Tap Code

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.

Read more about Tap Code:  Design, History

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)

    Many people will say to working mothers, in effect, “I don’t think you can have it all.” The phrase for “have it all” is code for “have your cake and eat it too.” What these people really mean is that achievement in the workplace has always come at a price—usually a significant personal price; conversely, women who stayed home with their children were seen as having sacrificed a great deal of their own ambition for their families.
    Anne C. Weisberg (20th century)