The Flavors of 802.11
This section briefly describes the variants of the 802.11 standard.
It's perfectly possible for a wireless chip to run multiple flavors of 802.11. For example, one of the chipsets available to laptops using Intel Centrino mobile technology runs 802.11b, 802.11g, and 802.11a. This “three-way” Wi-Fi radio will choose the most appropriate 802.11 variant depending on the network it is connecting to and the preferences of the user.
Many Wi-Fi devices currently in operation are using the 802.11b flavor of 802.11 (although the backward compatible and faster 802.11g has replaced 802.11b as the reigning “monarch” of Wi-Fi).
The full 802.11b specification document is more than 500 pages long, but the most important things ...