What is a NIC?

A network interface card/controller (NIC) is a hardware component between a device and cable that enables a device to connect to a network. While traditionally associated with PCs, laptops, and servers, NICs can also exist in networked devices like printers and scanners.

NICs convert the data sent by the computer into a form which can be used by the network cable, transfers that data to another computer, and controls the data flow between the computer and cable. It also translates the data coming from the cable into bytes so that the computer's CPU can read it.

NIC LEDs

A network card usually has two indicator lights (LEDs) for Link and Activity.

Link: This LED indicates whether a network connection exists between the card and the network.

Activity: This LED indicates network activity. Under normal conditions, the light should flicker sporadically and often. Constant flickering may indicate a very busy network or a problem somewhere on the network that is worth investigating.

Typically:

• A solid green LED indicates that the card is receiving electricity and a valid network connection is established

• A flashing light indicates the data is transmitting and there is data activity.

• No light indicates that there is no network connection established.

*There is no standard, so you need to look at the device or check the manual of whatever hardware you are working with*

Below is an example of a NIC: