- OTC Wireless
Virtual Cable Wi-Fi
Wi-Fi Ethernet Radio
User Guide
Virtual Cable Wi-Fi
Wireless Ethernet
User’s Manual
Copyright
Information in this document is subject to change without notice. Complying with
all applicable copyright laws is the responsibility of the user. No part of this
document may be reproduced or transmitted in any form or by any means,
electronic or mechanical, for any purpose, without the express written permission
of the seller. If, however, your only means of access is electronic, permission to
print one copy is hereby granted.
The seller provides this documentation without warranty, term, or condition of any
kind. The seller may make improvements or changes in the product(s) and/or the
program(s) described in this documentation at any time.
Other product and company names herein may be trademarks of their respective
owners.
Copyright 2001, 2002 OTC Wireless, Inc. All rights reserved.
Revision: v1.13
Table of Contents
Virtual Cable Wi-Fi User’s Manual
Chapter 1 INTRODUCTION
Data Sheet
1
2
Chapter 2 INSTALLATION
Installing the Hardware
Power
Ethernet connection
Status LEDs
Installing the Utility Software
System Requirement
Installation
4
4
4
4
5
6
6
6
Chapter 3 UTILITY SOFTWARE
Use the Utility Program
Overview of the Tabs
Configure Virtual Cable Wi-Fi
Configure Virtual Cable Wi-Fi as an Access Point
Configure Virtual Cable Wi-Fi as a Station
Set up the Encryption
Obtain the Link Information
View the Packet Statistics
Uninstall the Utility Software
7
7
7
7
8
12
13
15
16
17
Chapter 4 TROUBLESHOOTING
Blank Pages Appear When Open the Utility Program
No Radio Link When Set Up As a Station
No Radio Link When Set Up As an AP
No Network Connection While the Radio Link is Good
Poor Link Quality
Radio Interference
Technical Support
18
18
18
18
19
19
20
20
Appendix A: LIMITED WARRANTY
Wireless LAN Hardware
Wireless LAN Software
21
21
21
Appendix B: REGULATORY COMPLIANCE
22
Appendix C: APPLICATION SCENARIOS
PC to PC connections
Multiple Wireless PC connections
Wireless LAN/WAN Connections
Multiple Wireless LAN Connection
Multiple LAN through a Single Wireless Connection
23
23
24
25
26
27
GLOSSARY
28
Chapter 1
INTRODUCTION
The Virtual Cable Wi-Fi is an 802.11b compliant radio with a 10-BaseT interface,
Power-Over-Ethernet (POE), and an indoor/ outdoor enclosure. The Virtual
Cable Wi-Fi is available with an integrated 9dBi or 15 dBi patch antenna, or an
N-type external antenna connector.
Note: Throughout this user guide, the terms “Virtual cable Wi-Fi” and
“Wireless Ethernet adapter” are used interchangeably.
Model numbers for the Virtual Cable Wi-Fi are as follows:
Product Name
AVCW-100
AVCW-200
AVCW-109
AVCW-209
AVCW-115
AVCW-215
Description
802.11b outdoor radio with external antenna connector, access point
802.11b outdoor radio with external antenna connector, station
802.11b outdoor radio with 9 dBi built-in antenna, access point
802.11b outdoor radio with 9 dBi built-in antenna, station
802.11b outdoor radio with 15 dBi built-in antenna, access point
802.11b outdoor radio with 15 dBi built-in antenna, station
Two features separate Virtual Cable Wi-Fi from many other 802.11b-compliant
radios. Firstly, this 802.11b-compliant (Wi-Fi) radio can be configured as either a
Station or an Access Point (AP). Secondly, when configured as a Station, the 10BaseT interface affords it a true plug-and-play feature that is unavailable from
any other 802.11b radios that are based on either a PCMCIA or a USB interface
and require the installation of a driver on the host computer. This driver-less
feature also means that the operation of the radio is OS (operating system)
independent.
When configured as a Station, the driver-less feature enables wireless
connectivity for any computing devices/systems installed with any OS (operating
system), as long as an Ethernet communication port is available. Special
computing/networking devices, such as printer servers, POS (point of sales)
machines may not even have an easy way of installing a driver for a radio,
making the Wi-Fi Virtual Cable an ideal solution.
With link distances of several miles, the Wi-Fi Virtual cable can even be
connected to a router to interconnect networks or provide access to the Internet.
When configured as an AP, Virtual Cable Wi-Fi offers a no-frill, seamless way of
fitting a wireless network into an existing wired LAN infrastructure. It does not
even require the assignment of an extra IP address. Existing wired-network
resources such as DHCP, VPN, firewall, etc., reach across the Virtual Cable WiFi AP to the client workstations with total transparency. Unlike many other
802.11b Access Points on the market, which offer network functions that are
duplicative to the existing network, this AP simply wirelessly collects a group of
1
workstations or other kinds of computing devices into the existing network—just
like a hub.
A Utility program is needed to pre-configure Virtual Cable Wi-Fi prior to putting
the radio in operation. And the Utility program can be used to monitor the
communication condition once the radio is in operation. Once configured, the
radio runs self-sufficiently without the aid of any driver program in the host
computer connected to the radio. This Utility program therefore is intended to be,
in most cases, just a tool for the network operators. An end user simply plugs the
pre-configured radio into a host computer or a network device equipped with a
RJ-45 receptacle without ever being exposed to this Utility program. The Utility
program is simple to install and easy to use through its graphic user interface.
The details are described in Chapter 3.
