Wireless PANs make use of both radio and infrared light technologies, which manufacturers embed in many different types of devices.
Wireless PANs don't require much battery power to operate, making them ideal for small user devices, such as audio headsets, cell phones, PDAs, game controls, GPS units, digital cameras, and laptops. Figure 4-1 illustrates several of these types of devices. For example, a wireless PAN enables someone to listen to music on headsets wirelessly from their PDA. Or a person can transfer his phone book from his laptop to a cell phone. As with these cases, wireless PANs eliminate wires that often frustrate users.
Radio NICs are available for wireless PANs in PC Card and Compact Flash (CF) form factors. If you have a laptop, for example, it's easy to add wireless PAN connectivity by installing a PC Card. These products are available from different vendors. Many of the newer PDAs and laptops come equipped with one or more wireless PAN interfaces. This makes these wireless devices ready to connect with other devices, such as printers, PDAs, and cell phones that also have wireless PAN interfaces. The larger PC Cards are uncommon for wireless PANs, mainly because wireless PAN technologies are ideal for small devices.
Several companies offer a wireless PAN USB adapter (see Figure 4-2), which is also called a wireless dongle. For example, you can purchase a USB Bluetooth adapter and connect it to a USB port on your PC. This makes the PC able to synchronize with other devices having Bluetooth connectivity. Bluetooth?which is discussed later?is a specification developed for short-range, radio-based transceivers.
A PDA utilizing Bluetooth can wirelessly interface with the Bluetooth-enabled PC and synchronize without placing the PDA in a synchronization cradle. A USB connection over Bluetooth, however, is generally slower than having a directly wired interface through the PC's USB port. This is because the wireless USB adapter is mapped to the PC's serial port, which runs slower than the USB port. The wireless solution might be more convenient, but you might need to wait twice as long before synchronization is complete.
Most wireless PAN applications simply involve cable replacement, but some vendors sell Bluetooth-equipped routers to support wireless connections to the Internet. Because of limited range, though, these wireless PAN routers are primarily for home and small office use. In order to satisfy more connectivity needs, some wireless PAN routers also support wireless LAN interfaces, such as 802.11.