Network Interface Cards: What They Are and Where to Buy Them

What are network interface cards? 

The network interface card (NIC) is hardware installed in your computer that lets you connect your devices to communicate over a computing network or servers via ethernet. It provides wired or wireless communication with local area networks (LAN) or with the large-scale network through internet protocol (IP). NIC cards work on the OSI framework's physical layer one and data link second layer.

The NIC circuitry communicates with the physical and data link layers to connect you to the network. These cards are sometimes called network interface controllers, network adapters, or LAN adapters.

Read more: OSI Model: An Overview

How do NICs work? 

Think of the NIC as a translator. Whenever you visit a website or send an email, your computer sends a request for that information. The NIC takes that request and converts it into a language that the network can understand. It packages the request into data packets and sends them over the network.

It receives packets from the network, breaks them into understandable pieces, and sends them to your computer. This action lets you see web pages, receive emails, or download files. 

Every NIC has a media access control (MAC) number, a unique identifier assigned by the manufacturer. The MAC identifies the NIC's computer on the network. Some confuse the NIC with a broadband or internet card, but broadband cards connect your device wirelessly to a network. A network interface card connects to a router or network switch via a direct connection.

Read more: What Is a MAC Address?

Different types of NICs 

There are two main types of network interface cards: the NIC that comes included internally with your device and a wireless NIC found in laptops or other portable devices. The latter connects to Bluetooth or Wi-Fi using an antenna to communicate using radio waves to allow wireless communication between the device and broader networks. 

When your internal NIC isn’t enough, an external network expansion card improves connectivity speed and reliability and expands the device’s connectivity.

Read more: 6 Network Certifications for Your IT Career

NIC components

The NIC has six parts. Each plays a role in the card’s translator role.

• Controller: The processing unit that decides how the NIC performs

• Boot read-only memory (ROM) socket: Enables the card to store instructions for its function permanently

• NIC port: Typically connects to an Ethernet cable to transmit and receive signals

• Bus interface: Connects the card into the expansion slot for the device it serves

• LED indicators: Indicators that help identify the card’s status to the connected network

• Profile bracket: Helps affix the NIC in its slot on the computing device

When and where to use a NIC 

Network cards can provide more quick, efficient, and secure communication, making the wired NIC connection a popular choice in homes and professional settings. Traditionally associated with desktops, laptops, and servers, NICs can also be found in printers, scanners, smartphones, smartwatches, and other connected devices. 

Many users are unaware the NIC is in their device as it’s part of the computer hardware. If you customize your network or server configuration or build your own computers, you will pay more attention to their choices when buying and installing NICs.

Read more: What Is the Internet of Things (IoT)? With Examples

Where and how to buy a NIC

You can buy network interface cards at several locations online, like Amazon, NewEgg, Best Buy, and Office Depot. With so many types of NICs for various buses, ports, connection types, and different networking speeds and operating systems, prices range from about $20 to $200. Follow these steps for some tips on how to buy the suitable NIC for you:

1. Choose the appropriate bus. To do this, look at the slots on your device or research the connection in the manual. The primary options include PCI, PCI-X, PCIe, and USB.

2. Now, you can select your NIC speed. You’ll typically be looking at 10/100/1000 Mbit/s NICs. That means they can transfer data at 10, 100, or 1000 Megabits per second. Some NICs even support 10, 25, and 40 Gigabit connections. The bus you choose can limit your speed options, so select the NIC card that can support your network needs.

3. Choose the number of ports. A card can have one or more ports, which may prove useful if you have a particular networking need. Typically, you’ll choose from one, two, or four ports.

4. Consider how the card will connect. You can pick from several options, including Ethernet, DAC, MPO, MTP, and more. 

5. Confirm your choice works with your operating system. Many NICs work with several systems, but always check first.

Learn about networking on Coursera

Network interface cards are essential to any computing or server environment because they provide fast, reliable, and secure connections to LANs, routers, and switches. Choosing the suitable NIC for your system is vital to accessing NICs' benefits. To learn more about networking hardware, start with The Bits and Bytes of Computer Networking from Google. It’s just one of several courses within the Google IT Support Professional Certificate program on Coursera. Upon completion, gain a shareable Professional Certificate to include in your resume, CV, or LinkedIn profile.