Input and Output Devices of Computer

A desktop computer is made up of three parts as discussed in computer components. Apart from CPU(central processing unit), the other two main components are input and output devices. These devices communicate with CPU to receive the inputs from a user and output the results in some form or the other.

Input Devices

The devices which we use to give the command to a computer to perform certain functions are called input devices of a computer.

Keyboard

The most common input device of a computer is a keyboard which is used to give instructions to the CPU.

Keyboard Interface types

• 5-pin DIN( Dutch Industry Norms)  socket interface.
• PS/2 connector
• USB interface
• Wireless interface

How DIN socket on the motherboard interacts with Keyboard

Other Features of Keyboard

• Older Keyboards had 87 Keys. Numeric Keypad was not there.
• Newer Keyboards have 101 or 105 Keys. Function Keys F1 to F12 are also there.
• F1 to F10 are used as pre-defined shortcut Keys for various programs.
• F11 to F12 are empty keys and can be programmed by the user.
• Keyboards also have their own microcontrollers. Most common of these microcontrollers are 8048(in older Keyboards), 8049(PROM), 8748/8749 ( EPROM).
• Keyboards come in two types: (a)Membrane Keyboards=> They have pressure sensitive Flexible PCB. They are non-repairable.(b) Cherry Keyboard=>These type of boards have mechanical Keys and are repairable.
• Cherry type keyboards are expensive than membrane-type but have a longer life and more reliable .
• Connectivity Type: DIN type , PS/2 , USB .

 Mouse.

It is also an input device used for pointing and selecting. It enhances the graphical user interface capabilities of operating systems by acting as a dedicated pointing device. The mouse comes in mechanical and optical forms.The interfaces are serial , PS/2 , USB and cordless.

Output Devices:

The devices which provide the output in form of audio , video or text form are called out devices of a computer.

Examples of computer output devices

• Printers
• Monitors or LCD/LED
• Speakers or Headphone