Planet WL-3560 User manual

IEEE802.11g Wireless PCMCIA Card
WL-3560
User Manual

2
Copyright
Copyright 2003 byPLANET TechnologyCorp. All rightsreserved. Nopart ofthis publi-
cation maybereproduced,transmitted, transcribed, stored in aretrievalsystem,or trans-
latedinto anylanguageorcomputer language,inanyformor byanymeans, electronic,
mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written per-
mission ofPLANET.
PLANET makes no representations or warranties, either expressed or implied,with respect
to the contentshereofandspecifically disclaimsanywarranties, merchantability or fitness for
anyparticular purpose.Anysoftware describedin this manual is sold or licensed "as is".
Should theprogramsprovedefectivefollowingtheir purchase, thebuyer (andnot PLANET,
itsdistributor,or itsdealer)assumes the entire cost of all necessaryservicing,repair,and
anyincidental or consequentialdamages resulting fromanydefect in thesoftware. Further,
PLANET reserves the right to revise this publication andto makechanges fromtimeto time
in the contents hereof without obligationto notifyanyperson ofsuch revision or changes.
All brand andproduct names mentionedin this manual are trademarksand/or registered
trademarks oftheir respective holders.
Federal Communication Commission Interference Statement
This equipment has beentested and found to complywith the limitsfor aClass Bdigitalde-
vice,pursuant toPart 15 of FCC Rules. These limitsare designed toprovide reasonable
protection against harmful interference in aresidential installation. This equipment generates,
uses, andcanradiate radio frequencyenergyand, ifnot installed andusedin accordance
with the instructions, maycause harmful interferenceto radio communications. However,
there is noguaranteethatinterference will notoccur inaparticular installation. Ifthis
equipment does cause harmful interference to radio or television reception, which can be
determined byturning theequipment offand on, the user is encouragedto tryto correct the
interference byoneor more ofthe followingmeasures:
1. Reorient or relocate the receiving antenna.
2. Increase the separation between the equipment and receiver.
3. Connect the equipment intoan outlet onacircuit different fromthat to whichthere-
ceiver is connected.
4. Consult the dealer or an experienced radio technician for help.
FCC Caution
Toassure continued compliance. (example-use onlyshieldedinterface cables when con-
nectingtocomputer or peripheraldevices). Anychanges or modifications not expresslyap-
proved bythe partyresponsible for compliance could void the user s authorityto operate the
equipment.

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This device complies with Part 15 oftheFCC Rules. Operation is subject to the Following
two conditions: ( 1 ) This device maynot causeharmfulinterference, and ( 2 ) this Device
must accept anyinterference received, includinginterference that maycause undesired
operation.
Federal Communication Commission (FCC) Radiation Exposure State-
ment
This equipment complies with FCCradiation exposure set forth for an uncontrolled envi-
ronment. In order to avoid the possibilityofexceeding the FCC radio frequencyexposure
limits, human proximityto the antenna shall not be less than 20 cm(8 inches) during normal
operation.
R&TTE Compliance Statement
This equipment complies with all the requirements ofDIRECTIVE 1999/5/CE OF THE
EUROPEAN PARLIAMENT ANDTHE COUNCILOF 9 March 1999 on radioequipment and
telecommunication terminal Equipment and the mutual recognition oftheir conformity
(R&TTE)
The R&TTE Directive repeals and replaces in the directive98/13/EEC (Telecommunications
Terminal Equipment and Satellite Earth Station Equipment) As ofApril 8,2000.
Safety
This equipment is designedwith the utmost care for the safety ofthose who install and use it.
However,special attention must be paidto thedangersofelectric shockandstatic electricity
when working with electrical equipment. All guidelines ofthis and ofthe computer manu-
facture must therefore be allowed atall times to ensurethe safe use ofthe equipment.
EU Countries Not Intended for Use
The ETSI version ofthis device is intendedfor home and office use inAustria Belgium,
Denmark, Finland, France(with Frequencychannel restrictions). Germany, Greece, Ireland,
Italy,Luxembourg .The Netherlands, Portugal, Spain, Sweden andUnitedKingdom.
The ETSI version ofthis device is also authorized for use in EFTA member states Iceland,
Liechtenstein, Norwayand Switzerland.
Potential restrictive use
France: Onlychannels 10,11,12 and13
Revision
User s Manual for PLANET IEEE802.11g Wireless PCMCIACard
Model: WL-3560
Rev:1.0(July,2003)
Part No. EM-WL3560V1

