Mitac Digital Technology LBU02 User Manual

LBU02

User’s Manual

Revision: R00

(December 2001)

TRADEMARKS

All brand and product names are trademarks or registered trademarks of their
respective companies.

NOTE

Information in this manual is subject to change without notice.

0 Table of Contents

Regulation s Information.........................................................iii

Safety Precautions.................................................................3

1 Introduction ..........................................................................5

1.1 Product Description.................................................................1

1.2 Product View ........................................................................... 3

2 Setting Up ............................................................................. 5

2.1 System Requirements............................................................. 5

2.2 Installing the Driver and Utility.................................................5

For Windows 98/2000/Me/XP ................................................ 5

For Linux................................................................................8

2.3 Connecting the WLAN USB Dongle ........................................8

2.4 Site Selection..........................................................................9

3 Using Configuration & Monitor Application Utility.......... 11

3.1 Getting Started......................................................................11

3.2 Monitor.................................................................................. 12

3.3 Statistics................................................................................14

3.4 Site Survey............................................................................15

3.5 Encryption............................................................................. 16

3.6 Advanced..............................................................................17

4 Troubleshooting.................................................................19

4.1 Preliminary Checklist............................................................. 19

4.2 Installation Problem............................................................... 19

4.3 Configuration Problem...........................................................20

4.4 Access Point Problem (Infrastructure Mode).........................20

4.5 Communication Problem.......................................................20

4.6 LAN Problem......................................................................... 21

1

4.7 Software Problem..................................................................21

A Appendix.............................................................................23

A.1 Specifications........................................................................23

A.2 Uninstalling the Utility and Driver...........................................24

Configuration & Monitor Application Utility............................24

WLAN USB Dongle..............................................................24

Glossary.................................................................................... 25

Regulations Information

Federal Communications Commission Interference Statement

This equipment has been tested and found to comply with the limits for a Class B digital device
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference in a residential installation. This equipment generates, uses, and can
radiate radio frequency energy and , if not installed and used in accordance with the instructions,
may cause harmful interference to radio communications. However, t here is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment
off and on, the user is encouraged to try to correct the interference by one or more of the following
measures:

 Reorient or relocate the receiving antenna.
 Increase the separation between the equipment and receiver.
 Connect the equipment into an outlet on a circuit different from that to which the receiver is

connected.

 Consult the dealer or an experienced radio/TV technician for help.

FCC Caution:

To ensure continued compli ance, use only shielded interface cables when connecting to the
computer or peripheral devices. Any changes or modifications not expressly approved by the
party responsible for compliance could void the user’s authority to operate this equipment.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions:

1. This device may not cau se harmful interference, and

2. This device must accept any interference received, includin g interference that may cause

undesired operation.

FCC Radiation Exposure Statement:

 This equipment complies with FCC radiation exposure limits set forth for an uncontrolled

environment. This equipment should be installed and operated with a minimum distance of
20 cm between the radiator and your body.

 This transmitter must not be co-locate d or o pera te d i n co nju nctio n with any other antenna or

transmitter.

3

Safety Precautions

 Be sure to read and follow all warning notices and instructions.
 In order to extend th e life of the device it is advised to sto re it in a p rotectiv e

casing whenever carrying the computing device on travel and not ope rat ing
the device.

 Never use abrasive materials or rinse the device with liquids.
 At all times, it will be the responsibility of the end-user to ensure that an

outdoor antenna installation complies with local radio regulations.

 Do not service the product by yourself. Refer all servicing to qualified

service personnel.

Exposure to Radio Frequency Signal

Your wireless device is a low power radio transmitter and receiver. When it is
ON, it receives and also sends out Radio Frequency (RF) signals. International
agencies have set standards and recommendations for the protection of public
exposure to RF electromagnetic energy. The design of your wireless device
complies with these standards when used normally. In order to limit Radio
Frequency (RF) exposure, the following rules should be applied:

 While installing the antenna in the location, please do not turn on power of

the device.

 While the device is working (linking), please do not touch or move the

antenna. Contact with the antenna affects link quality and may cause the
wireless device to operate at a higher power level than otherwise needed.

 Do not operate a portable transmitter near unshielded blasting caps or in an

explosive environment unless it is a type especially qualified for such use.

1 Introduction

This chapter introduces the features and functions of the product.

1.1 Product Description

Congratulations on purchasing this USB (Universal Serial Bus) Dongle
Wireless Local Area Network (WLAN) device.

Your WLAN USB Dongle’s 11 Mbps data rate provides an equiv alent E the rne t
speed to access corporate networks or the Internet in a wireless environment.
When installed, the WLAN USB Dongle is able to communicate with any

802.11b-compliant product, allowing you to work anywhere in the coverage
area, enjoying its convenience and mobility.

