It is a text base input device that allows the user to input alphabets, numbers and other characters. It consists of a set of keys mounted on a board.

The different keys are as follows:

1. Alphanumeric Keypad:

It consists of keys for the English alphabets, 0 to 9 numbers, and special characters like + “ / * ( ), etc.

2. Function Keys:

There are twelve function keys labeled F1, F2, F3… F12. The functions assigned to these keys differ from one software package to another. These keys are also user-programmable keys

3. Special-function Keys:

These keys have special functions assigned to them and can be used only for those specific purposes. The functions of some of the important keys are defined below.

(i) Enter:

It is similar to the ‘return’ key of the typewriter and is used to execute a command or program.

(ii) Spacebar:

It is used to enter a space at the current cursor location.

(iii) Backspace:

This key is used to move the cursor one position to the left and also delete the character in that position.

(iv) Delete:

It is used to delete the character at the cursor position.

(v) Insert:

Insert key is used to toggle between insert and overwrite mode during data entry.

(vi) Shift:

This key is used to type capital letters when pressed along with an alphabet key. Also used to type the special characters located on the upper side of a key that has two characters defined on the same key.

(vii) Caps Lock:

Caps Lock is used to toggle between the capital lock features. When ‘on’, it locks the alphanumeric keypad for capital letters input only.

(viii) Tab: 

Tab is used to move the cursor to the next tab position defined in the document. Also, it is used to insert indentation into a document.

(ix) Ctrl: 

The control key is used in conjunction with other keys to provide additional functionality on the keyboard.

(x) Alt:

Also, like the control key, the Alt key is always used in combination with other keys to perform specific tasks. 

(xi) Esc:

This key is usually used to negate a command. Also used to cancel or abort executing programs.

4. Numeric Keypad:

Numeric keypad is located on.the right side of the keyboard and consists of keys having numbers (0 to 9) and mathematical operators (+ “ * /) defined on them. This keypad is provided to support quick entry for numerical data.

5. Cursor Movement Keys: 

These are arrow keys and are used to move the cursor in the direction as indicated by the arrow (up, down, left, right).