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How the Ethernet port works

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By Muwanguzi Betty


An Ethernet port (aka jack or socket) is an opening on computer network equipment that Ethernet cables plug into. Their purpose is to connect wired network hardware in an Ethernet LANmetropolitan area network (MAN), or wide area network (WAN).


You might see an Ethernet port on the back of a computer or the back or side of a laptop. A router usually has several Ethernet ports to accommodate multiple wired devices on a network. The same is true for other network hardware like hubs and modems.

An Ethernet port accepts a cable that has an RJ-45 connector. The alternative to using such a cable with an Ethernet port is Wi-Fi, which eliminates the need for both the cable and its port.

 Ethernet Ports

An Ethernet port is a little wider than a phone jack. Because of this shape, it's impossible to neatly fit an Ethernet cable into a phone jack, which makes it a little easier when you're plugging in cables. You can't really plug it into the wrong port.


In the picture below, the Ethernet cable is built the same way, usually with a clip to hold the cable into the Ethernet port.



Ethernet Ports on Computers

Most desktop computers include one built-in Ethernet port for connecting the device to a wired network. A computer's built-in Ethernet port is connected to its internal Ethernet network adapter, called an Ethernet card, which is attached to the motherboard.

Laptops usually have an Ethernet port too, so that you can hook it up to a network that doesn't have wireless capabilities.

 How to Troubleshooting Ethernet Port Issues?

If you have internet connectivity issues on your computer, the Ethernet port is probably the first place you should look.

  1. Network cable are unplugged. This condition often results in errors like 'A network cable is unplugged.' You might see such error messages especially if the computer or laptop was recently moved, which can easily knock the cable out of the Ethernet port.                                                                                                         
  2. Network card has come unseated. If you've moved your computer around, in rare cases, the Ethernet card may have come unseated from the expansion slot on the motherboard.
  3. Corrupt or missing network card drivers. Something else related to the Ethernet port is the network driver for the network card, which can become outdated, corrupt, or missing. One of the easiest ways to install a network driver is with a free driver updater tool.

Ethernet Ports on Routers All popular broadband routers feature Ethernet ports, usually a few of them. With this setup, multiple wired computers in a network can reach the internet and the other connected devices on the network.

An uplink port (also called WAN port) is a special Ethernet jack on routers that are used specifically for connecting to a broadband modem. Wireless routers include a WAN port and typically four additional Ethernet ports for wired connections.

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