How to Tell If Computer Has an Ethernet Card?

Identify all ports and jacks on your computer. To tell if your computer has an ethernet card, you can look for an ethernet jack on your computer's back panel. To do this, though, you must be able to tell the difference between an ethernet jack and the other ports and jacks on the back of your computer. The ethernet jack is shaped similar to a telephone jack and will have an LED light next to the jack. Your computer may also label the jack with the word "Ethernet" or "Ether" directly above the jack.

Distinguish the ethernet jack from the modem jack. If your computer does not have labels on its ports/jacks and your computer is equipped with a modem, you may have difficulty distinguishing between the modem jack and the ethernet jack. Both jacks are shaped similarly, but the ethernet jack is wider and shaped more like a rectangle. The modem jack is smaller and square-shaped. If your computer does not have labels on its port but uses symbols instead, you can distinguish between the ethernet jack and the modem jack by seeing which jack has a telephone symbol above it. This will be the modem jack. If your computer has only one jack and it is square-shaped as opposed to rectangular, your computer does not have an ethernet card.

Find the ethernet PCI card from inside the computer. You can tell if your computer has an ethernet card by looking at the internal hardware of your computer. First, power off and unplug your computer. Using a Phillips screwdriver, unscrew and remove the outer case of your computer. Locate your computer's motherboard and examine all of the PCI cards that are in its PCI bus slots. If your computer is equipped with an ethernet card, you will find a rectangular-shaped PCI card that has a large black or gray box at the connector end of the PCI card. This box is where the ethernet cable is to be plugged into your computer. If you do not see a PCI card like this, your computer does not have an ethernet card.

Use your operating system to check for an ethernet card. Another way you can determine if your computer has an Ethernet card is to see if a network adapter is in your operating system's list of hardware devices. In Windows, do this by accessing the "Device Manager." Right-click the "My Computer" icon on your PC, then click "Properties." Select the "Hardware" tab in the "System Properties" dialog box that appears, then select "Device Manager." Scroll down the list of devices until you see the "Network Adapters" heading. Click the "+" symbol next to "Network Adapters" to expand the list to see if it lists an ethernet adapter. If no device is listed, your PC does not have an ethernet card. In Mac OS X, search for a network adapter by opening the "Apple" menu, then clicking "System Preferences," "View," then "Network." When the "Show" menu loads, click "Active Network Ports" to see if your Mac lists an ethernet card. If it does not, the computer does not have an ethernet card.