To connect to a network, a computer uses a network interface card (NIC). A NIC controls the wired and wireless connections of a computer to exchange information with other computers and the Internet.
Network Interface Cards
In the early days of computing, individual computers operated as stand-alone systems. The earliest personal computers did not have an easy way to connect to other computers. In order to transfer files between computers, you had to use a portable storage medium such as a floppy disk; however, in modern-day computers, connecting to a network is essential. For example, you need to connect to use e-mail, access information on the Internet, and share documents within a corporate network.
A computer uses a network interface card (NIC) to become part of a network. The NIC contains the electronic circuitry required to communicate using a wired connection (e.g., Ethernet) or a wireless connection (e.g., WiFi). A network interface card is also known as a network interface controller, network adapter, or Local Area Network (LAN) adapter.
Early NICs typically consisted of an expansion card connected to a computer's motherboard. This separate card contained the electronic circuitry and the physical connectors. Here's an example of a typical NIC:
Ethernet Connection
The most widely used network connection for personal computers is an Ethernet connection. Ethernet is really a standard for computer network technologies that describes both hardware and communication protocols. Ethernet was commercially introduced in 1980 and has largely replaced other wired network technologies.
Since Ethernet is so widely used, most modern computers have a NIC built into the motherboard. A separate network card is not required unless some other type of network is used. Here, you can see an Ethernet connection built into a motherboard. Several other connections are located directly adjacent to the Ethernet connection.
An Ethernet connection uses a standard interface known as an RJ45 connector. 'RJ' stands for 'registered jack.'
Ethernet cable using a RJ45 connector
ethernet cable
This cable plugs into the Ethernet connection of a computer. Small LED lights built into the connection will show that a connection is active and whether data is being transferred.