Wireless local area networks (WLANs) function much like conventional LANs, except that the information they carry is transmitted using radio-frequency (RF) signals and sometimes infrared signals rather than copper or fiberoptic cables. Using devices that communicate over a WLAN has several benefits: For example, the devices can be used virtually anywhere in the facility without needing access to a hardwired data terminal, and they are often easier to install since they don't need additional wiring. But WLANs also have drawbacks. They can't transfer as much data at one time as wired systems, for example, or transfer it as quickly. Because they require new technology, they may carry greater costs. And because they operate in a frequency band that isn't protected from interference, they require special techniques to maximize the quality of their signals--techniques that, themselves, require a number of challenging decisions. In this article, we describe the basic operating and purchasing considerations involved in deciding whether to invest in WLAN technology and which type of system to choose.
