3Com 3CRWE920G73 User manual

Quick Start Guide
802.11g 54Mbps WLAN Building to Building
Bridge
Outdoor: 3CRWEASYG73
Indoor: 3CRWE920G73
http://www.3com.com/
Published July 2005
Quick Start guide version2.0.1

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1 Introduction
Thank you for choosing the 3Com Corporation 802.11g 54Mbps Wireless LAN Building to Building Bridge.
The outdoor version of 3Com 802.11g Wireless Bridge is ideal for rough outdoor environments and covering long
distances, whereas the indoor version has a smaller profile to be unobtrusive and can be customized to the application
with a variety of antenna selections. They can be configured as an inter-building wireless bridge with maximum 54Mbps
transmission rate.
This manual will give you a short introduction to the device(s) and will help you to start the Wireless Bridge step by step
quickly. To install and manage this product, you will need a working knowledge of network structures, terms and concepts,
and a professional level of experience in installation procedures for network operation systems under Microsoft Windows.
In this Quick Start Guide you will find just the most basic information needed to install your Wireless Bridge, and get it up
and running. For more detailed installation and configuration please consult the ‘‘3Com 802.11g 54Mbps Wireless
Building to Building Bridge User’s Guide’’.

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2 Package Contents
Please ensure that the package is complete before beginning with the installation. The package should include the
following components:
3CRWE920G73
Indoor 802.11g 54Mbps Building to Building Bridge
3CRWEASYG73
Outdoor 802.11g 54Mbps Building to Building Bridge
•3Com 802.11g Wireless indoor Bridge
•Mounting kit for wall or ceiling mount
•CD-ROM containing software and documentation
•Single-Port PoE Feeder.
•Note: Indoor Bridge does not ship with an antenna.
See www.3com.com or your reseller for antenna
options.
•3Com 802.11g Wireless Outdoor Bridge
•Mounting kit for wall or mast mount
•CD-ROM containing software and documentation
•Single-Port PoE Feeder.
•Lightning arrestor

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3 Hardware Installation
Installing the 3CRWE920G73 Indoor Wireless Bridge
On a flat surface
1 Find a surface that is clear of debris.
2 Set the bridge down on its four rubber feet.
On a wall
1 Use the mounting template as a guide to make two marks 7.40cm (2.91 inches) apart on the wall.
Use the vertical line on the template to ensure that the placement of the marks is plumb to the wall.
2 Drill holes at the marks.
Use a 5-mm (3/16-inch) drill bit if using the provided screw anchors; use a 3-mm (1/8-inich) drill bit if using the screws
only.
3 Install the two flathead screws at the marks on the wall.
Leave the screw heads protruding 6-mm (1/4 inch) from the surface of the wall.
4 Hang the bridge on the screws, using the mounting holes on the back of the bridge.
On an acoustical ceiling
1 Attach the mounting bracket to the back of the bridge with two number 6 panhead screws.
2 Align the T-rail grips with the ceiling T-rail, and adjust them so that they grip the T-rails securely.
3 Tighten the screws on each T-rail grip.
After installation, there may be some play in the fit of the T-rail grips if the T-rails are very narrow. If necessary, add a
shim to achieve a secure grip.

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Connect the antenna
1 Connect one end of the antenna cable to the antenna.
2 Connect the free end of the antenna cable to the connection on the bridge.
Follow the instructions that come with the antenna and follow these general guidelines:
For best performance, place the antenna using the mounting hardware provided with the antenna. Outdoor
placement is especially important if the building is of metal construction or has metal siding. If necessary, you can
mount an antenna inside a building; however, indoor placement reduces the antenna’s effective range.
To ensure the physical safety of anyone near the antenna and to prevent damage to the bridge, follow the building
codes for antenna installations in your area.
Position the antenna so that there are minimal obstacles between it and any other antenna with which it will
communicate. While maintaining a direct line of sight between antennas is not strictly necessary, such an
arrangement helps to ensure a strong signal. Ensure that access is available for routing the antenna cable from the
antenna to the bridge. When mounting an antenna indoors, best performance can be achieved by mounting the
antenna near a window facing the opposite bridge.
Make certain that the antenna and antenna mast are appropriately grounded. Proper grounding prevents injury or
damage from lightning strikes.

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Installing the 3CRWEASYG73 Outdoor Wireless Bridge
Mount the Unit to a Mast
Follow the instructions that come with the bridge mounting hardware and follow the general guidelines listed below.
NOTE:
Mast should extend above
bridge 1 meter (3 ft)
Recommended Pole Diameter =
2’’ --- 2.5’’
Maximum Pole Diameter = 3’’
Bridge may be installed to
freestanding or roof mounted
mast
For best performance, place the antenna outdoors using the mounting hardware provided with the antenna.
Placement is especially important if the building is of metal construction or has metal siding. If necessary, you can
mount an antenna inside a building; however, indoor placement reduces the antenna’s effective range.
To ensure the physical safety of anyone near the antenna and to prevent damage to the bridge, follow the building
codes for antenna installations in your area. This is another good reason to make sure that only a professional
performs the installation.
Keep in mind that in order to comply with FCC radio-frequency radiation exposure guidelines, a minimum body to
antenna distance of 2 meters (6 feet) must be maintained while operating this device.
Ensure that access is available for routing the Ethernet cable from the bridge to the Ethernet connection inside.
Make certain that the antenna mast is appropriately grounded. Proper grounding can prevent injury or damage from
lightning strikes.
After installing the bridge, the highest allowable power level is automatically set when country selection is
configured. Adhering to this configuration ensures compliance with national laws.

