Network interface cards, commonly referred to as NICs, are used to connect a PC to a network. The NIC provides a physical connection between the networking medium and the computer’s internal bus, and is responsible for facilitating an access method to the network (OSI Layers 1 and 2).
Most NICs are designed for a particular type of network, protocol, and media, although some can serve multiple networks. Cards are available to support almost all networking standards, including the latest Fast Ethernet environment. Fast Ethernet NICs are often 10/100 capable, and will automatically set to the appropriate speed. Full-duplex networking is another option, where a dedicated connection to a switch allows a NIC to operate at twice the speed.