ELPRO, 9/12 Billabong Street, Stafford QLD, 4053, Australia.
Tel: +61 7 33528600 Fax: +61 7 33528677 Email: sales@elprotech.com
Web: www.elprotech.com
ELPRO Technical Support Help-line America (866) 7134409 Rest of the world +617 3352 8624
Version 1.8.1
245U-E Wireless Ethernet
Modem & Device Server
User Manual
245U-E Wireless Ethernet User Manual
Page 2 Dec 2011
ATTENTION!
Incorrect termination of supply wires may
cause internal damage and will void warranty.
To ensure your 245U-E enjoys a long life,
double check ALL your connections with the
user manual before turning the power on.
CAUTION:
To comply with FCC RF Exposure requirements in section 1.1310 of the FCC Rules, antennas used with this
device must be installed to provide a separation distance of at least 20 cm from all persons to satisfy RF
exposure compliance.
DO NOT:
Operate the transmitter when someone is within 20 cm of the antenna
Operate the transmitter unless all RF connectors are secure and any open connectors are properly
terminated.
Operate the equipment near electrical blasting caps or in an explosive atmosphere
All equipment must be properly grounded for safe operations. All equipment should be serviced only by a qualified
technician.
Chapter One 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 3 Page 3
FCC NOTICE:
This device complies with Part 15.247 of the FCC Rules.
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.
This device must be operated as supplied by ELPRO Technologies. Any changes or modifications made to the
device without the written consent of ELPRO Technologies may void the user’s authority to operate the device.
End user products that have this device embedded must be installed by experienced radio and antenna personnel, or
supplied with non-standard antenna connectors, and antennas available from vendors specified by ELPRO. Please
contact ELPRO for end user antenna and connector recommendations.
Part 15 – This device has been tested and found to comply with the limits for a Class B digital device, pursuant to
Part15 of the FCC rules (Code of Federal Regulations 47CFR Part 15). Operation is subject to the
condition that this device does not cause harmful interference.
Notice – Any changes or modifications not expressly approved by ELPRO could void the user’s authority to
operate this equipment.
THIS DEVICE SHOULD ONLY BE CONNECTED TO PCS THAT ARE COVERED BY EITHER FCC
DOC OR ARE FCC CERTIFIED.
NOTICES: SAFETY
Exposure to RF energy is an important safety consideration. The FCC has adopted a safety standard for human
exposure to radio frequency electromagnetic energy emitted by FCC regulated equipment as a result of its actions
in Docket 93-62 and OET Bulletin 65 Edition 97-01.
UL NOTICE:
1. The Wireless Ethernet module is to be installed by trained personnel / licensed electricians only and
installation must be carried out in accordance with the instructions listed in the Installation Guide and
applicable local regulatory codes.
2. The units are intended for Restricted Access Locations.
3. The Wireless Ethernet module is intended to be installed in a final enclosure, rated IP54, before use
outdoors.
4. The Equipment shall be powered using an external Listed Power Supply with LPS outputs or a Class 2
Power Supply.
5. The Wireless Ethernet module must be properly grounded for surge protection before use.
6. If installed in a hazardous environment coaxial cable shall be installed in a metallic conduit
245U-E Wireless Ethernet User Manual
Page 4 Dec 2011
IMPORTANT NOTICE
ELPRO products are designed to be used in industrial environments, by experienced industrial engineering
personnel with adequate knowledge of safety design considerations.
ELPRO radio products are used on unprotected license-free radio bands with radio noise and interference. The
products are designed to operate in the presence of noise and interference, however in an extreme case, radio noise
and interference could cause product operation delays or operation failure. Like all industrial electronic products,
ELPRO products can fail in a variety of modes due to misuse, age, or malfunction. We recommend that users and
designers design systems using design techniques intended to prevent personal injury or damage during product
operation, and provide failure tolerant systems to prevent personal injury or damage in the event of product failure.
Designers must warn users of the equipment or systems if adequate protection against failure has not been included
in the system design. Designers must include this Important Notice in operating procedures and system manuals.
These products should not be used in non-industrial applications, or life-support systems, without consulting
ELPRO first.
1. A radio license is not required in some countries, provided the module is installed using the aerial and
equipment configuration described in the 245U-E Installation Guide. Check with your local distributor
for further information on regulations.
2. Operation is authorized by the radio frequency regulatory authority in your country on a non-protection
basis. Although all care is taken in the design of these units, there is no responsibility taken for sources of
external interference. Systems should be designed to be tolerant of these operational delays.
3. To avoid the risk of electrocution, the aerial, aerial cable, serial cables and all terminals of the 245U-E
module should be electrically protected. To provide maximum surge and lightning protection, the module
should be connected to a suitable earth and the aerial, aerial cable, serial cables and the module should be
installed as recommended in the Installation Guide.
4. To avoid accidents during maintenance or adjustment of remotely controlled equipment, all equipment
should be first disconnected from the 245U-E module during these adjustments. Equipment should carry
clear markings to indicate remote or automatic operation. E.g. "This equipment is remotely controlled and
may start without warning. Isolate at the switchboard before attempting adjustments."
5. The 245U-E module is not suitable for use in explosive environments without additional protection.
6. The 245U-E Operates using the same Radio frequencies and communication protocols as commercially
available off-the shelf equipment. If your system is not adequately secured, third parties may be able to
gain access to your data or gain control of your equipment via the radio link. Before deploying a system
make sure you have considered the security aspects of your installation carefully.
RELEASE NOTICE:
This is the December 2011 release of the 245U-E Ethernet Modem User Manual version 1.8.1 which applies to
version 2.0 Modem firmware.