Virtual Cable Wi-Fi Radio
Key Features
Highest degree of security provided by Dynamic WEP encryption key distribution
Configurable as either an Access Point or a Station
Plug & Play as a Station—
o No driver on the host device is required for radio operation
o Radio operation is independent of the operating system on the host device (Windows
98/2000/ME, Linux, Unix, embedded, etc.), as long as an Ethernet port is properly supported
Simple, effective and user selectable network access control methods as an AP
Industry standard IEEE 802.11b-compliant wireless interface; Interoperable with AP and Client
radios from other vendors (Wi-Fi certified)
Ethernet (802.3 compliant) host interface to enable true Plug & Play
11Mbps data rate and automatic selection of lower data rate (5.5, 2 and 1 Mbps) in degraded RF
environment
Integrated 9 or 15 dBi antennas, or external antenna connectors for last mile wireless LAN
Applications
Standard-compliant wireless networking for computers and equipment with an Ethernet interface
Where Plug & Play is essential
Embedded devices, tools, instruments, equipment and appliances that can benefit from the reconfigurability of wireless link yet are unfriendly to the installation of device-drivers
o Enterprise routers that require wireless WAN input
o Control/monitor equipment
2
Specifications
Virtual Cable Wi-Fi (AVCW 100/200/109/209/115/215)
Model
802.11 and 802.11b
Standard
Ethernet, 802.3, RJ-45 receptacle
Host Interface
2.4GHz – 2.495GHz
Frequency
11 channels (US, Canada), 13 channels (Europe), 13
RF Channels
channels (Japan)
Transmission power 14dBm at antenna input typical
Receiver sensitivity -80dBm @1e-5 BER typical
Dipole antenna with ~2dBi gain
Antenna
11, 5.5, 2 or 1 Mbps fixed rate, or configured to
Data Rate
automatic rate selection
CCK, Direct Sequence Spread Spectrum
Modulation
~1200 ft in open space
Link Distance
Support both the ad hoc mode and the infrastructure
Network Types
mode
Support the standard 64-bit WEP and the optional 128Data Encryption
bit WEP
Support User-enabled Dynamic WEP key
generation and distribution
Selectable levels of access control: SSID hidden in
Network Security
beacon, exact SSID match and MAC-address-based
allowed-list; password protected AP configuration
Output: 5V, 2.6A; Input:100-120V, 50-60Hz, ~1.0A
AC adapter
max
<480mA (max. reached in transmit-mode)
Current
consumption
4: Power, Transmission, Receiving, Link/EthernetLED Indicators
connection
-10°C – 50°C
Operating
Temperature
FCC part 15
Regulation
Compliance
3
Chapter 2
INSTALLATION
Installing the Hardware
Power
This radio uses OTC's Power-Over-Ethernet system to bring power and data to
the radio over OTC's specialized Ariel Category-5 Ethernet cable (supplied with
the standard purchase). This is accomplished by using a DC Injector that sits
between the Network and the Radio and uses a standard wall outlet for DC
power.
To setup the Virtual Cable Wi-Fi, follow the instructions below:
1. Connect the bundled 5V AC Adapter to the DC input on the bottom of the DC
Injector unit.
2. Connect the Ariel Category-5 cable that extends from the radio to the port on
the DC Injector labeled, "Radio".
3. If configured as an access point, connect a crossover Category-5 Ethernet
cable from a hub, switch or router to the port on the DC Injector labeled
"Network". If you are connecting an access point directly to a PC, use a straightthrough Category-5 Ethernet cable.
If configured as a station, connect a straight-through Category-5 Ethernet cable
from a PC or Router to the port on the DC Injector labeled "Network."
Ethernet connection
Observe the yellow LED to check the status of the Ethernet connection:
If the yellow LED stays on continuously, then the Ethernet connection to the host
computer or device is not made. Check your UTP cable and cable type, and
replace if necessary. If the yellow LED is flickering, and power is on to the
device, then the Ethernet connection between the host computer and the
Wireless Ethernet Adapter is correct. If one cannot communicate, and the yellow
LED is off, you may want to re-position the Virtual Cable Wi-Fi to a different
location for better RF reception. You may also want to check if the unit is
configured with the proper RF channel and security settings by using the Utility
software.
4
Once the hardware is checked out to work properly with the intended host device
or network equipment, the radio can be secured to a desired location using the
bundled mounting kit.
Above: (left) schematic of Virtual Cable Wi-Fi Access Point connected to a network.
(right) schematic of Virtual Cable Wi-Fi Station connected to a terminal PC.
Ethernet Connection (station)
When configured as a Station, the Virtual Cable Wi-Fi can be connected to a
computer’s Ethernet port, or a router's WAN port via the included Straightthrough UTP cable. Please note that, as dictated by the 802.11 standards, only
one MAC address can be supported by a Station radio. As a result, a Virtual
Cable Wi-Fi configured as a Station will not function properly when
connected to a hub or switch plugged in with multiple computers/networkdevices. So as a rule, straight-through cable is always used to connect a Virtual
Cable Wi-Fi Station to a computer or a network device.
If you wish to connect multiple PCs via a single Virtual Cable WiFi station, see
"Appendix C: Virtual Cable Wi-Fi Applications"
Status LEDs
Use the LED status indicators to make sure that the Virtual Cable Wi-Fi station is
communicating properly:
LED
ON
Color
RED
Light Blinking Pattern
Steady on
RX
GREEN
Steady on
TX
RED
on, when transmitting RF signal
LINK
YELLOW
Flickering when communicating over the Ethernet
port; steady-on when Ethernet connection is absent
5
Installing the Utility Software
System Requirements
To use the Virtual Cable Wi-Fi utilities software, your computer must meet the
following minimum requirements:
Windows® 95 (OSR2)/ 98 (SEC)/ME/2000/XP
Ethernet capable computer with RJ-45 port (either built-in or add-on NIC)
Installation
To install the utility program, simply insert the CD-ROM provided and the
installation process will finish with you clicking a few “OK’s”. The installation
copies the Utility program and its run-time support (components of Visual Basic)
onto the host computer without altering any settings of the host computer.
Notice that the operation of the Virtual Cable Wi-Fi is independent of the Utility
Program. Therefore it is NOT necessary to install the Utility on the networkdevice/computer that you plan to install the Virtual Cable Wi-Fi. For example, if
you plan to connect a printer server wirelessly to the network with the Virtual
Cable Wi-Fi, you do not need to have the Utility Program installed on the printer
server—you will not be able to! In this example, you configure the Virtual Cable
Wi-Fi as a Station on a PC installed with the Utility Program, disconnect it from
the PC, then connect it to the printer server. While the Utility program must run
on a computer equipped with Microsoft Windows, the radio can operate with
computers/devices of any OS.
Also notice that to configure or monitor the radio with the Utility program, the
computer running the Utility program can be either directly connected to the radio
or connected to the same subnet the radio is connected to.
