jump to article
AFB  ®
Technology News for People Who Are Blind or Visually Impaired
From the American Foundation for the Blind
 September 2005 Issue  Volume 6  Number 5

Access Issues

Untangling the Wireless World

These are certainly the days of portability. Cell phones, laptop computers, personal digital assistants (PDAs), and MP3 players are all battery-powered devices that we can carry around with us to provide productivity and entertainment on the go. Many of these devices are able to communicate with other equipment, frequently without the need for wires. Wireless connectivity is all the rage, but the variety of wireless technologies can easily overwhelm you. Just what is Bluetooth good for? Do I need an infrared port on my PDA? How can I connect to the Internet without wires? The answers to all these questions can help you to select a portable computer, cell phone, or other device, but it can be difficult to sort out the pieces of the connectivity puzzle. This article removes some of the mystery from the strange-sounding names in the connectivity game. I begin by discussing infrared, a technology that has been in existence since the advent of modern television remote controls and has proved surprisingly useful in moving data between pieces of computer equipment. Then I explain Bluetooth, Wi-Fi, and Wimax, all of which use high-frequency radio waves to get the networking job done. Finally, I tell you a little about how to put the different technologies to use. Hang onto your keyboard. Here we go!

Infrared: The "Light" That Talks

Infrared wireless technology has been with us for many years. It is what permits your television remote control to turn your television on and off and to change channels. Infrared radiation is similar to visible light, but its wavelengths are too long for the human eye to see. The fact that infrared radiation is similar in wavelength to visible light means that it behaves much like visible light. Infrared tends to be "line of sight," which means that it does not transmit around corners well and does not pass through walls. This fact limits infrared's uses, but it also means that infrared signals are hard for someone at a distance to intercept.

Typically, a device that is capable of infrared communication will have a small lens that is located somewhere on its outer surface, in a place where it is fairly easy to aim the infrared port at other infrared-capable devices. Infrared ports usually have both a transmitter and a receiver, so that two gadgets can "talk" and "listen" at the same time.

So what is infrared used for in the world of today's portable devices? Well, actually, there are a surprising number of situations in which line-of-sight connections between devices can get the job done. Laptop computers and PDAs can transmit files back and forth just by having their infrared ports pointed roughly at each other (and having the right commands given to the two devices to start the data transfer). E-mail and address books can be synchronized between a portable computer and your desktop. Electronic "business cards" can be exchanged between computers without the need for cables. There are also microphones, headsets, modems, and printers that can be connected using infrared links. Where the distances are relatively short and direct, infrared is a solid, reliable, and secure option for a variety of communications.

Bluetooth: The Networker from the North

Bluetooth was the nickname of a Viking king of the early 900s. King Bluetooth is famous for having unified the people of the Danish region of Europe. Bluetooth is now also the name of a short-range wireless technology that is intended to "unify" (or, at least, connect) electronic devices into little networks that cooperate automatically.

Bluetooth is amazing for its flexibility and ease of use. Put a Bluetooth headset near a Bluetooth cell phone, and the two will strike up a conversation, allowing the headset to act as the mouth- and earpiece for the cell phone--all with no wires and low transmitter power, as little as a milliwatt. Put a Bluetooth computer near a Bluetooth printer, and the two will recognize each other and know how to handle printing your latest novel. Bluetooth devices cooperate by forming little networks of from two to eight devices, with one network member acting as the main controller or "master." This master invites other Bluetooth devices in the area to join the network as "slaves." Again, all this happens automatically, with minimal setup on the user's part. Clearly, Bluetooth permits equipment to connect for a wide variety of purposes. As the newer and faster Bluetooth version 2.0 standard becomes widespread, it is likely that more audio components and household appliances will be able to work together wirelessly over Bluetooth.

You Talk Too Much

The downside of Bluetooth, ironically, is also its greatest strength: its readiness to strike up a conversation with any other Bluetooth device in the area. Go to a crowded place with your Bluetooth-equipped cell phone, and you may find that someone else's headset is suddenly connected to your phone. Of course, you, too, could find your own Bluetooth equipment unexpectedly connecting to someone else's equipment as well. This is radio, after all, and radio signals do not always do what you expect.

Wi-Fi: Networking Without Wires

Wi-Fi stands for "wireless fidelity." Wi-Fi is a set of high-frequency radio standards for networking computer equipment over distances of up to a few hundred feet. Wi-Fi has some similarities to Bluetooth in that it also uses high-frequency radio signals to connect devices. However, Wi-Fi is used more specifically to create local area networks (LANs), such as are used in offices, or to permit home computers to share files, printers, or Internet connections. Where network cables or telephone lines have traditionally been used to connect a computer to a LAN or the Internet, Wi-Fi offers a more flexible option. Wi-Fi has become so popular as a way to get on the Internet that many businesses and communities have set up Wi-Fi connection points, known as "hot spots," as a service to their customers and visitors. The term Wi-Fi was coined by an organization called the Wi-Fi Alliance, which certifies Wi-Fi products for their compliance with its standards. As Wi-Fi standards have evolved, several variations or "flavors" of Wi-Fi have developed. This is an important point because it affects whether a Wi-Fi device will be able to work on any particular Wi-Fi network.

