How Does a Network Card Work?

Ray Bouknight/CC-BY 2.0

A computer’s network card works by taking the data given to it by the CPU and sending it to a destination. It translates the data into a form that can be transferred via cables and then translates the data it receives back into data usable by the computer.

Network interface cards receive this data from buses on the computer’s motherboard, typically those that send information toward the peripheral slots. The information is converted from a parallel structure to a linear structure by the network card, so it can readily transmit along cables. Once the network card receives the address for the destination device, the data is sent. Information sent back is then converted back into parallel structure and redistributed along the motherboard’s buses, so the CPU can process the received data.

Network cards can have multiple identifying addresses and can connect to several different networks at the same time. The process of managing what data goes to which address on which network is controlled by the network card. Other devices, such as printers, tablets and external hard drives can have their own network cards, and they can be designed to communicate with only specific networks. Every device on a network frequently broadcasts its address automatically, so transmitting data is easy.