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Manual Contents
CHAPTER 1 INTRODUCTION...............................................1
1.1 FEATURES ...............................................................................................1
1.2 APPLICATIONS..........................................................................................2
1.3 SPECIFICATION.........................................................................................4
1.4 PACKAGE CONTENTS................................................................................4
1.5 MINIMUM SYSTEM REQUIREMENTS ............................................................4
1.6 SAFETYPRECAUTION........................................................................5
1.7 INSTALLATION CONSIDERATIONS ................................................................5
CHAPTER 2 INSTALLATION PROCEDURE..............6
2.1 CONFIGURATION UTILITY INSTALLATION......................................................6
2.2WINDOWS 98/ME/2000/XP/SERVER 2003 DRIVER INSTALLATION................8
CHAPTER 3 CONFIGURATION UTILITY....................10
3.1 LINK INFO ..............................................................................................10
3.2 CONFIGURATION......................................................................................11
3.3 ADVANCED.............................................................................................12
3.4 SITE SURVEY.........................................................................................13
3.5ABOUT...................................................................................................13
APPENDIX...........................................................................................14

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Chapter 1 Introduction
The WL-3560 is an IEEE 802.11g Wireless PCMCIAcard that can operate in eitherAd-Hoc
mode (Pointto Point/Pointto Multipoint without anAccess Point) or Infrastructure mode (Point
to Point/Point to Multipoint with anAccess Point). Withalmost 5times the datarate oftradi-
tional 802.11b products, it is suitable for multimedia applications which require greater band-
width.It operates in the2.4GHzunlicensedISM band, and is compliant with both 802.11b and
802.11g standards. This dual-standard support allowsfor greater flexibilityofdeployment and
use.
The WL-3560 supportsboth64/128-bit WEP(Wired EquivalentPrivacy)andWi-Fi Protected
Access (WPA) for securing wireless network connections. The driver and utilitysupportsmost
popular operating systems: Windows98SE/ME/2000/XP/Server 2003. With advanced features
and highperformance capability,the WL-8310 is anexcellent choice for constructingawide
range ofwireless solutions.
1.1 Features
l Fullycompliant with wireless LAN IEEE 802.11g and802.11b standards
l Wireless connectionwithout the difficultyand cost ofcabling
l Highperformance with datarate up to 54 Mbps for 802.11g and 11Mbps for 802.11b
l Based on 2.4GHz Direct Sequence Spread Spectrum(DSSS) Technology
l Supports64/128-bitWEP(Wired EquivalentPrivacy)and Wi-Fi ProtectedAccess
(WPA)
l SupportsAd-Hoc (Peer to Peer) communication andInfrastructure mode withan Ac-
cess Point
l Seamless integration with IEEE 802.3 LAN throughanyIEEE 802.11bor 802.11g
compliant Access Point
l Supportsmost popular operatingsystemsincluding Windows98/Me/2000/XP/Server
2003
l LowInterference and HighSusceptibilityGuaranteeReliable Performance
l Supports Power Save mode
l Plug-and-Playinstallation

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1.2 Applications
1.2.1Infrastructure
The WL-3560 provides access to awired LAN for wireless workstations. An integrated
wireless and wiredLAN is called an Infrastructure configuration.Agroup ofWL-3560 PC
users andanAccess Point compose a Basic ServiceSet (BSS).Each WL-3560 PC ina
BSS can talkto anycomputer in the wiredLAN infrastructure via theAccess Point.
An Infrastructure configuration extends the accessibilityof aWL-3560 equippedPC to a
wired LAN, and doubles theeffective wireless transmission range for 2WL-3560PCs.
Since theAccess Point is able toforwarddata within its BSS, the effective transmission
range in an infrastructure LAN is doubled.
The use ofaunique IDinaBSS is essential. All WL-3560equippedPCs configured
without roaming options in an independent BSS must be configuredwithaBSS IDcor-
respondingtotheWL-3560 usedintheBSS. Check your WL-3560 for itsBSS ID or use
the Site Surveyfunction on Configuration Utilityprogramto determine the BSS ID.
The Infrastructure Wireless LANconfigurationis appropriatefor enterprise-scalewire-
less access to a central database, or as a wireless applicationfor mobileusers.
Infrastructure mode alsosupportsroamingcapabilities for mobileusers. Morethanone
BSS canbe configuredas an Extended Service Set(ESS). The continuous networkal-
lowsusers to roamfreelywithin an ESS.All WL-3560 PCs or other IEEE 802.11b and
802.11g compliantwireless adapters within one ESS must be configured with thesame
ESS ID anduse the same radio channel.
Before enabling anESS with roaming capability,choosing afeasible radio channel and
optimumAccess Pointpositionis recommended. Proper Access Point positioning com-
bined with a clear radio signal will greatlyenhance performance.
1.2.2Ad-Hoc
AnAd-Hoc wireless LAN is agroup ofcomputers, each equipped withoneWL-3560
adapter or other wireless adapters, connected as anindependent wireless LAN. Com-
puters inaspecific Ad-Hoc wireless LANmust beconfiguredtosharethesameradio
channel.