Your WLAN USB Dongle features:

 IEEE 802.11b and Wi-Fi-compliant 11 Mbps WLAN access solution
 Direct Sequence Spread Spectrum (DSSS) standard
 Wired Equivalent Privacy (WEP) 128-bit data encryption
 Frequency range at 2.4 GHz ISM band
 Automatic data rate selection at 11 Mbps, 5.5 Mbps, 2 Mbps, and 1 Mbps

(automatic data rate fallback under noisy environment)

 USB interface Plug-and-Play
 High sensitivity and output power

5

Typical applications include:

 IEEE 802.11b-compliant WLAN radio
 Notebook computer wireless modem
 Point-to-Point data
 Wireless home networking
 Small Office Home Office (SOHO) wireless application

1.2 Product View

Ref Component Description

Wireless Connection



Indicator

Power Indicator



Integrated Antenna



USB Port



Glows green when the WLAN USB Dongle ha s
successfully linked with an Access Point
(Infrastructure mode) or with another wireless station
(Ad-Hoc mode).

Glows red when the WLAN USB Dongle is connected
to your computer and is deriving power from it.

Allows the WLAN USB Dongle to receive and
transmit wireless data.

Use a USB cord to connect the WLAN USB Dongle to
a computer.

7

2 Setting Up

This chapter tells you how to setup the device for use.

2.1 System Requirements

To use the device, you need:

 Operating system: Windows 98, Windows Me, Windows 2000, Windows

XP, or Linux 2.2.x

 Available USB port on your computing device
 CD-ROM Drive

2.2 Installing the Driver and Utility

For Windows 98/2000/Me/XP

CAUTION: Do not connect your WLAN USB Dongle to the computer at this stage until you
are required to do so.

NOTE: When using Windows 2000 and before proceeding, make sure you have logged on
as “Administrator.”

1. Insert the driver CD into the CD-ROM drive and double-click the file

SETUP.EXE under the Windows/Setup directory.

2. Follow the onscreen instructions to continue.

3. When the next screen appears, select the option “Application & USB

Drivers” to install the utility (Conf ig uration and Moni to r Applica ti on) and
the WLAN USB Dongle driver.

9

NOTE: If the WLAN USB Dongle driver have been previously installed and have not been
uninstalled prior to this latest installation, the new driver will overwrite the old one without
prompting you.

4. After you have confirmed the driv er’ s “Des tinat ion Lo ca tion ” as well as the

“Program Folders,” choose the mode of operation whether Ad-Hoc or
Infrastructure on the Operating Mode Dialog window.

 Ad-Hoc Mode

In Ad-Hoc mode the wireless stations can communicate directly with
each other.

When selecting the Ad-Hoc mode you need to specify the ESSID and
the Channel parameters.

– ESSID: All stations participating in the Ad-Hoc network should

have the same ESSID.

– Channel: Select the 14 channels available for use.

 Infrastructure Mode

In Infrastructure mode the use of an Access Poin t (AP) is ne cessary for
wireless stations to communicate with each other.

When selecting the Infrastructure mode you need to specify the
ESSID.

– ESSID: Specify the ESSID of the AP to which the wireless station

will be associated with.

NOTE: You can still change the Operating Mode afterwards using the Configuration &
Monitor Application utility.

11

5. After you have made your selection, click Next and a window listing your

installation setting appears. If the settings are correct, click Next to
continue. In case you made a m istake, click Back to make the co rrection and
follow the onscreen instructions to exit the installation.

NOTE: For Windows 2000, select Yes when the “Digital Signature Not Found” window
appears.

6. Re-boot your system after completing the installation.

NOTE: To uninstall the driver and utility, refer to the section “Uninstalling the Driver and
Utility” on the Appendix.

7. Upon re-booting your system, the Configuration & Monitor Application

utility icon should appear on your Window’s system tray.

For Linux

Module Parameters

In order to reconfigure th e WLAN USB Dongle, use one of the applicat ions that
comes with the driver:

 fvnet (command line utility) or
 xvnet (graphical interface for the X windows)

For more information on using the fvnet and xvnet applications, refer to the
relevant Linux system manual pages (man xvnet or man fvnet).

NOTE: If nothing happens the first time you plug in your WLAN USB Dongle,
then run # insmod vnetusba.

2.3 Connecting the WLAN USB Dongle

NOTE: Make sure that the WLAN USB Dongle’s driver as well as the Configuration &
Monitor Application utility has been properly installed (see previous section).

Connect one end of the included USB cord to the WLAN USB Dongle’s USB
port and the other end to the USB port of your computer.

NOTE: If you have never installed the driver of the USB port of your system, then Windows
would automatically detect the new hardware and may prompt you to install it. Have the
Windows installation CD ready (in case you are prompted for it) and follow the onscreen
instructions to install the driver.

Your WLAN USB Dongle should start searching for wireless signals from an
AP (Infrastructure mode) or another wireless station (Ad-Hoc mode).

