Keyboard .

Keyboard is input device . Programs and data are entered into a computer through a keyboard which is attached to a computer . A keyboard is similar to the keyboard of a typewriter. It contains letters,digits,special characters,function keys. When  a key is pressed, an electronic signal is produced, which is detected by an electronic circuit called keyboard encoder .

A computer include all the keys found on a typewriter plus some additional keys . These additional keys are cursor control (i.e., moving the cursor around on the screen), insert, delete, and scroll control keys. There are a total of 101 keys (some have more). At the right side of the keyboard is the numeric keypad with numbers and basic mathematical symbols.

The numeric keypad can also be used for cursor control. This double function of numeric keypad is controlled by the Num lock key .

The keyboard contains a small built in processor . When you press a key , this processor detects it and sends a number (binary number) corresponding to that key  to the keyboard controller , located on the motherboard . This code is transmitted to the processor (CPU) . The CPU then processes it using a program called keyboard drive . The keyboard drive translates the codes into their corresponding characters .