Two of the most common interfaces for wireless network adapters are USB and expansion card slots.
USB Adapters
USB wireless adapters look similar to USB flash memory drives, though some models may have protruding antennas. The advantage of a USB wireless adapter is that it is portable, easy to set up and use, and compatible with a wide variety of computers.
Expansion Cards
A type of wireless adapter that can also be referred to as a wireless network interface card. The two most common standards for expansion cards are Peripheral Component Interconnect (PCI™) and Peripheral Component Interconnect Express (PCIe®), with PCIe being the newer and faster of the two. The advantage of expansion cards is that they are able to support more antennas, which can result in better signal strength. However, compatibility is limited to desktops only.
Wired Network Adapters
Ethernet is the standard that all routers, switches, and hubs use for wired networks. An Ethernet cable closely resembles a telephone cable, except that it contains more wires and has a wider connector. Like wireless network adapters, the two most common interface types for Ethernet adapters are USB and expansion card slots.
Similar to USB wireless adapters, USB Ethernet adapters are easy to install, easy to use, and portable. Some also include additional USB ports, which can offset the fact that they use one port.
For desktops, Ethernet expansion cards can be either PCI or PCIe. While for laptops, Ethernet networking can be added via ExpressCard or PCMCIA card. For both laptops and desktops, the advantage of using an expansion card is that it can free up a USB slot.
Almost all standalone Bluetooth adapters are USB devices, and some PCI/PCIe wireless network adapters may also include Bluetooth functionality. There are several standards for Bluetooth devices, so you should ensure that the wireless adapter you purchase is compatible with the devices that you plan to pair it with.
