Ethernet cards are available in several different standard packages called form factors:
- Years ago, large ISA cards were the first standard for PCs, requiring users to open their computer case for installation.
- Newer Ethernet cards installed inside desktop computers use the PCI standard and are usually installed by the manufacturer.
- Smaller PCMCIA Ethernet cards that resemble credit cards are readily available for laptop and other mobile computers. These insert conveniently into slots on the side or front of the device. The PC Card is a common PCMCIA device, although only certain PC Card and PCMCIA products support Ethernet.
- Though they look more like small boxes than cards, external USB Ethernet adapters also exist. These are a convenient alternative to PCI cards for desktop computers and also commonly used with video game consoles and other consumer devices lacking PCMCIA slots.
Ethernet cards may operate at different network speeds depending on the protocol standard they support. Old Ethernet cards were capable only of the 10 Mbps maximum speed offered by Ethernet originally. Modern Ethernet adapters all support the 100 Mbps Fast 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 via cables and communicate with Wi-Fi devices via the router.