6
Chapter 3
UTILITY SOFTWARE
Use the Utility Program
Once the radio is properly turned on and connected either directly to the
computer running the Utility program or
to a port on the same subnet, the Utility
is ready for use. To start the Utility
program from your Microsoft Windows,
click “Start”, then “Program”, move to
locate the “Virtual Cable Wi-Fi” group
and click on the Utility program icon to
launch the Utility program.
Overview of the Tabs
There are five tabs inside the Utility
graphic interface. The “About” tab
displays the software version
information. The “Link Info “, “Station
Configuration”, “WLAN Statistics” and
“Encryption” tabs will be discussed
more in the ensuing subsections.
The OK and Exit buttons at the bottom
Screen-Shot #1
of the frame are common to all tabs.
Clicking the OK button signals the successful completion of the use of the Utility
program. The program applies the modifications made to all tabs and exits.
Clicking the Exit button exits the program without changing the setting of the
radio. The Refresh and the Apply buttons are available for the “Configuration”
and the “Encryption” tabs. Clicking the Refresh button at any moment causes the
program to retrieve and display the most updated configuration information from
the radio at that moment. Clicking the Apply button updates the radio setting
without exiting the program. Clicking the Apply button under the “Access Point”
sub-tab of the “Configuration” tab, however, requires correct entry of a password
before the radio settings can be updated. See details below. Clicking the Apply
button also causes the program to automatically perform a function in order to
confirm the updating action by displaying the updated information. Sometimes a
blank screen may appear after the Apply or the Refresh button is clicked. This
indicates that either the radio is extremely busy or there is a problem with the
Ethernet connection. Either try clicking the Apply or the Refresh button again or
check your Ethernet connection.
Configure Virtual Cable Wi-Fi
There are two sub-tabs under the “Configuration” tab, Station and Access Point.
If the “Station” page is displayed, clicking on the “Access Point” sub-tab switch
the display to the Access Point page. If the Virtual Cable Wi-Fi is currently
7
configured as a Station, all the parameter fields appear dimmed and are not
modifiable. This is illustrated in screen-shot #2.
Configure Virtual Cable Wi-Fi as an Access Point
By checking the “Change Role to AP” (red-arrowed in screen-shot #3), most
Screen-Shot #2
Screen-Shot #3
parameter fields become undimmed and modifiable, as seen in screen-shot #3 .
With the exception of the “MAC” field, and sometimes the “Allowed Station List”
field, each field can be modified and uploaded into the radio by clicking the Apply
button without exiting the program, or by clicking the
OK button right before exiting the program. This
uploading action, however, is password protected. A
password challenge screen (upper portion of screenshot #4) pops up as the Apply button is clicked. The
uploading takes place only after the password
Screen-Shot #4
challenge is successfully met. A “try again” message
appears, as shown in the lower portion of screen-shot
#4, if incorrect password is entered. The radio is
shipped with a default password
entered on your “Quick Start Guide”.
Change this password immediately. Make sure that the new
password is securely saved somewhere. In case the password
is lost, you must call OTC to obtain a temporary password and
a special binary file to get into the radio to reset the password.
Change Password: The password that protects the Access
Point settings can be changed by clicking this button (redcircled in screen-shot #3). The pop-out screen for changing
password is shown in screen-shot #5. The new password is
Screen-Shot #5
8
uploaded into the radio, just like other parameters on this sub-tab, when the old
password is correctly verified.
Each field on this “Access Point” sub-tab is explained below.
Device Name: Allows the user to enter a user-defined name for the radio. Up to
32 bytes can be used.
MAC: Displays the MAC address of the radio when it is configured as an AP.
This field cannot be modified.
SSID: Service Set Identity is used by a station radio when issuing
Association/Re-association Requests to the Access Point. The
Access Point uses the match of the SSID as one of the optional conditions for
granting or refuting association. (See more on this topic in “Enhanced Sec.”
below.) A Manager/operator of the network chooses this SSID. When a SSID is
first introduced, it needs to be manually typed in. After a SSID is used once, the
Utility program remembers the SSID and allows it to be selected out of the pulldown list for re-use. The special SSID name “any”, once selected, allows an
Virtual Cable Wi-Fi to wander across Service Sets with different SSID’s without
the need to manually obtain and reset the SSID every time. Whether the Station
radio’s association request is accepted or rejected by an AP, however, is entirely
determined by the local network management, not guaranteed by the use of
“any” as the SSID. When “any” is chosen, the SSID field display turns blank. The
special role of “any” works only in the Infrastructure mode.
Enhanced Sec.: There are two aspects to the security of a WiFi radio network:
access control and data encryption.
More details on data encryption are
given in the section discussing
Encryption. Independent of whether
data encryption is used or not, the
access of a Station to the network can
be restricted. The Virtual Cable Wi-Fi
Access Point can be set up to offer
four different levels of access control
for the wireless network associated
with it. Refer to screen-shot #6, a pulldown menu is used to select the level
of network security. Level 0,
[Disabled], basically leaves the access
to the network entirely open. Stations
with “any” (see the section
“Configuration the Virtual Cable Wi-Fi
as a Station” for more explanations) as Screen-Shot #6
the SSID, for example, is allowed to
join without any restriction. Selecting Level 1, [Hide SSID in Beacon], causes the
AP radio to send beacons without the SSID. This minimizes the chance for an
eavesdropping radio to capture and utilize the SSID for more damaging intrusion
9
to the network. At Level 2, [Hide SSID, Match exact SSID], this AP grants a
Station association only when the Station submits in its association request
exactly the same SSID as the SSID entered in this sub-tab. The tightest level of
network access control is implemented in Level 3, [Hide SSID, Match SSID, Use
Allowed List], add one additional criterion for a Station to gain access to the
network associated with this AP—its MAC address must appear in the “Allowed
Station List” (see below) shown in the lower-right corner of this sub-tab.
Allowed Station List: The MAC addresses of the Stations in the network need to
be entered here if the Level 3, [Hide
SSID, Match SSID, Use Allowed List],
has been chosen as the access control
method. When Level 3, [Hide SSID,
Match SSID, Use Allowed List], is
selected, the Add, the Delete and the
Exit buttons below the “Allowed List”
panel become undimmed and
selectable (Screen-shot #6). An input
box (screen-shot #7) for entering the
MAC address of a Station to be allowed
to join the network appears when the
Add button is clicked. Type in the MAC
address and click the Done button, the
newly added MAC address should
appear in the list. As usual, the Apply
button needs to be clicked before this
Screen-shot #7
addition truly takes effect. To delete a
MAC address from the “Allowed Station
List”, simply highlight the MAC address and click the Delete button. Clicking on
the Exit button right after either the Add or the Delete action, but before pressing
the Apply button, will cancel either the Add or the Delete action.
