Keyboard by Jeff Tyson
The keyboard is the main input peripheral used by all computers. The keyboard allows for
user input and action with the computer. Much like many type writers the keyboard has all
the letters of the alphabet, numbers 0 - 9 and additional special operational keys.
Types of Keyboards
Keyboards have changed very little in layout since their introduction. In fact, the most
common change has simply been the natural evolution of adding more keys that provide
The most common keyboards are:
101-key Enhanced keyboard
104-key Windows keyboard
82-key Apple standard keyboard
108-key Apple Extended keyboard
Portable computers such as laptops quite often have custom keyboards that have slightly
different key arrangements than a standard keyboard. Also, many system manufacturers add
specialty buttons to the standard layout.
A typical keyboard has four basic types of keys:
The typing keys are the section of the keyboard that contain the letter keys, generally
laid out in the same style that was common for typewriters. This layout, known as QWERTY
for the first six letters in the layout, was originally designed to slow down fast typists
by making the arrangement of the keys somewhat awkward! The reason that typewriter
manufacturers did this was because the mechanical arms that imprinted each character on the
paper could jam together if the keys were pressed too rapidly. Because it has been long
established as a standard, and people have become accustomed to the QWERTY configuration,
manufacturers developed keyboards for computers using the same layout, even though jamming
is no longer an issue. Critics of the QWERTY layout have adopted another layout, Dvorak,
that places the most commonly used letters in the most convenient arrangement.
An Apple Extended keyboard.
The numeric keypad is a part of the natural evolution mentioned previously. As the use of
computers in business environments increased, so did the need for speedy data entry. Since
a large part of the data was numbers, a set of 17 keys was added to the keyboard. These
keys are laid out in the same configuration used by most adding machines and calculators,
to facilitate the transition to computer for clerks accustomed to these other machines.
In 1986, IBM extended the basic keyboard with the addition of function and control keys.
The function keys, arranged in a line across the top of the keyboard, could be assigned
specific commands by the current application or the operating system. Control keys provided
cursor and screen control. Four keys arranged in an inverted T formation between the typing
keys and numeric keypad allow the user to move the cursor on the display in small
increments. The control keys allow the user to make large jumps in most applications.
Common control keys include:
- Page Up
- Page Down
- Control (Ctrl)
- Alternate (Alt)
- Escape (Esc)
The Windows keyboard adds some extra control keys: two Windows or Start keys, and an
Application key. The Apple keyboards are specific to Apple Mac systems.
The most common keyboard connectors are:
- 5-pin DIN (Deustche Industrie Norm) connector
- 6-pin IBM PS/2 mini-DIN connector
- 4-pin USB (Universal Serial Bus) connector
- internal connector (for laptops)