Linksys WRT54GP2A-AT manual What is ISM band?, What is Spread Spectrum?

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Wireless-G Broadband Router with 2 Phone Ports

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 (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.

Appendix A: Troubleshooting

60

Frequently Asked Questions

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Contents 802 GHz .11g Wireless- G How to Use this Guide Copyright and TrademarksWord definition Table of Contents Appendix B Wireless Security Signing up for AT&T CallVantagesm ServiceAppendix a Troubleshooting Appendix C Windows HelpList of Figures Back Panel18 Wireless Tab Advanced Wireless Settings Introduction WelcomeWhat’s in this Guide? Wireless-G Broadband Router with 2 Phone Ports Ssid your wireless network’s name Planning Your Wireless NetworkAd-Hoc versus Infrastructure Mode Network TopologyNetwork Layout Getting to Know the Router Phone2Wlan Connecting the Router Connecting the Router to Your Broadband ModemOverview Connecting One Router to Another Wired RouterConnect the Other Router Configuring the Router SetupWireless Security Access RestrictionsAdministration Applications & GamingInternet Setup How to Access the Web-based UtilitySetup Tab Basic Setup StatusStatic IP PPPoEOptional Settings Packet a unit of data sent over a networkNetwork Setup Network Address Server Settings DhcpRouter IP Time Setting Setup Tab Ddns DynDNS.orgTZO.com Setup Tab MAC Address Clone MAC CloneWireless Tab Basic Wireless Settings 10 Wireless Tab Basic Wireless SettingsWireless Tab Wireless Security WPA RadiusRadius Wireless Tab Wireless MAC Filter 15 Wireless Tab Wireless MAC FilterWireless Tab Advanced Wireless Settings Additional Filters Security Tab FirewallFirewall Block WAN RequestsSecurity Tab VPN VPN PassthroughAccess Restrictions Tab Internet Access Internet AccessTo create an Internet Access Policy 23 List of PCs Applications & Gaming Tab Port Range Forward Port Range ForwardPort Range Triggered Range Applications & Gaming Tab Port TriggerPort Trigger Forwarded RangeApplications & Gaming Tab UPnP Forward UPnP ForwardBroadband Router with 2 Phone Ports Applications & Gaming Tab DMZ DMZLocal Router Access Administration Tab ManagementRouter Password Remote Router AccessSnmp UPnPAdministration Tab Log LogTraceroute Test Administration Tab DiagnosticsPing Test Ping ParametersAdministration Tab Factory Defaults Factory DefaultsBackup and Restore Administration Tab Backup and RestoreAdministration Tab Reboot RebootRouter Information Configuration TypeStatus Tab Router InternetStatus Tab Local Network Local NetworkStatus Tab Wireless 39 Status Tab WirelessUser1 Status Auto Config StatusStatus Tab Voice User2 StatusSigning up for AT&T CallVantagesm Service InstructionsAppendix a Troubleshooting Common Problems and SolutionsFor Windows 98 and Millennium Need to set a static IP address on a PCFor Windows For Windows XPFor Windows 98 and Millennium Wireless-G Broadband Router with 2 Phone Ports Am not able to access the Router’s Web-based Utility Setup Need to set up a server behind my RouterApplication Start and End Protocol IP Address Enable TCPCan’t get the Internet game, server, or application to work For Microsoft Internet Explorer 5.0 or higher To start over, I need to set the Router to factory defaultMy DSL service’s PPPoE is always disconnecting For Netscape 4.7 or higherNeed to use port triggering Frequently Asked Questions Can I make calls if my Internet connection is down?Can I make calls while I’m browsing the Internet? Where is the Router installed on the network? Is IPSec Passthrough supported by the Router?Does the Router support IPX or AppleTalk? If all else fails in the installation, what can I do? How can I block corrupted FTP downloads?Will the Router function in a Macintosh environment? Is the Router cross-platform compatible? What is DMZ Hosting?What is the Ieee 802.11b standard? How many ports can be simultaneously forwarded?What Ieee 802.11g features are supported? What is the Ieee 802.11g standard?What Ieee 802.11b features are supported? What is ad-hoc mode?What is ISM band? What is Spread Spectrum?What is DSSS? What is FHSS? And what are their differences? What is a MAC Address? What is WEP?What is WPA? How do I reset the Router?Appendix B Wireless Security Security PrecautionsSecurity Threats Facing Wireless Networks Appendix B Wireless Security Wireless-G Broadband Router with 2 Phone Ports Appendix C Windows Help Shared ResourcesNetwork Neighborhood/My Network Places Windows 98 or Me Instructions Windows 2000 or XP InstructionsFor the Router’s Web-based Utility Figure D-3 MAC Address/Physical AddressAppendix E Glossary Wireless-G Broadband Router with 2 Phone Ports Wireless-G Broadband Router with 2 Phone Ports Wireless-G Broadband Router with 2 Phone Ports Wireless-G Broadband Router with 2 Phone Ports Wireless-G Broadband Router with 2 Phone Ports Wireless-G Broadband Router with 2 Phone Ports Model Appendix F SpecificationsButton Reset Cabling Type StandardsRinger Equivalence Number Dimensions 32 x 2.48 x H x DUnit Weight 19.29 oz .55 kg Power 12 V, 1 a Certifications Operating Temp 0ºC to 40ºC 32ºF to 104ºF Storage TempAppendix G Warranty Information Limited WarrantyAppendix H Regulatory Information FCC StatementSafety Notices After you log in, click Help. Then click Email AN Agent Appendix I Contact InformationLinksys Need to contact Linksys?
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