Editing Scancode (section)

== Variants ==

Mapping key positions by row and column requires less complex [[computer hardware]]; therefore, in the past, using [[software]] or [[firmware]] to translate the scancodes to text characters was less expensive than wiring the keyboard by text character.<ref>For example, the traditional 12-key numeric keypad is scanned as 3 columns by 4 rows, requiring a total of 7 connections. Scanning each key separately would require 12 connections.</ref>  This cost difference is not as profound as it used to be.  However, many types of computers still use their traditional scancodes to maintain [[backward compatibility]].

Some keyboard standards include a scancode for each key being pressed and a different one for each key being released.  In addition, many keyboard standards (for example, [[IBM PC compatible]] standards) allow the keyboard itself to generate "[[typematic]]" repeating keys by having the keyboard itself generate the pressed-key scancode repeatedly while the key is held down, with the release scancode sent once when the key is released.