Note that if the Station radio is a Wireless PCMCIA Card or a Wireless USB
Adapter, the MAC address is directly associated with the Card or the Adapter.
The MAC addresses can be either read off the labels on the Card/Adapter, or
from the utility programs, or from the host computers (e.g., “ipconfig /all” in DOS,
“ifconfig” in Linux, or the “Network” setting in the “Control Panel” of Microsoft
Windows). However, if the Station is an Virtual Cable Wi-Fi, the MAC
address is NOT the MAC address on the label of the radio, it is, instead, the
MAC address of the Ethernet port of the host computer/device.
Tx Rate: The RF environment sometimes can be hostile to the highest data rate
available to Virtual Cable Wi-fi. That gives rise to the need for trading off between
data rate and link robustness. The six choices in the pull-down list allow the
network manager to select that optimum trade off.
Authentication Option: When the “open system” option is chosen, no encryption
is applied to the packets exchanged between this Station radio and another
10
radio. Communication with another radio (a station or an AP), however, can be
successful only if the other radio also is set up to communicate in the “open
system” mode. When the “shared key” option is chosen, the “Encryption” tab of
the Utility program must be properly filled out.
Fragmentation Threshold: In the presence of hostile RF environment, such as
interference, frames longer than this threshold numbers in bytes are divided prior
to transmission into one or more fragments equal in length to the fragmentation
threshold. The default value is set at 2436 bytes, the maximum 802.11 data
frame size, such that no frames are ever fragmented.
RTS Threshold: To minimize the potential packet collision associated with hidden
nodes in a wireless network, 80211 standard has the option to complete a
“Request to Send(RTS)” and “Clear to Send(CTS)” two-frame exchange prior to
sending the real data. This obviously reduces the throughput of the real data.
Since the probability of packet collision increases with the size of the packets
transmitted, an optimum trade-off between data-throughput and data-integrity
may be reached by turning on the two-frame exchange only for data packets
exceeding a certain size. The number entered in this field is that threshold packet
size in Bytes. For example, if “500” is entered, data packets with sizes less than
500 bytes are transmitted without being preceded by the RTS-CTS exchange
and thereby taking a small risk of getting corrupted by packet collisions. If “2346”
(the maximum 802.11 data frame size) or a larger number is entered, then every
data packet is transmitted without being preceded by the RTS-CTS exchange
and thereby maximizing the data throughput.
Channel: Click on the arrow and highlight the desired frequency (channel) for the
radio network. A minimum of 20MHz separation from the frequency of an
adjacent AP is required.
Beacon Interval: An Access Point periodically sends out “Beacon” packets to
broadcast information for the Stations already associated with the AP or for
Stations yet to associate with it. This field specifies how frequently the beacon
packet is sent. The default value is 100 mSec. For a relatively “fixed” network,
where Stations roaming in and out is infrequent, the interval can be long to
minimize the overhead usage of the bandwidth.
DTIM Period: An Access Point generates a Traffic Indication Map (TIM) to
identify the Stations that have data buffered inside the AP. The TIM is included in
the Beacon sent out by the AP. A Station determines that data packets are
buffered for it by the AP and takes appropriate actions by listening to the beacon
and interpreting a TIM. A special delivery TIM (DTIM) is used to signal that
broadcast/multicast frames buffered at the AP will be sent immediately following
the beacon that contains the DTIM. This is necessary only when the AP detects
that at least one of the Stations associated to it is in the Power Save (PS) mode.
DTIM period is measured in terms of beacon intervals. The default setting is 10
beacon intervals. This means one out every 10 beacons sent by the AP contains
DTIM. If prior knowledge is available that Stations in a particular network rarely
11
uses the PS mode, a high value for DTIM Period should be entered to minimize
the overhead usage of the bandwidth.
Configure Virtual Cable Wi-Fi as a Station
Click on the “Station” sub-tab to display the “Station” page if the “Access Point”
page is on top after clicking the
“Configuration” tab. Similar to the case of
configuring the radio for AP, checking the
“Change Role to Station” undims the page
and makes most fields modifiable.
Some of the fields on the Station sub-tab
are identical to those on the “Access
Point” sub-tab. Please refer to the
“Access Point” section for explanation of
these fields. Those fields not on the
“Access Point” sub-tab and those with a
different usage (red-arrowed items in
screen-shot #8) are described below.
MAC: This is not a modifiable field. When
set up as a Station, this field displays the
Screen-Shot #8
MAC address that is unique to the radio
immediately after the radio is turned on. Once it is connected to a host
computer/device, however, the MAC address changes to that of the Ethernet port
of the host computer/device. It this host computer/device MAC address that
should be entered into the “Allowed Station List” of an Virtual Cable Wi-Fi Access
Point or a WiFi AP with the “Allowed Station List” feature. Notice that it may be
necessary to initiate the transmission of a network packet from the host
computer/device after the Virtual Cable Wi-Fi Station is connected in order for the
Station radio to capture the MAC address of the host computer/device. Power off
then on or reset the host computer/device while the Virtual Cable Wi-Fi Station is
actively connected can achieve the same.
The need of a Virtual Cable Wi-Fi Station to learn the MAC address of the host
computer/device should be contrasted to absence of such need by a PCMCIA or
a USB Station radio. In the case of the PCMCIA or USB Station radio, higherlayer packets, such as IP, are delivered to the radio without an Ethernet header.
The PCMCIA or USB radio (in conjunction with its driver) adds the Ethernet
header with a MAC address unique to the radio. In the case of Virtual Cable WiFi, however, the packets delivered to the radio are already fully 802.3 compliant
and with an Ethernet header, in which the MAC address is that of the Ethernet
card of the host computer/device. If the Virtual Cable Wi-Fi were to encapsulate
the Ethernet packet with another header containing a MAC address unique to the
radio, this header would not have been removed by another target 802.11compliant radio and therefore would prevent the proper delivery of these packets.