2.4 Site Selection

The following are the tested typical outdoor operating range:

 250 M at 11 Mbps (high speed)
 350 M at 5.5 Mbps (medium speed)
 400 M at 2 Mbps (standard speed)
 500 M at 1 Mbps (low speed)

The range of the wireless signal is related to the Transmit Rate of the wireless
communication (Tx Rate on the Monitor utility of the Configuration &
Monitor Application utility). Communications at lower transmit range may
travel larger distance s.

13

NOTE: The range values listed above are typical distances measured. These values may
provide a rule of thumb and may vary according to the actual radio conditions at the
location where the WLAN USB Dongle will be installed.

 The range of your wireless devices can be affected when the antennas are placed near

metal surfaces and solid high-density materials.

 Range is also impacted due to “obstacles” in the signal path of the radio that may either

absorb or reflect the radio signal.

If you intend to use the WLAN USB Dongle as part of an outdoor antenna
installation, the range of the outdoor antenna installation will be related to
clearance of the radio signal path.

The typical conditions when used indoors in “office environments” can be
described as follows:

 In Open Office environments, ante nnas can “see” ea ch other, i.e., t here are

no physical obstructions between them . This desc ribes the ide al indoor
antenna installation.

 In Semi-open Office environments, workspace is divided by shoulder-

height, hollow wall elements; antenna are at desktop lev el. Th is desc ribes
the typical indoor antenna installa t ion.

 In Closed Office environments, workspace is separated by floor-to-floor

ceiling brick walls. This type o f indoor an tenna insta llation is no t applica ble
to your WLAN USB Dongle.

3 Using the Configuration &

Monitor Application Utility

3.1 Getting Started

In special circumstances, you may need to change configuration settings
depending on how you would like to manage your wireless network. The
Configuration & Monitor App licat ion utility enables y ou to m ake config uration
changes and perform user-level diagnostics on your WLAN USB Dongle as
well as monitor the status of communication.

To use the Configuration & Monitor Application utility:

1. Make sure that the Configuration & Monitor Application utility has been

installed properly (see Chapter 2).

2. The Configuration & Monitor Application utility appears as an icon on the

Windows’ system tray. Double-click on this icon.

NOTES:

 When the station is in Infrastructure mode and not associated with an AP, color of the

icon is red.

 When the station is in Infrastructure mode and associated with an AP, color of icon is

blue.

 When the station is in Ad-Hoc mode, color of icon is always blue.
 When the station is in Ad-Hoc mode and the WLAN USB Dongle is resetting and

initializing, color of icon is red.

3. When the Configuration & Monitor Application utility appears onscreen,

make sure that “USB Dongle” is selected on the very top of the window.

15

3.2 Monitor

The following configuration parameters are shown:

 Operating Mode

Allows you to choose between Ad-Hoc or Infrastructure mode. In Ad-Hoc
mode the wireless stations can communicate directly with each other. In
Infrastructure mode the use of an Access Point (AP) is necessary for
wireless stations to communicate with each other.

 Channel

This item is available only if Ad-Hoc mode was selected in the previous
field. Select the 14 channels available for use.

 SSID

When using the wireless station in an Ad-Hoc mode then all participating
stations should have the same SSID. When using the wireless station in an
Infrastructure mode the SSID must be the same as the SSID of the AP it is
associated with.

 TxRate

Your WLAN USB Dongle provides various transmission (data) ra te options
for you to select. In most networking scenarios, the option Auto will prove
the most efficient. This setting allows your WLAN USB Dongle to operate
at the maximum transmission rate. When the communication quality drops
below a certain level, the WLAN USB Dongle will automatically switch to
a lower transmission rate. Transmiss ion at lower data speeds are usual ly
more reliable. However, when the communication quality improves again,
the WLAN USB Dongle w ill g radua lly incre ase the tr ansmission rate again
until it reaches the highest available transmission rate. If you wish to
balance speed versus re lia bi li ty , y ou can se lec t any of the available options.

 Power Mgmt Mode

Allows you to minimize power consum ption and conserv e the battery li fe of
your computer.

 MAC Address

On a Local Area Network (LAN) or other network, the MAC (Media
Access Control) address is your computer’s unique hardware number. On
an Ethernet LAN, it is the same as your Ethernet address.

The communication status is also shown:

 BSSID

Basic Service Set IDentifier of the AP to which the WLAN USB Dongle is
associated.

 Signal Strength

Signal level when receiving the last responding packet. Signal strength is
calculated as the percentage of its signal level measurement relative to the
full signal level.

17

 Link Quality

Shows the point-to-point data transmission quality between your WLAN
USB Dongle and another WLAN station (Ad-Hoc mode) or the
transmission quality between your WLAN USB Dongle and the AP it is
associated with (Infrastructure mode).

To change the configuration param eters press Change, make your chang es th en
click Submit to save your changes.

3.3 Statistics

The Statistics utility allows you to view the statistic (Packets) information
(Data Packets, Mgmt Packets, and Rejected Packets). To renew or update the
list of statistics, press Clear.

