WAN stands for Wide Area Network. WAN is a type of computer network that covers a large area. The computers (or terminals) connected to this type of network can be in different cities or countries. Computers in a WAN are often connected through telephone lines. However, they can also be connected through leased lines, microwave or satellite systems.

Typically, a WAN consists of two or more LANs connected together across a wide geographical area. The Internet is the world's largest WAN. It connects many computers and LANs around the world and making it as web.

In WAN, usually the personal computers are used as terminals to access the larger computer such as mainframe or minicomputer. Special software is used on each personal computer (connected to WAN) to work it as terminal. This software is known as terminal emulation software.

The larger computer to which the terminal (or PC) is attached is called host computer. The terminal can upload or download data files to and from the host computer. File transfer software is used in the terminal computer to upload or download data files.

Download a file means to retrieve the file from host computer and store into the user's computer.
Upload a file means to send a file from user's computer and store on the host computer.

In WAN, an electronic device modem is used in computers to establish communication over long distance. A modem converts the digital signals into analog signals and vice versa. The modem enable the computer to send and to receive information over long distance through telephone line or microwave system.

Many large organizations make use of WAN.
Example: For example, in Pakistan, the large organizations like PIA, WAPDA, ARMY, NADRA and BANKS etc. use the WAN.

What is WAN - Discribed in Detail