12
Network Type: Two possible types to select from: the “Infrastructure” type where
all Stations communicate through an Access Point (AP), and the “Ad hoc” type
where all Stations communicate directly with each other.
PS Mode: Power Saving can be enabled only when “Infrastructure” is selected
for the “Network Type”.
Channel: This field is modifiable only when the “Ad hoc” type is selected for
“Network Type”. The Station automatically scans for the right channel to join
when operated in the “Infrastructure” mode. In the “Ad hoc” mode, the Station
also automatically scans for the right channel to join an existing “ad hoc” Service
Set. However, when the Station is the first station to start an ad hoc network, it
will stay on the channel selected in this field to wait for other stations to join.
Set up the Encryption
This page allows users to set up the 802.11 Wired Equivalent Privacy (WEP) to
protect the content of the data frames from eavesdropping.
Encryption: Three selections are available. The 64-bit encryption is currently the
802.11 standard. The 128-bit encryption is supported by equipment from a
limited number of vendors. Notice that the “user-controlled” portion of the 64-bit
encryption is just 40 bits and that for the 128-bit encryption is just 104 bits—3bytes of the encryption key are internal to the encryption algorithm.
Default WEP Key Entry: Virtual Cable Wi-Fi currently supports only the default
(shared) WEP key scheme defined in the 802.11 standard, not the mapped key
Screen-Shot #9
Screen-Shot #10
13
scheme. A set of four keys needs to be created in the default-key scheme. There
are two ways of generating the four keys. Choosing “Create with Pass-Phrase”
and entering a pass-phrase causes the radio to generate the default keys
following a set algorithm--the same pass-phrase applied to another Virtual Cable
Wi-Fi radio will generate an identical set of default keys. The same pass-phrase
applied to other Wi-Fi radios, however, may result in very different keys. For this
reason, clicking the Apply button after entering the pass-phrase will cause the 4
sets of keys being temporarily displayed under “Manual Entry” as if they were
entered manually. (See screen-shots #9 and #10, the display in screen-shot #10
is dimmed and not modifiable.) These displayed keys can be copied down and
manually entered for radios other than Virtual Cable Wi-Fi to assure
interoperability. Clicking the button or switching to another tab and then return
will cause the keys to be hidden again. Up to 64 characters can be entered for
the pass-phrase. “Manual Entry” requires typing in all four keys. 5 bytes (10
characters) need to be entered if the 64-bit encryption option is chosen—the
other 8 bytes (16 characters are dimmed and not modifiable). 13 bytes (26
characters) need to be entered if the 128-bit encryption option is chosen.
Use Dynamic WEP Key: The
encryption scheme adopted by the
802.11 standard is static in nature.
Such static scheme has been proven
to be vulnerable to cracking. Internet
downloadable software such as
Airsnort can crack a static encryption
key in as short a time as 15 min..
Virtual Cable Wi-Fi counters such
Screen-Shot #11
security hole by generating and
distributing fresh WEP keys in time
intervals less than 12 min.. This
capability is built on top of the default
key scheme. The default keys (64-bit
or 128-bit) are still set up in the same
manner described above. Except that
Key #4 is no longer available as a
selection for transmission (see
Transmission Key Sel below). The
default keys in this situation are only
used in the authentication process. A Station must respond to an authentication
challenge with one of the default keys in the usual manner defined by the 802.11
standards. Upon successful authentication, the AP uses one of the default keys
to send the seed of the Current WEP key (the one generated by the AP and has
no relation to any of the default keys) to the Station. From that point on, the data
exchanged between the AP and the Station are encrypted with this AP controlled
WEP key. In a time interval shorter than 12 min., the seed of a fresh key is sent
to the Station encrypted with the Current Key. Basically, the static default keys
are NOT used for data encryption when the dynamic WEP key is enabled. Note
that the highest level of Access Control (Hide SSID, Match SSID, Use Allowed
14
List) should be selected on the AP in order to benefit the most from the use of the
Dynamic WEP Key feature.
Transmission Key Sel: (Transmission Key Selection) One of the 4 default keys
needs to be selected for transmitting data frames. The radio can de-encrypt
received data encrypted in any one of
the four default keys, but it uses only
one of the default keys for transmitting
its data. When Use Dynamic WEP Key
is checked, only 3 default keys are
available for selection (Screen Shot
#11). Note that once the Dynamic
WEP Key is in force, the Transmission
Key Selection (Screen Shot#12) made
by the user is only used in the
authentication process and is
irrelevant in the encryption of
transmitted data.
WEP Key Factor: The number here
determines how frequently a certain
register for the encryption is changed.
The smaller the number is the securer
the communication.
Screen Shot#12
Obtain Link Information
Screen-shot #13
Screen-shot #14
15
This page provides an overview of the setup of the radio. The “Device” field
displays the Device Name assigned to the radio and the firmware installed. The
“Current Status” field displays the few configuration parameters most pertinent to
setting up a WiFi link. In addition, if the radio’s role is Station, the “Link Quality”
and “Signal Strength” are automatically retrieved from the radio and displayed
every 2 seconds. “Link Quality” measures the percentage of accurately
transmitted data packets. “Signal Strength” directly measures the amount of RF
energy received relative to a “maximum” expected for the best condition. The two
measures are related, but could differ due to various reasons. In general, as a
first step toward maximizing Link Quality, one should try to maximize the Signal
Strength by moving the radio around. If the radio’s role is AP, the “Link Quality”
and “Signal Strength” are not displayed (Screen Shot #14).
View Packet Statistics
In addition to the “Link Quality” on the “Link Info” tab, which is available only
Screen-Shot #15
Screen-Shot #16
when the radio is set as a Station, several statistics on the packet (frame) traffic
through the radio, either as a Station or as an AP, are displayed on the “WLAN
Statistics” tab. From the “Total Transmitted Frames” and the “Total Transmitted
Retry Frames”, one can get a picture of the transmission frame-error-rate.