3.4 Site Survey

The Site Survey utility allows you to scan all the channels to locate all the APs
(Access Points) within range of your WLAN USB Dongle. When an/various
AP(s) are located, information regarding the BSSID and SSID, signal strength
and channel where the AP ope rates, wheth er or not WEP encry ption is used , and
the operating mode is shown. Click Re-Scan to update the list.

To associate with any of the APs listed, double-click on your choice (on the
BSSID field) and the utility will take you back to the Monitor utility showing
you the parameters of the newly established connection.

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3.5 Encryption

To prevent unauthorized wireless stations from accessing data transmitted over
the network, the Encryption utility offers highly secure data encryption by
allowing you to set four different WEP keys and specify which one to use. To
set encryption:

1. Choose Enabled on the Encryption window.

2. Select any of the available WEP keys (Key #1 to #4) on the WEP Key to

use window. The WEP keys must be in HEX (hexadecimal) format in the
range of a to f, A to F, and 0 to 9.

3. Select the WEP Mode (Mandatory or Optional).

 If Mandatory is selected, then not only must you use WEP encryption

but also any other station you are communicating with must also use
WEP encryption for a link to be established. This requirement is part of
the IEEE 802.11b standard.

 If Optional is selected, then your station can communicate with every

other station regardless if they use WEP encryption or not.

4. Select the Authentication Type (Open System or Shared Key).

5. Press Submit for any changes to take effect.

3.6 Advanced

21

The Advanced utility allows you to change the following advanced
configuration settings:

 Preamble Type

Before selecting Short, make sure that the other station(s) and AP supports
this feature. The WLAN USB D ongle has an auto- detect fea ture th at allow s
it to select the Preamble Type depending on th e Preamb le Type of the AP
it is associated with.

 Fragmentation Threshold

Allows you to set the F rag m entation Thres hold ( thresho ld for the act ivatio n
of the fragmentation mechanism). The Fragmentation function is used for
improving the efficiency when high traffic flows along in the wireless
network. If you often transmit large files in the wireless network, move the
slide bar with your mouse and then use the right and left arrow keyboard
keys to select an exact number. The figure shows the recommended
configuration setting.

 RTS/CTS Threshold

Allows you to set the RTS Threshold (threshold for the activation of the
RTS/CTS mechanism). Transmitter contending for the medium may not
hear each other. RTS/CTS (Request-To-Send/Clear-To-Send) mechanism
can solve this “H idden Node P roblem .” I f the pack et siz e is sm aller than the
preset RTS Threshold size, the RTS/CTS mechanism will not be enabled.
To enable RTS/CTS Threshold, move the slide bar with your mouse and
then use the right and left arrow keyboard keys to select an exact number.
The figure shows the recommended configuration setting.

4 Troubleshooting

This chapter covers potential problems you may run into and the possible
remedies. After each problem description, some instructions are provided to
help you to diagnose and solve the problem.

4.1 Preliminary Checklist

Here are helpful hints to follow before you take further actions when you
encounter problems:

 Try to isolate which part of the computer’s network connection is causing

the problem.

 Make sure that the cable connections are correct and secure (from WLAN

USB Dongle’s USB port to the computer’s USB port).

 Absence of, or conflic t of the WLA N USB D ongle driver. Make sure t hat all

device drivers are correctly installed (refer to chapter 2).

If a problem persists after you follow the instructions in this chapter, contact an
authorized dealer for help.

4.2 Installation Problem

Problems encountered during installation.

 Reconnect one end of the USB cable to the WLAN USB Dongle and the

other end to the computer again. The Power LED indicator on the WLAN
USB Dongle should be ON (red) if the USB cable is properly connected.

 Check if the I/O and IRQ for the WLAN USB Dongle have conflict

problems with other devices connected to your computer.

23

 For Windows 98 / 2000 / Me / XP o perating system , make sure tha t the USB

device driver is installed on your computer.

4.3 Configuration Problem

Problems encountered with the configur at ion.

 Use the Monitor utility of your Configuration & Monitor Application

utility to check the Link Quality of your WLAN USB Dongle with the AP it
is associated with (Infrastructure mode) or with other wireless station(s)
(Ad-Hoc mode).

 Use the Site Survey utility of y our Configuration & Monitor Application

utility to check if there is high interference around the environment.

4.4 Access Point Problem (Infrastructure Mode)

Problems with settin gs for the Acc e ss Point.

 Make sure that the Ac cess Point tha t your WLAN U SB Dongle is associated

with is powered on and all the LEDs are working properly.

 Reconfigure and reset the Access Point.
 Use the Web Manager / Telnet of the Access Point to check whether it is

connected to the network.

4.5 Communication Problem

The WLAN USB Dongle cannot communicate with the computer in the
Ethernet when Infrastructure mode is con figur ed .

 Make sure that the Access Point your WLAN USB Dongle is associated

with is powered on.

 Use the Site Survey utility of the Configuration & Monitor Application

utility to verify if the operating radio channel is in good quality. Or, ch ang e
the Access Point and all the wireless station(s) within the BSSID to another
radio channel.