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Ad-Hoc wireless LANconfigurations areappropriatefor branch leveldepartmentsor
SOHO operations.
1.2.3General Application
WL-3560 offers a fast, reliable,cost-effective solution for wireless client access to the
networkin applications like these:
1. Remote access to corporate network information
E-mail, file transfer and terminal emulation.
2. Difficult-to-wire environments
Historical or old buildings, asbestos installations, and open area where wiring is diffi-
cult toemploy.
3. Frequentlychanging environments
Retailers, manufacturers and banks who frequentlyrearrange the workplace and
changelocation.
4. Temporary LANs for specialprojects or peak time
Trade shows, exhibitions and construction sites need temporarysetup for a short time
period. Retailers, airlineand shipping companies need additionalworkstations for a
peakperiod. Auditors require workgroups at customer sites.
5. Access to database for mobile workers
Doctors, nurses, retailers, white-collar workers need access to database while being
mobile in the hospital, retail store or office campus.
6. SOHO (Small Office and Home Office) users
SOHO users need easyand quickinstallation ofa small computer network.
7. High securityconnection
The wireless securitynetworkinstalls quicklyand provides the flexibilityto reconfigure
easily.

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1.3 Specification
Product IEEE802.11g Wireless PCMCIACard
Model NameWL-3560
Attachment Interface PC CardBus 32-bit compliant
LED Indicators Two Link/Act
Operating Frequency/
Channel 2.412~2.462GHz (FCC, USA & Canada) /11 Channels 2.412~2.4835GHz (TELEC,Japan) / 14 Channels
2.412~2.472GHz (ETSI, Europe) / 13 Channels
RF Modulation Direct Sequence Spread Spectrum(DSSS) Technology
(OFDM, CCK, QPSK,BPSK)
RF OutputPower 16dBm(typical)
Sensitivity 802.11g:-66dBm@ PER<8%, 54Mbps
802.11b:-82dBm@ PER<8%, 11Mbps
Data Rate 802.11g: 54, 48,36, 24, 18, 12, 9, 6Mbps with auto-
rate fall
back
802.11b:11,5.5, 2, 1 Mbpswithauto-rate fall back
Media Access ProtocolCSMA/CA+ ACK
Antenna Built-in patch antenna
Working Mode Ad-Hoc, Infrastructure
Dimension (mm) 119 x 54 x 12mm
Humidity 0-95%, non-condensing (Operating andstorage)
Temperature 0 –55 degreeC (Operating), -10~70 degree C (Storage)
Compatibility Windows 98SE/ME/2000/XP/Server 2003
Management Utilityor Windows XP built-in management interface
Electromagnetic Compatibil-
ity FCC Part 15 class B, CEMark, ETS 300 328
1.4 Package Contents
Before installation,please checkthe items of your package. The package should include the
following items:
WL-3560 x 1
QuickInstallationGuide x 1
Drivers and User sManual CD x 1
If any of the above itemsare missing,contact your supplier as soon as possible.
1.5 MinimumSystem Requirements
Before installation,please checkthe followingrequirementswithyour equipment.
• Operating System:Windows 98/Me/2000/XP/Server 2003
• PC with CD-ROM driver
• One vacant PCMCIA slot

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1.6 SAFETY PRECAUTION
Onlyuse the accessories attached with the device package. Otherwise, the device maynot
function. If you miss or damage the accessories, please contact your local dealer.
1.7 Installation Considerations
l Please keep the number ofwalls andceilings betweenthe Access Point and clients as
less as possible.Each wall or ceiling can reduce your wireless cover range form3-90
feet. PositionyourAccess points, Residential Gateways,and computers so that the
number ofwalls or ceilings is minimized.
l Building materials make a difference –Asolid metal door or aluminumstuds mayhave a
negative effect on range. Tryto positionAccess Points,and computers withwireless
adapters so that the signalpasses through drywall or open doorways and not otherma-
terials.
l Keep thewireless product awayformelectrical devices or appliances at least 3-6 foot,
which maygenerate extreme RF noise.

