The network card is equipped with processor and memory (including RAM and ROM).Communication between network card and local area network is performed by serial transmission via cable or twisted pair.Communication between network card and computer is carried out in parallel through I/O bus on computer main board.An important function of the network card is therefore to perform a serial/parallel conversion.Since the data rate on the network is different from that on the computer bus, a memory chip that caches the data must be installed in the network card.
Network cards were previously plugged into the computer bus as extension cards, but due to their low cost and the prevailing Ethernet standards, most new computers have integrated network interfaces on the main board.These boards either integrate Ethernet functionality into the main board chip or use a cheap network card connected to the main board via PCI (or an updated PCI-Express bus).Unless multiple interfaces are required or other types of networks are used, a separate network card is no longer required.Even the updated motherboard may contain a built-in dual network (Ethernet) interface.
With the continuous improvement of integration, the number of chips on network cards is decreasing. Although there are many kinds of network cards produced by different manufacturers, their functions are quite different.