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:
“Anna who was mad,
I have a knife in my armpit.
When I stand on tiptoe I tap out messages.”
—Anne Sexton (1928–1974)
“...I had grown up in a world that was dominated by immature age. Not by vigorous immaturity, but by immaturity that was old and tired and prudent, that loved ritual and rubric, and was utterly wanting in curiosity about the new and the strange. Its era has passed away, and the world it made has crumbled around us. Its finest creation, a code of manners, has been ridiculed and discarded.”
—Ellen Glasgow (1873–1945)