27. About Wireless Network Adapters
For a computer to communicate on a wired or wireless network, the computer must be outfitted with a network adapter The network adapter provides the connection between the computer and the network's data transfer medium. On a wired network, the medium is typically copper CAT 5 wire. On a wireless network, the medium is a radio signal.
The network adapter, whether it is wired or wireless, is responsible for taking the data from your computer and converting it into a form (a single stream of data) that can be moved over the network medium. Network adapters actually contain a transceiver (transmitter/receiver), which allows for the conversion and sending of data and also for the receiving and conversion of data (the data is converted when it is received so that it can be processed by the computer).
Data travels in parallel on your computer, much like traffic on a multi-lane highway. When data is transmitted onto the network by a network adapter, such as a WiFi network adapter, the data must be converted from parallel to serial by the adapter. Metaphorically speaking, this is like taking traffic on a multi-lane highway and funneling it down to a single-lane road.
Wireless network adapters can be added to a notebook or desktop computer (if an open expansion slot is available). Most new notebook computers come with a WiFi adapter already installed, and most computer manufacturers provide a WiFi adapter option (which often costs you a little more) for the desktop computers they sell. See Determine Upgradeability of Current Computers for more information about whether your current computer can support a wireless network adapter.
PC processor manufacturers such as Intel and AMD have developed computer processors (the brain of the computer) for notebook computers that are tightly integrated with mobile technology features such as WiFi network adapters. For example, Intel offers Centrino Mobile technology and AMD provides AMD Turion 64 Mobile technology. Any notebook computer that you buy displaying the logo of either of these mobile technologies has been specifically designed for WiFi networking.
In terms of choices related to adding a WiFi adapter to your current computer, you can add a WiFi adapter to an expansion slot or you can use an external WiFi adapter that connects to a USB port on your computer. The best and easiest way to go is to add a USB external WiFi adapter to the computer. Even older computers (including those as old as six or eight years) typically have at least one USB port.
In terms of adding a WiFi adapter to an expansion slot on your computer, the add-on WiFi adapter for a notebook computer varies a great deal from the WiFi adapter that you would add to a desktop computer. Notebook computers typically provide at least one PCMCIA (Personal Computer Memory Card International Association) expansion slot that is used to add items such as network adapters (such as a WiFi card). Upgrading a notebook is a matter of sliding a small (PCMCIA) expansion card into the appropriate expansion slot.
Notebook computers come with one of three types of PCMCIA slots: Type 1, Type 2, or Type 3. Each of these slot types is specific to a card type. Check your notebook documentation to determine the type of slot on your computer. Most WiFi network adapters are Type 2 cards, and most notebook computers provide either a Type 2 slot or a PCMCIA slot that can accommodate multiple card types such as both Type 1 and Type 2. The newest generation of PCMCIA adapter cards for notebooks are typically referred to as CardBus cards.
Desktop computers (including towers) typically provide one or more PCI expansion slots. The Peripheral Component Interconnect (PCI) slot is an expansion slot on the motherboard of a desktop or tower computer and is the standard expansion slot type for Intel-compatible motherboards (the main circuit board for the computer). Upgrading a desktop computer requires that you open the case and install the network adapter in an open PCI slot. As already mentioned, most desktop/tower computers provide a minimum of one or two PCI slots. If you haven't added any peripherals such as a new sound card or video adapter to your computer, you probably have a slot for your adapter card. However, you can be sure only by opening the case and examining the motherboard for available slots.
Because both notebook computers and desktop/tower computers have USB ports, either type of computer can be upgraded to WiFi using an external USB WiFi adapter. Newer computers typically have multiple USB ports; new notebooks typically have at least two USB ports and many desktop computers have USB ports both on the back and front of the computer case. If you want to use an external USB WiFi adapter but are out of USB ports, you can purchase a USB hub that expands the number of available USB ports on your computer. The USB hub, which is typically a fairly small device, connects to one of the existing USB ports on your computer. Additional USB devices (such as a WiFi adapter) can then be connected to the hub.
A USB wireless networking adapter can provide a computer that has an available USB port with the capability of communicating on a wireless network. (Photo courtesy of Netgear.)
As far as the actual selection of a WiFi adapter for your notebook or desktop computer, make sure that you select an adapter that can take advantage of the connection speed your wireless router provides. If you are using a wireless G router (that is, a router made to the specifications of the 802.11g standards), it makes sense to purchase a wireless G network adapter. Although a wireless 802.11b (wireless B) WiFi adapter can connect to a wireless G router/access point, wireless B (with a connection speed of 11Mbps) isn't going to give you the higher speed connection that is provided by wireless G adapters (up to 54Mbps).
Wireless B routers and adapters, which provide a maximum connection speed of only 11Mbps, are really obsolete. You will actually have a tough time finding them. If you do find wireless B devices, you might be tempted to buy them because they are extremely inexpensive. However, wireless G provides connection speeds up to 54Mbps (don't settle for 11Mbps). Wireless G devices (routers, access points, and WiFi adapters) aren't all that expensive and most stores that carry computers stock them.