Wireless LAN Client Adapters (CB21AG and PI21AG) are radio modules that provide wireless data communications among fixed, portable, and mobile devices within both wireless and wired network infrastructures. The client adapters are fully compatible when used in devices supporting "plug-and-play" technology.
You can use AIR-PI21AG, An IEEE 802.11a/b/g-compliant 2.4- and 5-GHz 54-Mbps client adapter card radio module that can be inserted into any device equipped with an empty PCI expansion slot, such as a desktop personal computer