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Chapter 2 Installation Procedure
Before youproceed withthe installation, itis necessarythatyou haveenough information
aboutthe Wireless PCMCIACard. Use the Proceduredescribed belowto install thecard under
Windows 98/Me/2000/XP/Server 2003.
Note: If you ever installthe other WirelessCard before, please uninstallthe existed
driverand utility first. If this is the first time to install this device, please refer to the
following steps to complete the installation.
2.1 Configuration UtilityInstallation
Please install the configurationutilitybefore insert WL-3560 intothePCMCIAslot ofthe
computer.
1. Insert the CD-ROM into the CD-ROM drive to initiate the autorun program.Once
completed a menu screen will appear as follows.
2. Clickon “ConfigurationUtility”hyper linkin WL-3560 fieldto initiatetheinstallation. If
the above screen is not shown, youcan clickthe “Start”button and choose “Run”.
When the box appears, enter “E:\Utility\WL-3560\setup.exe”(Suppose “E”is your
CD-ROM drive). Youwill seethe dialog box as the picture. Please click “Next”to con-
tinue.

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3. Youcan click “Browse”to specifythe Destination Folder that youwant toinstall the
configuration utility. Or you can keep the default settingand click ”Next”to continue.
4. Select the programfolder you wantto install this utilityto. Or you cankeep the default
setting and click ”Next”to continue.
5. Click “Finish”to completethe installationprocedures.

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2.2 Windows 98/ME/2000/XP/Server 2003 Driver Installation
Note: The following installation operates under Windows XP. Procedureswill be
similar to other operatingsystem.
1. Insert WL-3560 toa vacant PCMCIAslot and turnon the computer.
2. The “Found NewHardware Wizard”screenwill appear.Please select “Install froma
specific location (Advanced)”option, and click “Next”to continue.
3. Insert Driver andUser sManualCDintoCD-ROMdrive.Select “Include this location in
the search”and then click “Browse”to find out WL-3560 driver location to install driver.(Assume
"E" is your CD-ROM drive, you can find out WL-3560 driver in E:\Drivers\WL-8310). Please click
“Next”to continue.

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4. Adialogue box will pop up. Click “ContinueAnyway”tocontinue.
5. Click “Finish”to completethe installation.

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Chapter 3 Configuration Utility
The Configuration Utilityis a powerful application that helpsyou to configure the WL-3560 and
monitor thestatus ofthe communication process. Bydoubleclickthe icon on the system
tray, the dialogbox as belowappears.
This utilitycan be used to modifytheconfiguration parameters when the device is active.
Following details the configuration options.
3.1 Link Info
This screen contains current linkinformation ofWL-3560.
Status: Showsthe BSSID associated with,which can be used to identifythewireless
network.
SSID: Showscurrent SSID,which must bethesamefor the wireless clientandAPin
order to establish the communication.
Frequency: Shows the current frequencyused for wireless network.
Wireless Mode: Shows thecurrent wireless mode used for wireless communication.
Encryption: Showsthe current encryption mode usedfor wireless network.
TxRate: Shows the currentdata rate used for transmitting.
Channel: Shows the current channel for communication.
Link Quality: ShowsthelinkqualityofWL-3560 withthe Access Pointwhenoperating
in Infrastructure mode.
SignalStrength: Showsthe wireless signal strengthoftheconnectionbetween the
WL-3560 andtheAccess Point.
DataRate: Showsthestatistics ofdatatransfer,and the calculation is basedonthe
number ofpackets transmitted and received.

