NIC definition

A NIC (Network Interface Controller) is a module that allows a computer to connect to another networking device over a common medium, typically through an electrical or fibre optic cable (wired) or via radio or microwaves (wireless). Thus NIC's are key components in connecting computers and forming the internet. NIC's can be an embedded package, with external circuitry on the main board, an extension card or an external peripheral connected by USB for example. The main NIC processor merely has to process networking-layer frames (such as ethernet) and exchange data through the module-computer's connection (such as PCI or USB), however many now also handle the hardware-layer networking signals and offload packet (network message) processing for performance and efficiency. Typically a network card or an external peripheral comes with it's own network port or antenna(s) (for wireless).

Wireless networking devices use electromagnetic waves to convey data, as does optical transceivers (both fibre optic and open-space light/infrared), and is most common for WiFi (wireless local area networking) and mobile/cellular telephony. Wired solutions usually provide superior performance, reliability and security, but at the cost of mobility and deployment.