Similarly, from the “Total Received Frames” and the “Total Received Error
Frames”, one can get a picture of the receiving frame-error-rate. The “Total
Transmitted Octets” and “Total Received Octets” provide a measure of the total
traffic through the radio during the “Refresh Time Interval”. The calculated traffic
is displayed in KB/Sec. Note that these traffic numbers are a measure of the
amount of data passing through the radio at a given moment, and it should not
be confused with the “throughput capability” of the radio. To automatically display
16
these statistics on a regular interval, simply enter the desired “Refresh Time
Interval” and then press the Go button. Notice that in this mode the Refresh
button at the bottom of the tab is dimmed and unavailable (Screen Shot#15). If
the “Refresh Time Interval” is left empty, the Refresh button at the bottom of the
tab is undimmed (Screen Shot#16) and can be pressed to display the statistics
accumulated inside the radio up to that point. Clicking the Refresh button at this
point also clears, upon the completion of the retrieval of, the statistics inside the
radio. The display stays unchanged until the Refresh button is pressed again.
Notice also that in this manual mode throughputs in Bits/Sec are not calculated
due the imprecise timing.
Uninstall the Utility Software
If you need to uninstall the Utility software for any reason, complete the following
steps:
1. Close all programs that are currently running.
2. Click the Window Start button, point to Settings and then click the Control
Panel.
3. Double click the Add/Remove Programs icon.
4. Click the Virtual Cable Wi-Fi.
This will uninstall the utility program from your computer.
17
Chapter 4
TROUBLESHOOTING
Blank Pages Appear When Open the Utility Program
This is either because the radio is extremely busy on the RF side or because the
Ethernet connection is problematic. Try to hit the Refresh button a few times. If
the blank-page condition persists, it is unlikely that the problem is caused by a
busy radio. Check your Ethernet connection. Make sure you use at least a
legitimate CAT-3 cable, but preferably a CAT-5. Make sure that it is a straightthrough cable between the radio and the computer, or a crossover cable between
the radio and the hub, if a hub is involved. Check to make sure that the Ethernet
card of the computer running the Utility program is functional.
No Radio Link When Set Up As a Station
If the Virtual Cable Wi-Fi is intended to function as a Station but the “Link Quality”
indicator on the “Link Info” tab shows 0%, check the following possible causes:
•
Make sure that a target radio, an AP or another Station, is turned on and
operating properly.
•
Make sure that the “Signal Strength” indicator on the “Link Info” tab is not
zero. A minimum of 20% is recommended. If the “Signal Strength” is less
than 20%, the distance between the Virtual Cable Wi-Fi and the targeted
radio (an AP or another Station) may be too far. Decrease the distance to
see if the radio link can be established.
•
Make sure that the Virtual Cable Wi-Fi is set up as a Station, not an AP.
•
Make sure that the SSID is “any” or the same as that for the Access Point
if operating in the infrastructure mode, or the same as that of the other
Stations if operating in the Ad Hoc mode.
•
Make sure that all the access controls are satisfied if operating in an
infrastructure mode (i.e., connecting to an AP). For example, is the MAC
address of the host computer/device of the Virtual Cable Wi-Fi Station
entered in the AP?
•
Make sure that the encryption keys are entered correctly if WEP is
enabled.
•
Make sure that there is no RF interference present in the radio network.
No Radio Link When Set Up As an AP
If the Virtual Cable Wi-Fi is set up as an AP, but one or more target Station
radios cannot link with it, check the following:
18
•
Make sure that the MAC address of the Station in question is properly
entered into the “Allowed Station List” of the AP if enhanced security level
3, [Hide SSID, Match SSID, Use Allowed List], is chosen.
•
Make sure that the Station in question has exactly the same SSID as the
AP if enhanced security level 2 or 3 is chosen.
•
Make sure that the Station in question has exactly the same WEP keys as
the AP. Special attention should be paid to this item if “pass-phrase” is
used to generate the WEP keys and the Station radios in question are
NOT an Virtual Cable Wi-Fi.
No Network Connection While the Radio Link is Good
If the “Link Quality” indicator shows good link quality on the “Link Info” tab, but
the host computer/device cannot be connected to the network
•
Make sure that the Yellow LED on the radio is NOT constantly ON. If it is,
Ethernet connection is questionable.
•
Make sure the Ethernet Adapter of the host computer/device is properly
installed.
•
Make sure that the UTP cable connecting the radio and the host device
meets at least the CAT-3 standard and has a Straight-through connection,
not a Cross-over.
•
Make sure that the Virtual Cable Wi-Fi, when set up as a Station, is not
connected to a hub with multiple computers/devices plugged in.
•
Make sure that the IP address of the host computer/device is properly set
up for the network.
•
Make sure that the host computer/device has initiated some packet traffic
since the radio was turned on. (That is the failure of the network
connection is not just determined by trying to access the host from a
remote point in the network.) Reset or re-power the host with the Virtual
Cable Wi-Fi turned on may be necessary in order for the Virtual Cable WiFi to “learn” the MAC address of the host computer.
Poor Link Quality
If the “Signal Strength” is reasonably high (>20%) and the “Link Quality” is not
zero, but the “Link Quality” stays in the Poor range, it could be due to one of the
following reasons:
•
Make sure that radio interference is not present in the radio network.
19
•
Make sure that the radio is not surrounded by many strongly reflecting
(metallic) surfaces. With multiple reflecting surfaces between the radio in
question and the target radio, a severe “multi-path” problem may
introduce high bit error rate despite a strong “Signal Strength”.
•
Make sure that there is not a condition of severe packet collision caused
by a “hidden node” problem. A “hidden node” problem is the situation
where the RF signal from two or more Station radios cannot reach each
other (but can reach the AP). In such situation, multiple Stations may
attempt to transmit data packet to the AP at the same time and therefore
cause packet collision. To solve this problem, either re-arrange the
Stations in question such that the RF signals are mutually sensible by all
Stations, or turn-on the RTS/CTS protocol by setting the “RTS threshold”
on the “Station” sub-tab to a reasonably small value (500, for example).
There is no guarantee that the packet collision can be entirely eliminated
by invoking RTS/CTS protocol, but the severity can be reduced enough to
see visible improvement of the link quality.
Radio Interference
You may be able to eliminate RF interference by trying the following:
• Find the “channel” used by the source of the interference and coordinate
your network and the interference source to be on channels that are at
least 20MHz, but preferably 30MHz, apart.