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Align and Polarize the Units
For optimal performance, position the antenna so that there are minimal obstacles between it and any other antenna with
which it will communicate. While maintaining a direct line of sight between antennas is not strictly necessary, such a
configuration helps to ensure a strong signal. As mentioned earlier, this is not always possible in long distance
configurations.
Any two bridge units that are to communicate with each other must be set for the same polarization, either horizontally or
vertically. If cross-polarization occurs, the link with either work poorly or not at all. Please refer to the ‘‘Polarization’’
section of the User Guide for further details. The following illustration shows proper alignment, orientation and
polarization for optimal performance.

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Antenna Specification
The following antennas and cables are available from 3Com Corporation:
Antennas
3CWE591 - 6/8dBi Dual-Band
Omni directional Antenna
3CWE598 - 8/10dBi Dual-Band Panel
Antenna
3CWE495 13 dBi Sector-Panel
Directional
3CWE596 - 18/20dBi Dual-Band
Panel Antenna
Ultra Low Loss Coaxial
Antenna Cables:
3CWE580 (6 foot)
3CWE581 (20 foot)
3CWE582 (50 foot)
NOTE: Because of power level restrictions, use of the 3CWE495 13dBi and 3CWE596 18dBi antennas is not
allowed in some countries.
The highest allowable power level is set automatically when you configure antenna selection after installing the bridge.
To comply with power restrictions, identical antennas using 6-foot cable must be separated by at lease the minimum
distances shown below:
Minimum Distance for Full Throughput (approximate)
Antenna (dBi) Meters Yards
18 200 218
13 50 55
8 10 11
4 2 2

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Connect to the Power Source and the Local Network
Connect a twisted pair CAT5 Ethernet cable from
the ’’To Hub/Switch’’ port of the PoE Adapter to a
free port on the hub or switch within the local
network
3CRWE920G73 Indoor Wireless Bridge
3CRWEASYG73 Outdoor Wireless Bridge
NOTE: 3Com recommends that you use a weatherproof and shielded CAT5 cable to help protect the Bridge and your
network equipment from lightning and power surges.
If the Bridge failed to power on or if it lost power, the automatic shutdown feature that is built into the PoE injector may have been
activated to protect the Bridge from power surges. Try resetting the PoE injector.
To reset the PoE injector:
1. On the PoE injector, unplug the CAT5 cables that connect to the Bridge and the Switch.
2. Unplug the power cord, and then wait for the PoE injector to automatically reset itself back to default. The reset process
normally takes about five minutes.
3. Reconnect the power and CAT5 cables to the PoE injector, and then wait for the Bridge to complete its startup process. This
normally takes about one minute.
To verify that you have successfully reconnected the Bridge to the network, use WIDMAN to search for the Bridge. It should appear in
the list of detected network devices. If WIDMAN cannot detect the Bridge, please contact 3Com Customer Support.

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LED Indicators
After the correct connection, the Power LED and the Ethernet link LED of the 3CRWE920G73 indoor bridge should light
up. On the front of the Wireless Bridge you will find three LEDs
POWER
WIRELESS
ETHERNET
1 POWER LED
Off: Power supply connection not available or broken
On: Power supply connection OK
2 WIRELESS activity LED
Off: No activity
Blinking: Sending and receiving data
3 ETHERNET LAN link LED
Off: No LAN connection available
On: LAN connection OK
4. Software Installation
Insert the installation CD-ROM delivered with the 3Com WLAN Building to Building Bridge into your CD-ROM drive
The installation wizard starts automatically and will guide you through the rest of the installation process. If the installation
wizard does not start automatically, run ‘‘setup.exe’’ from the root directory of the installation CD. Then choose to install
the 3Com Wireless Infrastructure Device Manager (WIDMAN) utility for helping you find the Bridge and configure its IP
address.
The 3Com Installation CD contains the following tools and utilities:
3Com Wireless Infrastructure Device Manager (WIDMAN) –an administration tool that helps you selects 3Com
wireless LAN devices and launches their configurations in your Web browser.
3Com 3CDaemon Server Tool ---a firmware upgrade tool that can act in four different capacities:
As a TFTP Server, necessary for firmware upgrades, and backup and restore functions. Use this option if you do not
have a TFTP server set up.
As a SysLog Server, which is necessary to view SysLog messages.
As an optional TFTP Client.
As an optional FTP Server.
[NOTE: It is recommended that you install the 3CDaemon Server tool if you do not already have a firmware tool for
upgrades on your computer.]
To install one of the tools on your computer:
1 Turn on the computer;
2 Insert the 3Com Installation CD in the CD-ROM drive;
The setup menu appears. If it does not appear, you can start the setup menu from the Windows Start menu. For
example: Start > Run > d:setup.exe .
3 In the menu, click Tools and Utilities.
4 In the next screen, click the tool you want to install.
5 Follow the instructions on the screens to complete the installation.
Reboot the computer if prompted to do so.
6 Launch the tool from the Windows Start menu.