 Out-of-range situation, which prevents the WLAN USB Dongle from

establishing a wireless c onnection with the network . Move the WLAN USB
Dongle closer to the Access Point it is associated with.

 Make sure that your WLAN USB Dongle is configured with the same

security option (encryption) to the Access Point.

 Make sure that the BSSID is the same as the Access Point for a roaming-

disabled wireless station, o r the ESSID is the sam e as the Acc ess Po int fo r a
roaming-enabled wireless station.

4.6 LAN Problem

I cannot access the network.

 Make sure that the necessary driver(s) is correctly installed.
 Make sure that the network configuration is appropriate.
 Make sure that the user name or password is correct.
 You have moved out of range of the network.
 Turn off power management.

4.7 Software Problem

The Configuration & Monitor Application utility does not work correctly.

 Make sure that the Configuration & Monitor Application utility is

correctly installed (refer to chapter 2).

 If you are sure the operation has stop, reset the computer.

25

A Appendix

A.1 Specifications

NOTE: Specifications are subject to change without notice.

Parts Specifications

Frequency B and ISM Band

2400 to 2483.5 MHz (for USA and Canada)
2400 to 2483.5 MHz (for Europe)
2400 to 2497 MHz (for Japan)

Operating Channel IEEE 802.11b, Direct Sequence Spread Spectrum (DSSS)

11 Channels (for USA and Canada)
13 Channels (for Europe)
14 Channels (for Japan)

Modulation Technique BPSK (low transmit rate) / QPSK (standard transmit rate) /

CCK (high and medium transmit rate)
Data Rate Up to 11 Mbit/s
Antenna Single
Antenna Gain 1 dBi maximum
Radiation Power 16 dBm typical
Receiver Sensitivity –80 dBm at 11 Mbps

–82 dBm at 5.5 Mbps

–87 dBm at 2 Mbps

–90 dBm at 1 Mbps
Power Consumption 5 V, 320 mA TX, 230 mA RX
Dimension (W×H×D) 84×20×92 mm
Weight 48 g
Environment

Temperature
Environment Humidity Operating: 0% to 70%

Operating: 0°C (32°F) to 55°C (131°F)

Storage: –20°C (–3.91°F) to 70°C (158.02°F)

Storage: 0% to 95% (non-condensing)

27

Parts Specifications

Regulation (compliant) Wi-Fi compliant, FCC/CA, CE (Europe), DGT/BSMI
OS Support Windows 98 / Me / 2000 / XP / Linux 2.2.x

A.2 Uninstalling the Utility and Driver

Configuration & Monitor Applicati on Utility

1. Exit the Configuration & Monitor Application utility if i t is currently active.

2. Select the “Uninstall Configuration & Monitor Application” option by

clicking on Start, then Programs, then 802.11 Wireless LAN.

NOTE: If during the uninstall process you receive an error message, insert the driver CD
and try to uninstall again.

WLAN USB Dongle

For Windows 98 / Me / XP –

1. Select the “Network” icon by clicking on Start, then Settings, then Con trol

Panel.

2. Select the “WLAN USB Dongle” from the list and click on Remove.

3. When the system prompts you to re-boot, select “Yes.”

For Windows 2000 –

1. Make sure that the WLAN USB Dongle is plugged into the USB port.

2. Select the WLAN USB Dongle under Device Manager.

3. Click on Uninstall.

G lossary

802.11 The IEEE standard that specifies WLAN MAC and PHY (Physical

Layer) specifications.

802.11b The IEEE standard that specifies Higher-Speed Physical Layer

Extension in the 2.4 GHz band for 5.5 and 11 Mbps WLANs.

802.3

Access Control The prevention of unauthorized usage of network resources by

Access Point
(AP)

Ad-Hoc

Authentication In a multi-user or network operating system, the process by which the

Authenticity

Bandwidth

Base Station In mobile telecommunications, a base station is the central radio

Bit

The IEEE standard that specifies carrier sense media access control and
physical layer specifications for Ethernet LANs.

demanding that users supply a login name and password.
Any entity that has station functionality and provides access to the

distribution services, via the Wireless Medium (WM) for associated
stations.

An Ad-Hoc WLAN is a group of computers each with wireless adapters
connected as an independent WLAN.

system valida t e s a us e r's logon information. A user ' s name and pass word
are compared against an authorized list, and if the system detects a
match, access is granted to the extent specified in the p ermission list for
that user.

Proof that the informatio n came from the person or location that
reportedly sent it. One example of authenticating software is through
digital signatures.

A frequency m e as urement, expres s e d in c y c le s per s e c ond ( he rtz ) or bi ts
per second (bps), of the amount of information that can flow through a
channel. The higher the frequency, the higher the bandwidth.

transmitter/receiver that ma inta ins com munication with the mobile ra di o
telephone sets within its range. In cellular and personal communications
applications, each cell or micro-cell has its own base station, each base
station in turn is interconnected with other cell’s base stations.

