There is some variation between different keyboard models in the physical layout-i.e., how many keys there are and how they are positioned on the keyboard. Key types A typical 105-key computer keyboard, consisting of sections with different types of keysĪ computer keyboard consists of alphanumeric or character keys for typing, modifier keys for altering the functions of other keys, navigation keys for moving the text cursor on the screen, function keys and system command keys-such as Esc and Break-for special actions, and often a numeric keypad to facilitate calculations. Modern USB keyboards are plug-and-play they communicate their (default) visual layout to the OS when connected (though the user is still able to reset this at will). Some settings enable the user to type supplementary symbols that are not engraved on the keys used to invoke them.

Thus the symbol shown on the physical key-top need not be the same as appears on the screen or goes into a document being typed. In addition, software may be available to modify or extend keyboard functionality. Often, a user can change keyboard mapping in system settings. This means that a physical keyboard may be dynamically mapped to any layout without switching hardware components-merely by changing the software that interprets the keystrokes. The OS converts the scancode into a specific binary character code using a 'scancode to character' conversion table, called the keyboard mapping table. Modern computer keyboards are designed to send a scancode to the operating system (OS) when a key is pressed or released: this code reports only the key's row and column, not the specific character engraved on that key. Functional layout is the arrangement of the key-meaning association or keyboard mapping, determined in software, of all the keys of a keyboard it is this (rather than the legends) that determines the actual response to a key press. Visual layout is the arrangement of the legends (labels, markings, engravings) that appear on those keys. Physical layout is the actual positioning of keys on a keyboard. The 104-key US QWERTY layoutĪ keyboard layout is any specific physical, visual, or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer keyboard, mobile phone, or other computer-controlled typographic keyboard. For keyboards used in music, see Musical keyboard. For the underlying physical structure and electronic mechanisms of computer keyboards, see Keyboard technology. This article is about the physical and visual arrangement of the keys of a computer keyboard and their function as defined by software.

Standard keypad layout