the metal bars, pipes or the walls inside the cell.
Famous quotes containing the words tap and/or code:
“A book is like a man—clever and dull, brave and cowardly, beautiful and ugly. For every flowering thought there will be a page like a wet and mangy mongrel, and for every looping flight a tap on the wing and a reminder that wax cannot hold the feathers firm too near the sun.”
—John Steinbeck (1902–1968)
“... the self respect of individuals ought to make them demand of their leaders conformity with an agreed-upon code of ethics and moral conduct.”
—Mary Barnett Gilson (1877–?)