(Binary Digit) – A s ing le dig it number in base-2, in ot he r words, either a
one or a zero. The smallest unit of computerized data.

29

Broadband

BSS Basic Service Set. An AP associated with several wireless stations.
Byte

Cryptoanalysis The act of analyzing (or breaking into) secure documents or systems that

Decryption The act of restoring an encrypted file to its original state.
Directional

Antenna

Direct Sequence
Spread Spectrum

EMI ElectroMagnetic Interference. The i nterference by electromagnetic

Encryption

ESSID

Ethernet A very common me thod of networking c om pute r s in a L AN. There are a

Gateway

Gigahertz (GHz) One billion cycles per second. A unit of measure for frequency.
Hertz (Hz) The unit of frequency measure ment; one cycle (of a periodic event such

Of or relating to communications systems in which the medium of
transmission (such as a wire or fiber-optic cable) carries multiple
messages at a time, e ach message m odulated on its own c arrier f requency
by means of modems. Broadband communication is found in wide area
networks.

Abbreviated B. Short for binary term. A unit of data, today almost
always consisting of 8 bi ts. A byte can represent a single character, such
as a letter, a digit, or a punctuation mark. Because a byte repr esents only
a small amount of information, amounts of computer memory and
storage are usually given in kilobytes (1,024 bytes), megabytes
(1,048,576 bytes), or gigabytes (1,073,741,824 bytes).

are protected with encryptio n.

An antenna that concentrates transmission power into a direction thereby
increasing coverage distance at the expense of coverage angle.
Directional antenna types include yagi, patch and parabolic dish.

Abbreviated DSSS. A type of spread spectrum radio transmission that
spreads its signal continuously over a wide frequency band.

signals that can cause reduced data integrity and increased error rates on
transmission channels.

The act of substituting numbers and characters in a file so that the file is
unreadable until it is decrypted. Encryption is usually done using a
mathematical formula that determines how the file is decrypted.

(Extended Service Set IDentification) The ESSID identifies the Service
Set the station is to connect to. Wireless clients associating to the AP
must have the same ESSID.

number of adaptations to the IEEE 802.3 Ethernet standard, including
adaptations with data rates of 10 Mbits/sec and 100 Mbits/sec over
coaxial cable, twisted-pair cable and fiber-optic cable. The la te st v ersion
of Ethernet, Gigabit Ethernet, has a data rate of 1 Gbit/sec.

A device that connects networks using different communications
protocols so that information can be passed from one to the other. A
gateway both transfers information and converts it to a form compatible
with the protocols used by the receiving network.

as a waveform) per second. Frequencies of interest in computers and
electronic dev ices a re of ten meas ured in k ilohe rtz (k Hz = 1,0 00 Hz = 103
Hz), megahertz (MHz = 1,000 kHz = 106 Hz), gigahertz (GHz = 1,000
MHz = 109 Hz), or terahertz (THz = 1,000 GHz = 1012 Hz).

Host

HTTP

IEEE 802
Standards

internet (Lower case I) Any time you connect two or more networks together,

Internet (Upper case I) The worldwide collection of networks and gateways that

Intranet A private network inside a company or organization that uses the same

ISP (Internet
Service
Providers)

Any computer on a network that is a repository for services available to
other computers on the network. It is quite common to have one host
machine provide several services, such as WWW and USENET.

Acronym for HyperText Transfer Protocol. The client/server protocol
used to access information o n the World Wide Web.

A set of standards developed by the IEEE to define methods of access
and control on LANs. The IEEE 802 standards correspond to the
physical and data-link layers of the ISO Open Systems Interconnection
model, but they divide the data -link lay er into two su blay er s. The logical
link control (LLC) subla y er a pplies to all IEEE 802 s ta ndards and c ove rs
station-to-station connections, generation of message frames, and error
control. The MAC sublayer, dealing with network access and collision
detection, differs from one IEEE 802 standard to another: IEEE 802.3 is
used for bus networks that use CSMA/CD, both broadband and
baseband, and the baseband version is based on the Ethernet standard.
IEEE 802.4 is used for bus networks that use token passing, and IEEE

802.5 is used for ring networks that use token passing (token ring
networks). In addition, IEEE 802.6 is an emerging standard for
metropolitan area networks, which transmit data, voice, and video over
distances of more than five kilometers.

you have an internet.

use the TCP/IP suite of protocols to communicate with one another. At
the heart of the Interne t is a back bone of hig h-spe ed data c omm unica tion
lines between major nodes or host com pute r s , c onsis ting of thousands of
commercial, government, educational, and other computer systems, that
route data and messages. One or more Internet nodes can go off line
without endangering the Internet as a whole or causing communications
on the Internet to stop, because no single computer or network controls it.
Currently, the Internet offers a range of services to u sers, such as FTP,
email, the World Wide Web, Usenet news, Gopher, IRC, telnet, and
others. Also called Net.

kinds of software that you would find on the public Internet, but that is
only for internal use.