•
Reseat the Virtual Cable Wi-Fi radio to a location where the interference is
minimized; in general, increase the distance between the wireless
computers and the device causing the radio interference.
•
Avoid using 2.4GHz cordless phone in the vicinity of the radio
•
Keep the computer with the Virtual Cable Wi-Fi radio away from the
microwave oven and large metal objects.
•
Consult the dealer or an experienced radio technician for help.
Technical Support
If problems are still not solved, please contact our Technical Support to obtain
further assistance.
Call: 1-800-770-6698 in USA
Call: 011-510-490-8288 outside of USA
E-mail: [email protected]
20
Appendix A:
LIMITED WARRANTY
Wireless LAN Hardware
The seller warrants to the end user (“Customer”) that this hardware product will
be free from defects in workmanship and materials, under normal use and
service, for one (1) year from the date of purchase from the seller or its
authorized reseller. The seller’s sole obligation under this express warranty shall
be, at the seller’s option and expense, to repair the defective product or part,
deliver to Customer an equivalent product or part to replace the defective item, or
if neither of the two foregoing options is reasonably available, The seller may, in
its sole discretion, refund to the Customer the purchase price paid for the
defective product.
All products that are replaced will become the property of the seller.
Replacement products may be new or reconditioned.
Wireless LAN Software
The seller warrants to Customer that each software program licensed from it ,
except as noted below, will perform in substantial conformance to its program
specifications, for a period of one (1) year from the date of purchase from the
seller or its authorized reseller. The seller warrants the media containing
software against failure during the warranty period. No updates are provided. The
seller’s sole obligation under this express warranty shall be, at the seller’s option
and expense, to refund the purchase price paid by Customer for any defective
software product, or to replace any defective media with software which
substantially conforms to applicable seller published specifications. Customer
assumes responsibility for the selection of the appropriate application programs
and associated reference materials. The seller makes no warranty or
representation that its software products will meet Customer’s requirements or
work in combination with any hardware or software applications products
provided by third parties, that the operation of the software products will be
uninterrupted or error free, or that all defects in the software products will
be corrected. For any third party products listed in the seller software product
documentation or specifications as being compatible, the seller will make
reasonable efforts to provide compatibility, except where the non-compatibility is
caused by a defect in the third party’s product or from use of the software product
not in accordance with the seller’s published specifications or user manual.
21
Appendix B:
REGULATORY COMPLIANCE
FCC Part 15 Declaration of Conformity (DoC)
The following equipment:
Product Name: Wireless Ethernet Adapter
Model Number: Virtual Cable Wi-Fi WLAN is herewith confirmed to comply with
the requirements of FCC Part 15 rules. The operation is subject to the following
two conditions:
1. This device may not cause harmful interference, and
2. This device must accept any interference received, including interference that
may cause undesired operation.
FCC ID of AVCW100/200: MKZ0208WODU0E
FCC ID of AVCW109/209: MKZ0207WODU09
FCC Rules and Regulations - Part 15
Warning: This device has been tested and found to comply with the limits for a
Class B digital device pursuant to Part 15 of the Federal Communications
Commissions Rules and Regulations. These limits are designed to provide
reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in accordance with
the instruction manual, may cause harmful interference to radio communications.
However, there 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 and correct the interference by one or more of
the following measures:
. Relocate your WLAN equipped laptop computer.
. Increase the separation between the WLAN equipped laptop computer and
other electronics.
. Connect the WLAN equipped laptop computer into an outlet on a circuit different
from that of other electronics.
. Consult the dealer or an experienced radio/TV technician for help.
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
minimum distance of 20cm between the radiator & your body.
22
Appendix C:
APPLICATION SCENARIOS
PC-to-PC Connection
Station
Antenna
Antenna
Station
RF Cable
Cat. 5
Cable
AC/DC
Adapter
RF Cable
Cat. 5
Cable
DC Injector
Cat. 5 Cable
Workstation
AC/DC
Adapter
DC Injector
Cat. 5 Cable
Workstation
PC-to-PC Connections: Each PC is connected to an AVCW unit configured as a station operating
in AdHoc mode. All antennas must be positioned such that they can link with all other stations.
23
Multiple Wireless PC Connections
Antenna
Station
RF
Cable
Cat. 5
Cable
Omni Antenna
AC/DC
Adapter
DC Injector
Access Point
Cat. 5
Cable
Cat. 5 Cable
Workstation
RF Cable
Antenna
AC/DC
Adapter
DC Injector
Station
RF
Cable
Cat. 5
Cable
Cat. 5 Cable
DSL Router
AC/DC
Adapter
DC Injector
Cat. 5 Cable
Workstation
Multiple Wireless PC Connections: Each PC is connected to an AVCW unit configured as a
station operating in Infrastructure mode. All antennas must be positioned such that they can link
with the Access Point antenna. All workstations become part of a single LAN and route through a
common gateway.
24
Wireless LAN/WAN Connections
.
Access Point
Antenna
Station
Antenna
Router
RF cable
Cat. 5
Cable
AC/DC
Adapter
RF Cable
DC Injector
Cat. 5
Cable
DC
Injector
Workstation
Workstation
Workstation
Cat. 5 Cable
Internet Router
Wireless LAN/WAN Connections: Remote LAN uses a router to NAT to a single MAC address
and IP. LAN uses a single AWVC station configured in infrastructure mode. Station antenna
must be positioned such that it can link with the Access Point antenna.
25
Multiple Wireless LAN Connection
Station
Antenna
Router
RF Cable
Omni Antenna
Cat. 5
Cable
DC
Injector
Workstation
Access Point
Workstation
Cat. 5
Cable
Workstation
RF Cable
AC/DC
Adapter
Station
Antenna
DC Injector
Cat. 5 Cable
Router
RF Cable
Internet Router
Cat. 5
Cable
DC
Injector
Workstation
Workstation
Workstation
Multiple Wireless LANs: Each LAN uses a router to NAT to a single MAC address and IP. Each
LAN uses an AWVC station configured in infrastructure mode. All station antennas must be
positioned such that they can link with the Access Point antenna.
