Some variation in electrical interfaces and connectors exist, but they are rare.
For the most part, keyboards can be "hot plugged" without damaging either the keyboard or the computer.
Keyboards come in a wide variety of keyboard layouts including non-English language keyboards. The initial common layout was "88" keys used with the IBM PC and XT. The AT introduced a 102 key keyboard that added two additional function keys (to the 10 already present); and word processing keys separate from the keypad. In 1995 a couple of Windows 95 specific keys were added to the keyboard. The Windows keys generally generate codes like Ctrl-Esc that have special meaning to Windows. Most keyboards use the QWERTY layout with few variations in the positions of most non-typewriter keys. The position of a few keys -- Alt, Ctrl, |, Esc changes from keyboard to keyboard.
Keyboard characters are read out at something like 500 to 1000 characters per second -- which is much faster than anyone can type.
Return To Index Copyright 1994-2008 by Donald Kenney.