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3.2 Configuration
In this screen, youcan configure the wireless settingsofWL-3560.After configuration,
please press ”Apply”to save settings or “Cancel”to setagain.
u SSID: The SSID must be identical for each clients andnodes in the wireless network.
u Wireless Mode: Clickpull-downbutton and select the workmode below.
Ø Ad-Hoc: This mode indicates the peer-to-peer operation.All communication is
donefromclient to client withouttheuse ofanAccess Point.
Ø Infrastructure: This operation mode requires the presence ofan Access Point. All
communicationis donevia the Access Point.
u AdHoc Band: There are two bands available for selection
Ø 11B: Allowsuser to set the 802.11b standard wireless network.
Ø 11G: Allows user to set the 802.11g standard wireless network.
u Channel: Shows the number ofthe radio channel used for the networking.
u Tx Rate (11B/G): ShowstheData Transfer Rate. IfAuto Mode is selected, the device
will choose the best transfer rate automatically.
u Power Mode: ShowsPower Management modes. There aretwo optionalselections for
this mode.
Ø Continuous Access Mode: WL-3560 will always set in active mode.
Ø Maximum Power Save: WL-3560will enter power saving mode when it is idle.
Ø Power Save: WL-3560 consumes the moderate level ofpower.
u Preamble: There is twooptions canbeselected:Short&LongPreamble, LongPream-
ble. Preamble is asequenceof bitstransmitted at 1Mbpsthat allowsthe PHYcircuitryto
reach steady-statedemodulationand synchronizationofbitclockand framestart. Two
different preambles and headers are defined: the mandatorysupportedLong Preamble
and header,whichinteroperate with the 1Mbit/s and2Mbit/s DSSS specification (as
described in IEEE 802.11), and anoptionalShort Preamble and header (as described in

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IEEE 802.11b). At thereceiver,thePreamble and header are processed to aid in de-
modulationand deliveryofthe PSDU. The Short Preamble and header maybe used to
minimize overheadand,thus, maximizethenetworkdatathroughput.However,the Short
Preamble is supportedonlyfromthe IEEE 802.11b(High-Rate) standardand not from
the originalIEEE 802.11. That means that stations using Short-Preamble cannot com-
municate with stations implementing the originalversion ofthe protocol.
3.3 Advanced
Additional securitycanbe achievedbyusing the WEP (Wired Equivalent Privacy)encryption.
WEP encryptseach frametransmitted fromthe radiousingoneofthe keysentered fromthis
panel.
u Encryption: Enable or disable WEPencryption.
u Auth. Mode:
Ø Open Authentication: With this setting, thestationinthe WLAN canreceives and
transmits data fromAccess Point (null authentication).
Ø Shared Authentication: With this setting, allowscommunication only with other devices
with identical WEP settings.
Ø Auto Switch: With this setting, stations can communicatewith the Access Point either with
or without dataencryption. Itwill detect the AP that it connected is using which Authentication
mode and use the same mode to communicate.
u WEPKey options:
Ø Default Key: There are 4 keys availablefor theWEP function. Pleaseselect oneof
themfor WEP to operate.
Ø Network Key: You candefine the WEP(Wired Equivalent Privacy)Keyvalues by
yourself.
Ø KeyLength Pleaseselect which WEPkeymodeyouwanttouse. There are

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three modes, eachmode has twokind ofkeylength and that is decideon the Key
Format you selected.64bit (5ASCII / 10HEX.), 128bit (13ASCII / 26HEX) or 256bit
(29ASCII /58HEX).
u KeyFormat You canselect WEPkeyformat to HEX (Hexadecimal code,0-9,A-F) or
ASCII (American Standard Code for Information Interchange, 0-9, a-z, A-Z).
3.4 Site Survey
This screen showsthe APs or Adapters which available fro WL-3560 to connect. Ifyou con-
figure theSSID ofWL-3560 as “Any”, it will showthe available APs and Adaptersat thesame
time.
Click “Refresh “tocollect the BSSIDand Channelinformation ofall thewireless devices
aroundyou.
Ifyouwish to connect toanydevice onthe “AvailableNetwork”list, select the device onthe
list andclick “Connect”,then WL-3560 will connect to the selected device andcreate aprofile
for the selected device automatically.
You can configure profile with those buttons:
Ø Add: Add a newprofile.
Ø Remove: Delete the profile you selected.
Ø Properties: Modifythe profile you selected.
After press Add or Properties,the dialogbox will appears for configuringprofile. You canrefer
to above toknowhowto configure the setting for your need.
3.5 About
It shows the current Driver, Firmware and Utility version.