26
Multiple LAN through a Single Wireless Connector
Antenna
Statio
n
Router
RF Cable
DC
Injector
Cat. 5
Cable
Omni Antenna
Access Point
Router/
Switch
Cat. 5
Cable
AC/DC
Adapter
Router/
Switch
RF Cable
Workstation
DC Injector
Workstation
Workstation
Workstation
Workstation
Workstation
Cat. 5 Cable
Internet Router
.
.
.
Multiple LANs Through a Single Wireless Link: Each LAN uses a separate router than converges
on a single router to present a single MAC address and IP. Single station is configured in
infrastructure mode. Station antenna must be positioned such that it links with the Access Point
antenna.
27
GLOSSARY
10BaseT An IEEE standard (802.3) for operating 10 Mbps Ethernet networks
(LANs) with twisted pair cabling and a wiring hub.
Access Point An internetworking device that seamlessly connects wired and
wireless networks. Access Points combined with a distributed system support the
creation of multiple radio cells that enable roaming throughout a facility.
Ad Hoc Network A network composed solely of stations within mutual
communication range of each other (no Access Point connected). The Ad Hoc
network offers peer-to-peer connections between workstations, allowing
communication between computers within range that have an 802.11
DSSS compatible PC card installed.
BSS Basic Service Set. A set of stations controlled by a single coordination
function.
Channel A medium used to pass data units that can be used simultaneously in
the same volume of space by other channels of the same physical layer, with an
acceptably low frame error ratio due to the absence of mutual interference.
CSMA/CA Carrier Sensing Multiple Access/Collision Avoidance The medium
access control method used by the 802.11 standard. Basically, a radio can start
transmitting signal only when no carrier from another radio is sensed and after a
randomized wait time has expired.
DTIM Delivery Traffic Indication Map The Stations that currently have data held
in an AP are identified by a Traffic Indication Map (TIM). This TIM is included in
the beacon sent by an AP. DTIM is a special type of TIM. When a DTIM is sent in
a beacon frame, it signals that all the broadcast and multicast data held for
Stations in PS mode will be sent immediately following the beacon frame.
Encapsulated An Ethernet address mode that treats the entire Ethernet packet
as a whole and places it inside an 802.11 frame along with a new header.
ESS Extended Service Set. A set of one or more interconnected Basic Service
Sets (BSSs) and integrated Local Area Networks (LANs) can be configured as an
Extended Service Set.
Ethernet The most widely used medium access method, which is defined by the
IEEE 802.3 standard. Ethernet is normally a shared media LAN; i.e., all the
devices on the network segment share the total bandwidth. Ethernet networks
operate at 10Mbps/100Mbps using CSMA/CD to run over 10BaseT/100BaseT
cables.
Hidden Node The situation where two or more radios in a multiple-radio network
fail to detect the RF signals from each other. For example, in a 3-radio network,
28
radio 2 and 3 both have good link to radio 1. Radio 2 and 3, however, are
isolated from each other by, say, a metal wall. Radio 2 therefore is a “hidden
node” to radio 3, and vice versa. Since an 802.11 network relies on the
CSMA/CA protocol to control network access, hidden nodes break down the
Carrier Sensing mechanism of controlling medium access because two or more
radios cannot sense the carrier from each other.
IEEE 802.11 The IEEE 802.xx is a set of specifications for LANs from the
Institute of Electrical and Electronic Engineers (IEEE). Most wired networks
conform to 802.3, the specification for CSMA/CD-based Ethernet networks or
802.5, the specification for token ring networks. 802.11 defines the standard
for wireless LANs encompassing three incompatible (non-interoperable)
technologies: Frequency Hopping Spread Spectrum (FHSS), Direct Sequence
Spread Spectrum (DSSS), and Infrared. IEEE standards ensure interoperability
between systems of the same type.
Infrastructure Network A wireless network centered about an Access Point. In
this environment, the Access Point not only provides communication with the
wired network but also mediates wireless network traffic in the immediate
neighborhood.
IP Internet Protocol. The standard protocol within TCP/IP that defines the basic
unit of information passed across an Internet connection by breaking down data
messages into packets, routing and transporting the packets over network
connections, then reassembling the packets at their destination. IP corresponds
to the network layer in the ISO/OSI model.
IP Address An IP address is a 32-bit number that identifies each sender or
receiver of information sent across the Internet. An IP address has two parts: the
identifier of a particular network on the Internet and an identifier of the particular
device (which can be a server or a workstation) within that network.
ISP Internet Service Provider. An organization that provides access to the
Internet. Small ISPs provide service via modem and ISDN while the larger ones
also offer private line hookups (T1, fractional T1, etc.).
LAN Local Area Network. A communication network that serves users within a
defined geographical area. The benefits include the sharing of Internet access,
files, and equipment, such as printers and storage devices. Special network
cabling (10BaseT) is often used to connect the PCs together.
NAT Network Address Translation. The translation of an Internet Protocol
address (IP address) used within one network to a different IP address known
within another network. One network is designated the internal network and the
other is the external. The internal network then appears as one entity to the
outside world.
29
PCMCIA Personal Computer Memory Card International Association. This
Association develops standards for PC cards, formerly known as PCMCIA cards.
These cards are available in three types, and are about the same length and
width as credit cards. However, the different cards range in thickness from 3.3
mm (Type I) to 5.0 mm (Type II) to 10.5 mm (Type III). These cards can be used
for various functions, including memory storage, landline modems, and wireless
modems.
PS Mode Power Save Mode. This mode is recommended for devices where
power consumption is a major concern, such as battery-powered devices.
Radio Frequency RF, Terms: GHz, MHz, Hz —The international unit for
measuring frequency is Hertz (Hz), equivalent to the older unit of cycles per
second. One megahertz (MHz) is one Million-Hertz. One gigahertz (GHz) is one
Billion-Hertz. The standard U.S. electrical power frequency is 60 Hz, the
AM broadcast radio frequency band is 0.55–1.6 MHz, the FM broadcast radio
frequency band is 88–108 MHz, and wireless 802.11 LANs operate at 2.4GHz.
SSID Service Set ID. A group name shared by every member of a wireless
network
Station The Station is the component that connects a host computer or device
to the wireless medium. It may be referred to as the Wireless Network Adapter or
the Wireless Network Interface Card.
WEP Wired Equivalent Privacy. The optional cryptographic confidentiality
algorithm specified by 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.
30
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