In computing, a keyboard is a peripheral partially modeled after the typewriter keyboard.
Physically, a keyboard is an arrangement of rectangular buttons, or keys. A keyboard typically has
characters engraved or printed on the keys; in most cases, each press of a key corresponds to a
single written symbol. However, to produce some symbols requires pressing and holding several keys
simultaneously or in sequence; other keys do not produce any symbol, but instead affect the
operation of the computer or the keyboard itself. See input method editor.
A majority of all keyboard keys produce letters, numbers or signs (characters) that are appropriate
for the operator's language. Other keys can produce actions when pressed, and other actions are
available by the simultaneous pressing of more than one action key.
A keypad is a set of buttons arranged in a block which usually bear digits and other symbols
but not a complete set of alphabetical letters. If it mostly contains numbers then it can also be
called a numeric keypad. Keypads are found on many alphanumeric keyboards and on other
devices such as calculators, combination locks and telephones which require largely numeric input.
A computer keyboard usually contains a small numeric keypad with a calculator-style arrangement
of buttons duplicating the numeric and arithmetic keys on the main keyboard to allow efficient
entry of numerical data. This number pad (commonly abbreviated to "numpad") is usually positioned
on the right side of the keyboard because most people are right handed.
Many laptop computers have special function
keys which turn part of the alphabetical keyboard into a numerical keypad as there is insufficient
space to allow a separate keypad to be built into the laptop's chassis. Separate plug-in keypads
can be purchased.
By convention, the keys on calculator-style keypads are arranged such that 123 is on the bottom row.
In contrast, a telephone keypad has the 123 keys at the top. It also has buttons labelled * (star)
and # (number sign, "pound" or "hash") either side of the zero. Most of the keys also bear letters
which have had several auxiliary uses, such as remembering area codes or whole telephone numbers.
The keypad of a calculator contains the digits 0 through 9, together with the four arithmetic
operations, the point and other more advanced functions.
Keypads are also a feature of some combination locks. This type of lock is often used on doors,
such as thatfound at the main entrance to some offices.
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