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Appendix
This section provides sometechnologyQ&A. Read the descriptionbelowto know more about
the wireless network.
ü What is the difference between 54Mbpsand 11Mbpswireless products? What’sthe
benefit of 54Mbps Wireless Access Point?
The 54Mbpsis made possible bythe newmodulationmethod called OFDM, which is
different fromthe currentCCK modulationmethod for 11Mbps. The 54Mbpswireless
productsalsooperatein the2.4GHzISMbandandtheyare backward compatible with
11Mbpswireless products.
ü What is ISMband?
The FCC and their counterpartsoutside ofthe U.S. have set asidebandwidth forunli-
censed usein the ISM (Industrial,Scientific and Medical) band. The 2.4GHzunlicensed
ISM band is available worldwide, which presentstheopportunity for the globalmarket of
802.11b and 802.11ghigh speed wireless products.
ü What is Ad-Hoc?
An Ad-Hoc integrated wireless LANisagroup ofcomputers, each withaWLAN adapter,
Connected as anindependentwireless LAN. Ad-Hocwireless LANis applicable at a
departmental scale for a branch or SOHO operation.
ü What is Infrastructure?
An integratedwireless andwiredLANiscalledanInfrastructure configuration.Infra-
structure is applicable toenterprise scale for wirelessaccess to centraldatabase, or
wireless application for mobile workers.
ü What is BSS ID?
Aspecific Ad-Hoc LAN is called aBasic Service Set(BSS). Computers in aBSS must
be configured withthesame BSS ID.
ü What is Roaming?
Roaming is theabilityofportable computers, e.g., Packet PC and notebook,to have
consistentand continuous datatransmission/receptionthroughoutanareacovered by
more than oneWireless Access Point. In order toachieveseamless connectivity,all
the wireless clientsandAccess Pointsmust be set touse the sameSSID. When a
user walked out ofthecoverage area ofoneAP intoanother,the wireless client network
device will automaticallyreestablish connection withthe newAP.
ü What is a MACAddress?
The Media Access Control(MAC) address is aunique number assigned bythemanu-
facturer to anyEthernet networking devices, e.g. anetworkadapter,thatallowsthe
networkto identifyit at the hardware level. Unlike IPaddresses, which can be

15
changedor dynamicallyassignedbythe network,the MACaddress ofanetworking
device is permanent.
ü What is WEP?
Wired EquivalentPrivacy(WEP) is atypeofdataencryptionmechanismdescribed in
the IEEE 802.11 standard.
ü Could Iimplement the driver/utilityinstallations onanother operating system, e.g.
Windows98SE, 2000andME? Are there anydifferences of driver/utilityinstalla-
tions among these different operating systems?
Yes,you can. All theinstallationmentioned in this user s manual could be implemented
on Windows 98SE/ME/200/XPand there will be no difference.
ü Can Wireless productssupport printer sharing?
Wireless productsperformthe samefunction as LAN products. Therefore, Wireless
productscanworkwithNetware,WindowsNT/2000/XP,or other LAN operatingsys-
tems to support printer or file sharing.
ü What is DSSS What is FHSS And what are theirdifferences?
Frequency-hopping-spread-spectrum(FHSS) uses anarrowband carrier that changes
frequencyin apattern that is knowntoboth transmitter and receiver.Properlysynchro-
nized,thenet effect is to maintain asingle logical channel. Toan unintendedreceiver,
FHSS appears to be short-duration impulse noise. Direct-sequence spread-spectrum
(DSSS) generates aredundant bit pattern for each bit to be transmitted. This bit pattern
is calledachip (or chippingcode). The longer thechip, the greater the probabilitythat
the original data canberecovered.Evenifoneormore bitsinthechiparedamaged
duringtransmission, statistical techniques embeddedin theradiocanrecover the
originaldata without-theneed for retransmission. Toan unintended receiver,DSSS
appears as lowpower widebandnoise and is rejected(ignored) bymost narrowband
receivers.
ü What is Spread Spectrum?
SpreadSpectrumtechnology isawidebandradiofrequency technique developed by the
militaryfor usein reliable,secure, mission-criticalcommunication systems. It is de-
signedtotradeoffbandwidth efficiencyfor reliability,integrity,and security.Inother
words, more bandwidthis consumed than in the caseofnarrowband transmission, but
the trade offproduces asignalthat is, in effect, louder and thus easier todetect, pro-
videdthatthereceiver knowstheparameters ofthespread-spectrumsignal being
broadcast. Ifareceiver is not tuned to theright frequency,aspread –spectrumsignal
lookslikebackground noise. There are twomain alternatives, Direct Sequence Spread
Spectrum(DSSS) andFrequencyHopping Spread Spectrum(FHSS).