What is a network interface card (NIC)? Definition from SearchNetworking

A network interface card (NIC) is a hardware component, typically a circuit board or chip, installed on a computer so it can connect to a network. Modern NICs provide functionality to computers, such as support for input/output interrupt, direct-memory access interfaces, data transmission, network traffic engineering and partitioning.

A NIC provides a computer with a dedicated, full-time connection to a network. It implements the physical layer circuitry necessary for communicating with a data link layer standard, such as Ethernet or Wi-Fi. Each card represents a device and can prepare, transmit and control the flow of data on the network.

The NIC uses the Open System Interconnection (OSI) model to send signals at the physical layer, transmit data packets at the network layer and operate as an interface at the TCP/IP layer.

The NIC operates as a middleman between a computer and a data network. For example, when a user requests a webpage, the computer passes the request to the network card, which converts it into electrical impulses.

A web server on the internet receives the impulses and responds by sending the webpage back to the network card as electrical signals. The card receives these signals and translates them into the data that the computer displays.

Network controllers were originally implemented as expansion cards that could plug into a computer port, router or USB device. However, more modern controllers are built directly into the computer motherboard chipset. Users can purchase expansion card NICs online or in retail stores if they need additional independent network connections. When users choose a NIC, its specifications should correspond with the standard of the network.

The term network interface card is often interchangeable with the terms network interface controller, network adapter and LAN adapter.

While the standard NIC is a plastic circuit board that slides into a computer to connect with the motherboard, this connection can occur in multiple ways. Some types of NICs include the following:

Components of NICs include the following:

Editor's note: This article was reformatted to improve the reader experience.