A keyboard layout is any specific mechanical, visual, or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer, typewriter, or other typographic keyboard. Mechanical layout The placements and keys of a keyboard. Visual layout The arrangement of the legends (labels, markings, engravings) that appear on the keys of a keyboard. Functional layout The arrangement of the key-meaning associations, determined in software, of all the keys of a keyboard. Most computer keyboards are designed to send scancodes to the operating system, rather than directly sending characters. From there, the series of scancodes is converted into a character stream by keyboard layout software. This allows a physical keyboard to be dynamically mapped to any number of layouts without switching hardware components – merely by changing the software that interprets the keystrokes. It is usually possible for an advanced user to change keyboard operation, and third-party software is available to modify or extend keyboard functionality.