Network Interface Cards (NIC) are adaptors attached with a computer (or other network device such as printer) to provide the connection between the computer with the network. Each NIC is design for a specific type of network such as Ethernet, Token Ring, FDDI or wireless LAN.

The NIC operates using the physical layer (layer 1) and data link layer (layer 2) specifications. NIC basically defines the physical connection methods with the cable and the framing methods used to transmit bit streams over the network. It also defines the control signals that provide the timing of data transfers across network. The most popular data link layer protocols are Ethernet CSMA/CD, Token Ring etc.

NICs have their own CPU (central processing unit) and RAM (random access memory). NICs can be installed internally or externally, although an internal installation is more popular (Now, almost every PC may install at least one NIC). Typically, a NIC has a unique address to ensure that every NIC can be uniquely identified. In the case of Ethernet, it is called MAC address.

NIC: Network Interface Card

Related Terms: CSMA/CD, MAC address, Ethernet, Token Ring

Reference Links: http://www.erg.abdn.ac.uk/users/gorry/course/lan-pages/nic.html: Network Interface Card