Security Is Vital!

Many people use Wi-Fi to form their home computers into small networks. It is important to ensure the privacy of such a network by using one of the available privacy techniques, such as wired equivalent privacy (WEP) or Wi-Fi protected access (WPA). WEP is widely available, but it is significantly more vulnerable to eavesdropping than is the newer WPA. As you can imagine, the more you use your wireless connection, the more prone it is to eavesdropping. A newer refined encryption standard, known as IEEE 802.11i or WPA2, was ratified as a draft standard in June 2004. It uses improved encryption compared to WPA and was designed specifically to address the weaknesses of WEP. At this writing, however, it is difficult to find products that feature support for WPA2, so WPA seems to be the security standard of choice at present.

Wimax: Wireless Broadband in the Works

Wimax is a coalition of players in the wireless networking business. Like the Wi-Fi Alliance, this group has worked to advance standards in wireless networking, but in the case of Wimax, the intent is to develop standards for access to broadband networks over longer distances--up to 30 miles. Wimax is considered to be a particularly attractive option for providing Internet access to rural areas, where cable and other wired options may be hard to come by. However, Wimax products are only beginning to appear, and it remains to be seen just what role Wimax will play in the overall wireless networking game.

Making the Connection

I have described a number of types of wireless connectivity. Now I will discuss how a person may take advantage of these different networking options.

Infrared ports have been available on computers, especially laptops and, more recently, PDAs, for several years. They are usually built into a device and use a lens on the surface of the case to talk to other devices. Other infrared-compliant appliances generally have the infrared built in, and the devices generally need to point roughly toward one another to communicate. You should be able to tell if a piece of equipment includes an infrared port by reading the system's specifications. Infrared is used a lot to share files and contact information between computers. For example, businesspeople in a conference room will often pass documents to one another via their infrared ports. Infrared can offer a quick connection to a printer as well. An interesting application of infrared is the program being developed for the Freedom Scientific PAC Mate PDA that will allow it to act as a television remote control, taking us full circle to where infrared began, in a way.

Bluetooth is truly the no-muss, no-fuss option for connecting equipment that has a reason to work together. You could think of Bluetooth as being, for portable devices, what plug-and-play was supposed to be for the personal computer. Bluetooth-capable equipment, such as telephones and headsets, typically have the Bluetooth capability built in and included in the specifications. Add-on Bluetooth cards may or may not be needed to add Bluetooth to a computer. HumanWare's BrailleNote PK has Bluetooth capability built in, while Freedom Scientific's PAC Mate can have Bluetooth added by using a CompactFlash plug-in card.

If you want to build a network of computers without stringing wires, then Wi-Fi is the obvious choice. Wi-Fi is usually an optional add-on for computers. Several companies sell plug-in Wi-Fi cards. For home networking purposes, a device, such as a wireless router, is generally needed to connect to the Internet and to give the computer something to connect to. As I mentioned earlier, it is important to pay attention to what types of Wi-Fi are supported by a card or router. Read equipment specifications carefully to ensure that the devices that you want to communicate with each other are capable of the needed type of connection and wireless security protocol. This way, your connection will work effectively and will be protected from anyone in the vicinity who may want to listen in on your network.

Wimax is still a while off as an option for most of us, and it remains to be seen just how effective it will be as a long-distance networking option. Your best bet is probably to keep up with the news and the electronics catalogs and web sites to see what role Wimax will play in the years ahead.

Wireless connectivity is popular both in freeing us from our desks and in reducing the unsightly clutter of crisscrossing bundles of wires. As with older wireless media, such as radios and cell phones, we need to ensure that the connections we set up are effective and that we are avoiding unwanted eavesdropping and interference. One thing is sure: Wireless options will only increase in the years ahead.

For More Information

Here are some web sites with good information on wireless networking:

  • <www.whatis.com> contains definitions and background articles for all the wireless technologies discussed in this article.
  • <www.wi-fiplanet.com> contains business information and articles on Wi-Fi and Wimax.
  • <www.networkworld.com> contains late-breaking news and articles on networking technologies and concepts.
  • <www.wikipedia.org>, a user-edited, free-of-charge encyclopedia, contains remarkably in-depth articles on the different networking standards.

Previous Article | Next Article | Table of Contents

Copyright © 2005 American Foundation for the Blind. All rights reserved. AccessWorld is a trademark of the American Foundation for the Blind.

Download the free AccessWorld appDownload the free AccessWorld app
 
Braille-ready fileBraille-Ready File
Back Issues
Search AccessWorld
AccessWorld Alerts Signup
For Advertisers
Contact AccessWorld
 

Related Links

Technology
AccessWorld Appliance Accessibility Guide
Product Search
AFB Consulting
 
 Advertising
Blaze EZ Multiplayer with OCR

Orion TI-84 Plus Talking Graphing Calculator

Did you know there is a direct link between total blindness and a sleep pattern that is out of sync with the 24-hour day? NON-24 a circadian rhythm disorder

Low Vision Simulators Plus VSRT (Pepper) Test LUV Reading Workbook

Cover for Physical Education and Sports for People with Visual Impairments and Deafblindness:Foundations of Instruction
 
 End of advertising