Devices designed to exchange data without using wires require two basic components: a wireless transmitter and paired receiver. The wireless transmitter might broadcast using radio frequency (RF) waves, or it might transmit data on the infrared (IR) wavelength. The paired receiver listens for the signal accordingly. Some examples of products that use a wireless transmitter include routers, computers, cell phones, personal digital assistants (PDAs) and wireless headphones.
The home or office wireless local area network (WLAN) includes a router with an integrated wireless transmitter and receiver. Most routers also have a built in modem so that a single, high-speed Internet account can be shared with all connected computers. Instead of Ethernet cabling connecting the computers, each machine has a wireless network card (or wireless adapter) with its own transmitter and receiver on board. Now an individual computer can transmit a request for data, for example, to the router, and the router can receive the request, forward it to the right party, then transmit the return reply.
The broadcast range for a WLAN varies depending on the building (some materials block RF signals), the hardware and the wireless standard being used, but generally starts at about a 300-foot (91.4m) radius. A different type of wireless network is used to connect devices across short distances of less than 30 feet (9.1m).
Bluetooth® technology is standard on most personal electronics today, including cell phones and PDAs. Bluetooth®-enabled products incorporate a wireless transmitter and receiver to communicate with one another using Bluetooth® standards. The type of network created is called a personal area network (PAN).
Since a PAN is designed to use with battery-operated devices, it is not as robust as a WLAN, as the strength it would take to broadcast over large distances would drain the batteries too quickly. The advantage of a PAN, however, is that it is extremely simple to get two devices talking to each other, with just a few clicks, and distance isn’t an issue when sending files from one personal device to another.
Bluetooth® can be used to send print jobs wirelessly from a laptop to a printer, for example, or to send files from one cell phone to another. You might also synchronize your PDA with your computer using Bluetooth® to rid yourself of the clutter created by a cradle or docking station. Bluetooth® adapters are available for computers and printers that don’t have this capability built in. Most adapters take the form of a USB dongle or key, as a wireless transmitter and receiver can be very small.
While PANs and WLANs use RF waves, wireless headphones use RF or infrared, depending on the model. In either case the wireless transmitter is cabled directly to the audio source, such as a television or home entertainment receiver using auxiliary audio-out ports. The transmitter then broadcasts the stereo audio signals wirelessly to a paired set of headphones that include a receiver. This eliminates a cord running from the headphones to the audio source.
Wireless headphones are extremely convenient, but there are some considerations. RF models can have problems with electrical interference, while infrared or IR models require line-of-sight operation. Some models also have on-board digital processing to create surround sound effects from the stereo signals fed to the transmitter.
Wireless products are available everywhere electronics are sold. Before purchasing personal electronics or office equipment, you might want to check that wireless technology is built-in, if applicable. Older or less expensive models might not include it.
