Section A.1. 802.11: The Mother of All IEEE Wireless Ethernet

A 1 802 11 The Mother of All IEEE Wireless Ethernet

The first wireless standard to be defined in the 802 wireless family was 802.11. It was approved by the IEEE in 1997, and defines three possible physical layers: Frequency Hopping Spread Spectrum (FHSS) at 2.4 GHz, Direct Sequence Spread Spectrum (DSSS) at 2.4 GHz, and Infrared. 802.11 could achieve data rates of 1 or 2 Mbps. 802.11 radios that use DSSS are interoperable with 802.11b and 802.11g radios at those speeds, while FHSS radios and Infrared obviously are not.

The original 802.11 devices are increasingly hard to come by, but can still be useful for point-to-point links with low bandwidth requirements.

A.1.1. Pros

  • Very inexpensive (a few dollars or even free) when you can find them.
  • DSSS cards are compatible with 802.11b/g.
  • Infrared 802.11 cards (while rare) can offer interference-free wireless connections, particularly in noisy RF environments.
  • Infrared also offers increased security due to significantly shorter range.

A.1.2. Cons

  • No longer manufactured.
  • Low data rate of 1 or 2 Mbps.
  • FHSS radios are incompatible with everything else.

A.1.3. Recommendation

802.11 devices can still be useful, particularly if you find that you already have a few on hand. But the ever falling price of 802.11b and 802.11g gear makes the old 802.11 equipment less attractive each day. The FHSS and Infrared cards talk only to cards of the same era, so don't expect them to work outside of your own projects. Infrared requires an absolutely clean line of sight between devices and offers limited range, but it operates well away from the popular ISM and UNII bands. This means that it won't interfere with (or see interference from) other networking devices, which can be a huge advantage in some situations.

I probably wouldn't go out of my way to acquire 802.11 equipment, but you can still build a useful network if it's all you have to work with. They are probably best used for building point-to-point links, but might be better avoided altogether.

Bluetooth, Mobile Phones, and GPS

Network Discovery and Monitoring

Wireless Security

Hardware Hacks

Software Hacks

Do-It-Yourself Antennas

Wireless Network Design

Appendix A. Wireless Standards

Appendix B. Wireless Hardware Guide

Wireless Hacks
Wireless Hacks: Tips & Tools for Building, Extending, and Securing Your Network
ISBN: 0596101449
EAN: 2147483647
Year: 2004
Pages: 178 © 2008-2020.
If you may any questions please contact us: