An Ethernet adapter connects a computer to the Internet or to a local network via a wired connection. Most computers include an Ethernet port on the motherboard and do not require a separate adapter, but some laptops only support Wi-Fi connections out of the box. For these situations, or to replace the integrated network adapter on a desktop computer's motherboard, you can buy and install a separate Ethernet adapter.
Types of Ethernet Adapters
For laptops or desktops without an Ethernet port, you can buy a USB Ethernet adapter that connects externally. Mac computers alternatively support a Thunderbolt Ethernet adapter. Desktop computers can also use internal Ethernet cards, which connect to either a PCI or PCIe slot on the motherboard. Some manufacturers claim their adapters work better and improve system performance, but in most cases, one Ethernet adapter is as good as another.
Using Ethernet Adapters
Ethernet adapters require a driver to operate. Often, the operating system will automatically install a compatible driver after you add an adapter. If the system can't find a driver on its own, you'll need to download the driver from the adapter manufacturer's website. After installation, connect the adapter to an open port on your router -- or directly to your modem -- with an Ethernet cable to connect to a network or the Internet.