What Is an Ethernet Card?

An Ethernet card is one kind of network adapter. These adapters support the Ethernet standard for high-speed network connections using cable connections.

Although they used to be ubiquitous, wired Ethernet ports are gradually being supplanted in computers by Wi-Fi networking capability, which offers adequate speed relative to Ethernet but without the cost of a large port or the hassle of running a cable from an Ethernet jack to a PC.

Ethernet cards are part of a category of computing hardware called network interface cards.

Form Factors

Ethernet cards are available in several standard packages called form factors that have evolved over the last several generations of PC hardware:

  • In the 1990s and early 2000s, large Industry Standard Architecture cards were the first standard for PCs. Computer owners had to open the computer's case to install the ISA card.
  • Newer Ethernet cards installed inside desktop computers use the Peripheral Component Interconnect standard and are usually installed by the manufacturer. PCI cards are still common in desktop PCs for computers whose motherboards do not contain an onboard Ethernet port.
  • Smaller Personal Computer Memory Card International Association Ethernet cards that resemble credit cards are readily available for laptop and other mobile computers. These insert into slots on the side or front of the device. The PC Card is a common PCMCIA device, although only some PC Card and PCMCIA products support Ethernet. By the early 2010s, however, fewer laptops supported the PCMCIA standard.
  • Though they look more like small boxes than cards, external USB Ethernet adapters also fill a market niche. These devices are a convenient alternative to PCI cards for desktop computers, and they're also used with video game consoles and other consumer devices that lack PCMCIA slots.

Networking Speed

Ethernet cards operate at different network speeds depending on the protocol standard they support. Old Ethernet cards were capable only of the 10 Mbps maximum speed originally offered by the Ethernet standard. Modern Ethernet adapters support the 100 Mbps Ethernet standard, and an increasing number now also offer ​gigabit Ethernet support at 1 Gbps (1000 Mbps).

An Ethernet card does not directly support Wi-Fi wireless networking, but home network broadband routers contain the necessary technology to allow Ethernet devices to connect using cables and communicate with Wi-Fi devices using the router.

The Future of Ethernet Cards

Ethernet cards ruled when cables remained the primary form of network access. Ethernet offers consistently more reliable connections than wireless networking and therefore remains popular as a built-in option for desktop PCs and other relatively immobile computers.

Mobile devices including laptops and tablets have shifted away from Ethernet and toward Wi-Fi. The expansion of Wi-Fi services in workplaces, coffee shops, and other public places, and the decline of wired Ethernet connections in modern hotels have reduced the access to wired Ethernet for road warriors — and consequently has reduced the need for Ethernet cards.

  • How do I tell if my network adapter is slowing down the Ethernet speed?

    An Ethernet adapter doesn't slow down a connection even if you add multiple adapters to your network. However, the distance of the adapter from the router does affect the speed; the farther apart they are, the slower the speed.

  • What is an Apple Ethernet Network Adapter?

    Apple manufactures two Ethernet adapters for use with Mac computers: the Thunderbolt to Gigabit Ethernet Adapter and the Apple USB Ethernet Adapter. The company doesn't make an Ethernet adapter for its mobile devices, but it recommends the Belkin Ethernet + Power Adapter for Lightning Connector for this purpose.

Was this page helpful?