ISPs provide connections into the Internet for home users and
businesses. There are local, regional, national and global ISPs. You can
think of local ISPs as the gatekeepers into the Internet.

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LAN (Local Area
Network)

Linux A version of the UNIX System V Release 3.0 kernel developed for PCs

MAC (Media
Access Control)

Megahertz (MHz) A measure of frequency equivalent to 1 million cycles per second.
Modulation The conversion of a digital signal to its analog equivalent, especially for

Network

NIC (Network
Interface Card)

Node In LAN, a connection point th at can create, receive, or repeat a message.

Packet A basic message unit for communication across a network. A packet

PCMCIA
(Personal
Computer
Memory Card
International
Association)

POP (Post Office
Protocol)

Personal and other computers within a limited area that are linked by
high-performance cables so that users can exchange information , share
peripherals, and draw on programs and data stored in a dedicated
computer called a file server.

Ranging tremendously in size and complexity, LANs may link only a
few personal computers to an expensive, shared peripheral, such as laser
printer. More complex systems use central computers (file servers) and
allow users to communicate with each other via electronic mail to share
multi-user programs and to access shared databases.

with 80386 and higher-level microprocessors. Linux is distributed free
with source code through BBSs and the Internet, although some
companies distribute it as p art of a commerci al package with Linux­compatible utilities. The Linux kernel works with the GNU utilities.

On a LAN or other netw ork, the MAC a ddress is your c omputer ’s unique
hardware number. (On an Ethernet LAN, it is the same as your Ethernet
address.) The MAC layer fram e s da ta for tra ns mission over the ne twork,
then passes the frame to the ph ysical layer interface where it is
transmitted as a stream of bits.

the purposes of transmitting signals using telephone lines and modems.
Any time you connect two or more computers together so that they can

share resources, you have a computer network. Connect two or more
networks together and you have an internet.

A board that provides network communication capabilities to and from a
computer system. Also called an ad apter.

Nodes include repeaters, file servers, and shared peripherals. In common
usage, however, the term node is synonymous with workstation.

usually includes ro uting inf orm ation, data a nd (som etimes ) error detection
information.

Develops standards for PC Cards, formerly known as PCMCIA Cards.
They are available in three types that are about the same length and width
as credit cards but range in thickness from 3.3 mm (Type I) to 5.0 mm
(Type II) to 10.5 mm (Type III). These cards provide many functions,
including memory storage and acting as landline modems and as WLAN.

This is a common protocol used for sending, receiving and delivering mail
messages.

Port (H/W)

Port An Internet port refers to a number that is part of a URL, appearing after a

Privacy The concept that a user's data, such as stored files and email, is not to be

Protocol A “language” for communicating on a network. Protocols are sets of

Proxy Server A server that performs network operations in lieu of other systems on the

Public Key
Encryption

Radio Frequency
(RF)

Range A linear measure of the distance that a transmitter can send a signal.
RFC (Request for

Comments)

An interface on a computer for co nnecting peripherals or devices to the
computer. A printer port, for example, i s an interface that is designed to
have a printer connected to it. Ports can be defined by specific hardware
(such as a keyboard port) or through software.

colon (:) right after the domain n ame. Every service on an Internet server
listens on a particular port number on that server. Most services have
standard port numbers, e.g., web servers normally listen on port 80.

examined by anyone e lse w ithout that us er's perm ission. A rig ht to priv acy
is not generally recognized on the Internet. Federal law protects only
email in transit or in temporary storage, and only against access by Federal
agencies. Employers often claim a right to inspect any data on their
systems. To obtain pri vacy, th e user must take active measures such as
encryption.

standards or rules used to define, format and transmit data across a
network. There are many different protocols used on networks. For
example, most web pages are transmitted using the HTTP protocol.

network. Proxy servers are most often used as part of a firewall to mask
the identity of users inside a corporate network yet still provide access to
the Internet. When a user connects to a proxy server via a web browser or
other networked application, he submits commands to the proxy server.
The server then su bm its those sam e comm ands to the I nterne t, y e t w ithout
revealing any information about the system that originally requested the
information. Proxy servers are an ideal way to also have all users on a
corporate network channel through one point for all external
communications. Proxy servers can be configured to block certain kinds
of connections and stop some hacks.

An asymmetric scheme that uses a pair of keys for encryption: the public
key encrypts data, and a corresponding secret key decrypts it. For digital
signatures, the process is reversed: the sender uses the secret key to create
a unique electronic number that can be read by anyone possessin g t he
corresponding public key , which verifies that the m essage is truly from the
sender.

The portion of the electromagnetic spectrum with frequencies between 3
kilohertz and 300 gigahertz. This corresponds to wavelengths between 30
kilometers and 0.3 millimeter.

