The Book of Wireless, Second Edition

Network Adapters

A network adapter is the interface between a computer and a network. In a wireless network, the adapter contains a radio transmitter that sends data from the computer to the network and a receiver that detects incoming radio signals that contain data from the network and passes it along to the computer. The computer's operating system treats a wireless adapter just like any other network interface.

If you only plan to use Wi-Fi to connect your computer to the Internet through existing Wi-Fi hot spots in public locations, such as libraries, coffee shops, and so forth, a network adapter (along with the software to support it) is the only new hardware you need to add to your computer. If you want to set up your own home or office ...