Network Interface Controllers (NICs)

• A network interface controller (NIC) is a hardware device that is used to connect a device to a network. Communicating across a network requires electronic digital data to be transferred between points. The NIC converts the data that is to be sent into appropriate signals that can be carried across the medium:

  • In a wired network, these signals will be voltages through a wire, or pulses of light through a fibre
  • In a wireless network, the signals will be modulated radio waves
• The NIC in the sending device is responsible for converting digital data into these signals. At the receiving end, the NIC will receive the signals and convert them back into the corresponding digital data.
• Each NIC has a unique identifier called a Media Access Control (MAC) address. It is 48 bits long, and is usually referred to in hexadecimal notation, for example: cd:f1:24:e4:89:a1. The MAC address is allocated by the manufacturer and cannot be changed.