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The term gateway gets used a lot by different folks with different ideas about what such a device is. Although our definition is the most common (and, in our opinion, correct), you might see some vendors selling devices that they call Internet gateways that don’t have all the functions that we describe. For example, some access points and routers that don’t have built-in broadband modems are also called gateways. We don’t consider these to be Internet gateways because they actually link to the WAN modem. They are more of a modem gateway, but no one uses that term — it just is not as catchy as an Internet gateway. We call them wireless gateways to keep everyone honest. So keep these subtle differences in mind when you’re shopping.
Network interface adapters
Wireless networking is based on radio signals. Each computer or station on a wireless network has its own radio that sends and receives data over the network. Like in wired networks, a station can be a client or a server. Most stations on a home wireless network are desktop personal computers with a wireless network adapter, but they could also be a portable device, such as a laptop or a PDA.
Each workstation on the network has a network interface card or adapter that links the workstation to the network (we discuss these in Chapter 1). This is true for wireless and wireline (wired) networks. In some instances, such as where the wireless functionality is embedded in the device, the network interface adapter is merely internal and pre-installed in the machine. In other instances, these are internal and external adapters that are either ordered with your workstation or device, or which you add during the installation process. We describe these options in the following sections.
Figure 2-2 shows an external wireless networking adapter that is designed for attachment to a computer’s Universal Serial Bus (USB) port, and Figure 2-3 shows an internal wireless networking adapter designed for installation in a desktop computer.
Figure 2-2:
Awireless network
adapter that attaches to a computer’s USB port.
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Figure 2-3:
Awireless network
adapter for installation inside a desktop computer.
PC Cards
When you want to add wireless networking capability to a laptop computer, your first choice for a wireless network interface should probably be a Personal Computer Memory Card International Association (PCMIA) card (also called a PC Card; shown in Figure 2-4). Nearly all Windows and some Mac notebook/laptops have PCMCIA ports that are compatible with these cards. (An AirPort card is a special type of PC Card. In Chapter 8, we tell you more about the AirPort card and how to set up a wireless Mac network.)
Figure 2-4:
A PC Card wireless network adapter.
All wireless PC Cards must have an antenna so that the built-in radio can communicate with an access point. Most have a built-in patch antenna that’s enclosed in a plastic casing that protrudes from the PC while the card is fully inserted. At least one manufacturer offers a retractable antenna that’s less likely to get damaged when not in use.
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PCI adapters
Nearly all desktop PCs have at least one Peripheral Component Interconnect (PCI) slot. This PCI slot is used to install all sorts of add-in cards, including network connectivity. Most wireless NIC manufacturers offer a wireless PCI adapter — a version of their product that can be installed in a PCI slot (see Figure 2-5).
Figure 2-5:
A wireless
PCI adapter.
Some wireless PCI adapters are cards that adapt a PC Card for use in a PCI slot. The newest designs, however, use a mini-PCI Card that’s mounted on a full-size PCI Card with a removable dipole antenna attached to the back of the card.
USB adapters
The USB standard has over the last several years become the most widely used method of connecting peripherals to a personal computer. First popularized in the Apple iMac, USB supports a data transfer rate many times faster than a typical network connection and is, therefore, a good candidate for connecting an external wireless network adapter to either a laptop or a desktop computer. Several wireless networking hardware vendors offer USB wireless network adapters. They are easy to connect, transport, and reposition in order to get better reception.
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Most computers built in the last two or three years have at least one (and usually two) USB port(s). If your computer has a USB port and you purchased a wireless USB network interface adapter, see Chapter 7 for more on setting up that adapter.
USB wireless NICs are sometimes a better choice than PC Cards or PCI cards because you can more easily move the device around to get a better signal, kinda like adjusting the rabbit ears on an old TV. If a computer doesn’t have a PC Card slot but does have a USB port, you either need to install a PCI adapter or select a USB wireless network adapter.
Note that there are two forms of USB adapters: ones that have cables and ones that don’t. The cabled USB adapters allow for positioning of the antenna; the non-cabled ones directly connect in a fixed way into the back of your computer, and are designed for economy of size. You might hear either of these form factors referred to as dongles. (See Chapter 5 for more about form factors.)
CF cards
With the growing popularity of handheld personal digital assistant (PDA) computers, the newest category of wireless network adapters uses a Compact Flash (CF) interface to enable connection to PDAs. With a Compact Flash card, such as that from SMC shown in Figure 2-6, you can connect a Pocket PC to a wireless home network. (For more about PDAs and how they can enhance your wireless home network experience, check out Chapter 1.)
Figure 2-6:
A Compact Flash card wireless network interface card.
CF cards are small, 11⁄2"-wide electronic modules that you insert into a CF card slot. The CF card slot where you insert the card is an 11⁄2" slot in the top edge of the Pocket PC. Compact Flash refers to the technology used to store software or other data on the device. Many users employ CF cards to expand the memory in their Pocket PCs and for many other PDA add-ons.