An RFC is an Internet formal document or standard that is the result of
committee drafting and subsequent review by interested parties. Some
RFCs are informational in nature. Of those that are intended to become
Internet standards, the final version of the RFC becomes the standard and
no further comments or changes are permitted. Change can occur,
however, through subsequent RFCs.

33

Roaming

Router

RTS (Request­To-Send)
Threshold

Server

SSL (Secure
Sockets Layer)

Station (STA) Any device that contains an IEEE 802.11 conformant Medium Access

Telnet An Internet protocol that enables Internet users to log on to another

A function that enables one to travel with his mobile end system (e.g.,
WLAN mobile station) throughout a domain (e.g., an ESS) while being
continuously connected to the infrastructure.

An intermediary device on a communications network that expedites
message delivery . O n a si ng le ne twork linking many c ompute r s thro ug h a
mesh of possible connections, a router receives transmitted messages and
forwards them to their correct destinations over the most efficient
available route. On an int erconnected set of LANs using the same
communications protocols, a router serves the somewhat different
function of acting as a link between LANs, enablin g messages to be sent
from one to another.

A signal sent, as from a computer to its modem, to request permission to
transmit. Transmitter contending for the medium may not hear each other.
RTS/CTS mechanism can solve this “Hidden Node Problem.” If the
packet size is smaller than t he preset RTS Threshold size, the RTS/CTS
mechanism will not be enabled.

1. On a LAN, a computer running administrative software that controls
access to the network and i ts resources, such as printers and disk drives,
and provides resources to computers functioning as workstations on the
network.

2. On the Internet or other network, a computer or program that responds
to commands from a client. For example, a file server may contain an
archive of data or program files; when a client submits a request f or a file,
the server transfers a copy of the file to the client.

Technology that allows you to send information that only the server can
read. SSL allows servers and b rowsers to encrypt data as they
communicate with each other. This makes it very difficult for third parties
to understand the communications.

Control (MAC) and physical layer (PHY) interface to the Wireless
Medium (WM).

computer linked to the Internet, including thos e th at cannot directly
communicate with the Int ernet’s TCP/IP protocols. Telnet establishes a
“plain vanilla” computer terminal called a network virtual terminal. This
capability is frequently used to enable communications with bulletin
board systems (BBSs) and mainframe computers. For example, you will
often see hyperlinks to Telnet sessions while browsing the WWW. If you
click such a hyperlink, your browser starts a Telnet helper program, and
you see a text-only command window. In this window, you type
commands and see the remote system’s responses.

URL (Uniform
Resource
Locator)

VPN (Virtual
Private Network)

WAN (Wide Area
Network)

Wired Equivalent
Privacy (WEP)

Wireless Local
Area Network
(WLAN)

Wireless Medium
(WM)

WWW (World
Wide Web)

An address f or a r esourc e on the Inter net. UR Ls a re us ed by Web brows ers
to locate Internet resources. A URL specifies the protocol to be used in
accessing the resource (such as http: for a World Wide Web page or ftp:
for an FTP site), the name of the server on which the resource resides
(such as //www.whitehouse.gov), and, optionally, the path to a resource
(such as an HTML document or a file on that server).

1. A set of nodes on a public network such as the Internet that
communicate among themselves using encryption technology so that their
messages are as safe from being intercepted and und ersto od by
unauthorized users as if the nodes were connected by private lines.

2. A WAN formed of permanent virtual circuits (PVCs) on another
network, especially a network using technologies such as ATM or frame
relay.

A network that uses high-speed, long-distance communications networks
or satellites to connect computers over distances greater than those
traversed by LANs – about 2 miles (3.22 km).

The optional cryptographic confidentiality algorithm specified by IEEE

802.11 used to provide data confidentiality that is subjectively equivalent
to the confidentiality of a wired LAN medium that does not employ
cryptographic techniques to enhance privacy.

A flexible data communications system implemented as an extension to,
or an alternative for a wired LAN. Using radio frequency (RF)
technology, WLANs transmit and receive data over the air, minimizing
the need for wired connections.

The medium use d to implement the transfer of protocol data units (PDUs)
between peer physical layer (PHY) entities of a WLAN.

The total set of interlink ed hy pertex t docume nts residing on H TTP ser vers
all around the worl d. Doc um ents on t he W orld W ide W eb, c alled pag es or
Web pages, are written in HTML (Hypertext Markup Language),
identified by URLs (Uniform Resource Locat ors) that specify the
particular machine and p ath name by which a file can be accessed, and
transmitted from node to node to the end user under HTTP (Hypertext
Transfer Protocol). Codes, called tags, embedded in an HTML document
associate particular words and images in the document with URLs so that
a user can access another file, which may be halfway around the world, at
the press of a key or the click of a mouse. These files may contain text (in
a variety of fonts and styles), graph ics images, movie files, and so unds as
well as Java applets, ActiveX controls, or other small embedded software
programs that execute when t he user activates them by clicking on a link.
A user visiting a Web page also may be able to download files from an
FTP site and send messages to other users via email by using links on the
Web page. Also called w3, W3, Web.

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