What is Keyboard and How it Works


The commonly used input device is a keyboard. It is the most important device for communicating between the operator and the computer. This is connected to the CPU. The keyboard is used to input data and instructions into the computer. A computer keyboard is very much like a standard type writer keyboard with few additional keys. It consists of the standard typewriter keys as well as a numeric keypad and It contains alphabets, digits, special characters and some control keys.

Keyboards are available in three types:
(i) Standard Keyboard with 83/84 keys.
(ii) Enhanced Keyboard with 101 / 102 keys.
(iii) Windows Keyboard with 104 keys.

Described below are the keyboard keys along with their different functions

 Typewriter keys :These are normal keys on the key board. These include letters, numbers and punctuation symbols.

Function keys :These are the keys labeled F1 to F12. These carry our different functions. These are identified as FI through F2 on the top most row of the keyboard. These keys are programmed to perform special functions.

Cursor keys :These keys are marked and are called the left, right, up and down arrow keys(←, →, ↑, ↓). The keys are used to move the cursor left, right, down or up around the screen. These are present on the right hand side of the key board.

Numeric Key Pad :It allows numeric digits to be entered. These keys which are arranged like a calculator, have two different functions according to the status of the Num Lock key. While the num lock is not locked, these keys are used.

Caps lock key :It allows to enter capital letters. If we press caps lock once, any letter you type will appear in upper case. When pressed once, the caps lock light comes on, and any character you type appears as a capital letter. When this key is pressed again, the character you type appears in a lower case.

Shift key :It allows the capital alphabetical characters, on certain keys to be appeared. when an alphabet is typed, it is shown in the lower case, Holding down Shift key and then pressing an alphabet key causes it will appear in upper case.
Example: when you press Shift-d, you get a capital D. However, if the Caps lock is ON than this effect is reversed.

Ctrl and Alt keys :
These keys are often used in combination with other keys, to produce special actions.
Example: when you pressing Ctrl and C simultaneously, aborts the current task or command being executed and returns you to DOS prompt. If you are  pressing Ctrl, Alt and Del keys simultaneously, the machine is automatically restarted.

Enter key :
The Enter key is used for two main purposes. It represents the end of the current line, and takes you back to the first column of the next line. It is also used to represent the end of the command data. Enter key is also referred to as Return key.

Pause :
Pressing the pause key instructs Dos to stop the scrolling of information on the screen. When pressed enters the computer in pause mode. You can use this key to read the contents of a large file.

Tab Key :It is used to move the cursor position faster than the space bar key. It is also used  for  moving  from one option to another option in a menu. When pressed together with the Shift key, the cursor is moved to the next tab stop on the left. Default tab stops are at every eight columns.

Esc Key : (Escape Key)You can use this key to cancel or ignore the entry or command you have just entered. In many programs, the Esc key returns you to the previous menu screen or exit from the program.

Prtscr : (Print Screen key)
It this key is pressed then whatever is being displayed in the screen gets printed on the printer. Prints out all information currently appearing on the screen to the printer, when pressed together with the Shift key.

Del Key : (Delete  key )
Erases the character that the cursor is currently on. If this key is pressed, then it deletes
a character at the current cursor position on the screen.

Backspace Key :This key erases the character to the left, moving the cursor back one character at a line, erasing what you typed. When pressed once, erases any character to the left of the cursor.

Spacebar  : Spacebar is the longest key in the last row of the keyboard. Presenting spacebar shifts the cursor one position to the right

Alphanumeric keys: These keys have functions identical to those of an ordinary typewriter & are used for entering alphanumeric information, it is a combination of the words, alphabet and numeric.

Home key : Shifts the cursor to the top of the document or the beginning of the line.

End key : Shifts the cursor to the end of the document or the end of the line.

Pgup (page - up) key : Moves the cursor to the previous or page of the document.

Pgdn (page-down key ) : Moves the cursor to the next screen or page.

Ins (Insert key) : It allows insertion of characters to the left of the cursor. This is a toggle key. Pressing once brings the insert mode "ON" and pressing again will toggle position on the screen.

Special keys : These keys may have different functions depending on the software that is being used.

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