Keypad
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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 decimal point and other more advanced functions.
Keypads are a part of mobile phones that are replaceable and sit on a sensor board. Some multimedia mobile phones have a small joystick which has a cap to match the keypad.
Keypads are also a feature of some combination locks. This type of lock is often used on doors, such as that found at the main entrance to some offices.
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