standard 10BaseT (Cat 5) cable. The AP serves as a master station and hub. It transmits
and receives data to and from the 802.11 PCI cards in the networked PCs. There are inter-
nal cards for PCs, like the one shown in Figure 20-13, as well as 802.11 PC Cards used for
notebook and other portable PCs, shown in Figure 20-14. Figure 20-15 shows a WLAN
access point, which is typically about the size of an external modem. Access points can be
mounted on tabletops, walls, and even ceilings.
Themoreaccesspointsonanetwork,thebetterthewirelesscoverageforthenetwork.
In fact, if the access points slightly overlap, it is conceivable that a user could actually
walk down a street, move about a conference center, or sit in a café and remain connected
to the network and even the Internet.
Another wireless network device, the wireless bridge, is used to connect two hard-wired
computer networks that are up to one mile apart. Wireless bridges are used to connect
buildings together to form a single network. Wireless network bridges are normally
connected to an antenna that is mounted outdoors with a clear line of site to the other
bridge’s antenna, located on another building.Bluetooth
Another emerging wireless technology is Bluetooth, which is used to create what is called
a wireless personal area network or WPAN (pronounced “W-pan”). (This technology isChapter 20: Networks and Communications^535
Figure 20-13. An 802.11 (WLAN) network adapter card. Photo courtesy of Nokia