Linksys WPC54GS manual What is ISM band?, What is Spread Spectrum?

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Wireless-G Notebook Adapter with SpeedBooster

maintain contact with the wireless network even when not actually transmitting data. Achieving these functions simultaneously requires a dynamic RF networking technology that links access points and nodes. In such a system, the user’s end node undertakes a search for the best possible access to the system. First, it evaluates such factors as signal strength and quality, as well as the message load currently being carried by each access point and the distance of each access point to the wired backbone. Based on that information, the node next selects the right access point and registers its address. Communications between end node and host computer can then be transmitted up and down the backbone.

As the user moves on, the end node’s RF transmitter regularly checks the system to determine whether it is in touch with the original access point or whether it should seek a new one. When a node no longer receives acknowledgment from its original access point, it undertakes a new search. Upon finding a new access point, it then re-registers, and the communication process continues.

What is ISM band?

The FCC and their counterparts outside of the U.S. have set aside bandwidth for unlicensed use in the ISM ism band: radio bandwidth utilized in wireless transmissions. (Industrial, Scientific and Medical) band. Spectrum in the vicinity of 2.4 GHz, in particular, is being made available

worldwide. This presents a truly revolutionary opportunity to place convenient high-speed wireless capabilities in the hands of users around the globe.

What is Spread Spectrum?

Spread Spectrum technology is a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communications systems. It is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the trade-off produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread-spectrum signal looks like background noise. There are two main alternatives, Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).

What is DSSS? What is FHSS? And what are their differences?

Frequency-Hopping Spread-Spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise. Direct-Sequence Spread- Spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered. Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers.

spread spectrum: wideband radio frequency technique used for more reliable and secure data transmission.

dsss: Frequency transmission with a redundant bit pattern resulting in a lower probability of information being lost in transit.

Appendix A: Troubleshooting

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Frequently Asked Questions

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Contents Wireless- G Word definition Copyright and TrademarksTable of Contents Front Panel List of Figures21 EAP-MD5 Authentication Welcome IntroductionAdapter a device that adds network functionality to your PC What’s in this Guide? Wireless-G Notebook Adapter with SpeedBooster Network Topology Planning your Wireless NetworkRoaming Topology the physical layout of a networkNetwork Layout LED Indicators Getting to Know the Wireless-G Notebook AdapterPower LinkSetup Wizard’s Welcome Screen Software Installation and ConfigurationSetup Wizard’s Wireless Mode Screen Installation ProcedurePassphrase or WEP key WEPWPA-PSK Setup Wizard’s Check Settings ScreenSetup Wizard’s Congratulations Screen Connecting the Adapter Hardware InstallationAccessing the Wlan Monitor Using the Wireless Network MonitorLink Information Wireless Network Status Wireless Network Statistics Site Information Site SurveyProfile Information ProfilesCreating a New Profile Creating a New Profile11 Ad-Hoc Mode Settings 12 Netowork Settings 14 WEP Setting for New Profile WPA Radius 15 WPA-PSK Settings17 WPA Radius Settings EAP-TTLS EAP-TLSEAP-PEAP EAP-MD5Leap Radius 24 Radius Settings26 EAP-TTLS Authentication 28 EAP-PEAP Authentication 30 Tkip Settings Common Problems and Solutions Appendix a TroubleshootingWireless-G Notebook Adapter does not work properly Frequently Asked Questions What is Spread Spectrum? What is ISM band?What is DSSS? What is FHSS? And what are their differences? What is WEP? Security Precautions Appendix B Wireless SecuritySecurity Threats Facing Wireless Networks Appendix B Wireless Security Wireless-G Notebook Adapter with SpeedBooster TCP/IP Appendix C Windows HelpAppendix D Glossary Wireless-G Notebook Adapter with SpeedBooster Wireless-G Notebook Adapter with SpeedBooster Wireless-G Notebook Adapter with SpeedBooster Wireless-G Notebook Adapter with SpeedBooster Wireless-G Notebook Adapter with SpeedBooster Wireless-G Notebook Adapter with SpeedBooster Appendix E Specifications Limited Warranty Appendix F Warranty InformationFCC Statement Appendix G Regulatory InformationIndustry Canada Canada EC Declaration of Conformity EuropeFrance Appendix H Contact Information
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