Chapter One 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 5 Page 5
Limited Lifetime Warranty, Disclaimer and Limitation of Remedies
ELPRO products are warranted free from manufacturing defects for the ―serviceable lifetime‖ of the product. The
―serviceable lifetime‖ is limited to the availability of electronic components. If the serviceable life is reached in
less than three years following the original purchase from ELPRO, ELPRO will replace the product with an
equivalent product if an equivalent product is available.
This warranty does not extend to the following:
Failures caused by the operation of the equipment outside the particular product's specification, or
Use of the module not in accordance with this User Manual, or
Abuse, misuse, neglect or damage by external causes, or
Repairs, alterations, modifications undertaken other than by an authorized Service Agent.
ELPRO liability under this warranty is limited to the replacement or repair of the product. This warranty is in lieu
of and exclusive of all other warranties. This warranty does not indemnify the purchaser of products for any
consequential claim for damages or loss of operations or profits and ELPRO is not liable for any consequential
damages or loss of operations or profits resulting from the use of these products. ELPRO is not liable for damages,
losses, costs, injury or harm incurred as a consequence of any representations, warranties or conditions made by
ELPRO or its representatives or by any other party, except as expressed solely in this document.
GNU FREE DOCUMENTATION LICENCE:
Copyright (C) 2009 ELPRO Technologies.
ELPRO Technologies is using a part of Free Software code under the GNU General Public License in operating the
―245U-E ‖ product. This General Public License applies to most of the Free Software Foundation’s code and to any
other program whose authors commit by using it. The Free Software is copyrighted by Free Software Foundation,
Inc. and the program is licensed ―As is‖ without warranty of any kind. Users are free to contact Elpro Technologies
at the following Email Address: sales@elprotech.com for instructions on how to obtain the source code used in the
―245U-E‖.
A copy of the license is included in the section entitled "GNU Free Documentation License".
245U-E Wireless Ethernet User Manual
Page 6 Dec 2011
CONTENTS
CHAPTER 1 INTRODUCTION .................................................................................................................... 9
1.1 NETWORK TOPOLOGY ................................................................................................................................. 9
1.2 GETTING STARTED QUICKLY .................................................................................................................... 12
CHAPTER 2 INSTALLATION ................................................................................................................... 13
2.0 GENERAL .................................................................................................................................................... 13
2.1 ANTENNA INSTALLATION ........................................................................................................................... 13
Antenna Diversity ......................................................................................................................................................... 14
Line-of-sight installations ............................................................................................................................................. 14
Antennas ....................................................................................................................................................................... 14
Installation tips .............................................................................................................................................................. 15
Dipole and Collinear antennas ...................................................................................................................................... 16
Directional antennas. ..................................................................................................................................................... 16
2.2 POWER SUPPLY .......................................................................................................................................... 17
2.3 SERIAL CONNECTIONS ............................................................................................................................... 17
RS232 Serial Port .......................................................................................................................................................... 17
DB9 Connector Pinouts ................................................................................................................................................. 18
RS485 Serial Port .......................................................................................................................................................... 18
2.4 DISCRETE (DIGITAL) INPUT/OUTPUT ................................................................ ................................ ........ 19
CHAPTER 3 OPERATION ......................................................................................................................... 20
3.0 START-UP ................................ ................................................................ .................................................... 20
―Access Point‖ Start-up (245U-E-G) ............................................................................................................................ 20
―Access Point‖ Start-up (245U-E-A) ............................................................................................................................ 20
―Client‖ Start-up............................................................................................................................................................ 20
Link Establishment ........................................................................................................................................................ 20
How a Link connection is lost ....................................................................................................................................... 21
Roaming Clients ............................................................................................................................................................ 21
LED Indication ................................................................................................ .............................................................. 21
3.1 SELECTING A CHANNEL ............................................................................................................................. 21
802.11b/g (2.4GHz) ...................................................................................................................................................... 21
802.11a (5GHz) ............................................................................................................................................................. 23
Dynamic Frequency Selection (DFS) ............................................................................................................................ 23
3.2 CONFIGURING THE UNIT FOR THE FIRST TIME ......................................................................................... 24
Default Configuration ................................................................................................................................................... 24
Accessing Configuration for the first time .................................................................................................................... 24
Method 1 - Set PC to same network as 245U-E ............................................................................................................ 25
Method 2 - Set 245U-E Network address to match the local network ........................................................................... 26
3.3 QUICK START CONFIGURATION ................................................................................................................ 28
3.4 NETWORK CONFIGURATION ...................................................................................................................... 29
Network Settings Webpage Fields ................................................................................................................................ 30
3.5 SPANNING TREE ALGORITHM .................................................................................................................... 31
3.6 COMPATIBILITY ......................................................................................................................................... 32
3 Address (Layer 3 Bridge) & 4 Address Mode .............................................................................................. 32
What Addresses are in a wireless Ethernet data frame? ................................................................................................ 32
Packets between AP and Client ..................................................................................................................................... 32
240U-E Compatibility ...................................................................................................................................... 32
3.7 SECURITY MENU ........................................................................................................................................ 33
WEP (64 bit) & (128 bit) ............................................................................................................................................... 34
Encryption Keys 1 to 4 .................................................................................................................................................. 34
WPA / WPA2 ................................................................................................................................................................ 34
WPA Enterprise - Supplicant Configuration ................................................................................................................. 35
WPA Enterprise - Authenticator Configuration ............................................................................................................ 35
3.8 NORMAL OPERATION ................................................................................................................................. 36
Transparent Bridge Operation ....................................................................................................................................... 36
Chapter One 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 7 Page 7
Router Operation ........................................................................................................................................................... 36
3.9 RADIO CONFIGURATION ............................................................................................................................ 37
Channel Selection.......................................................................................................................................................... 38
3.10 ADVANCED RADIO CONFIGURATION .................................................................................................... 39
Fixed Noise Floor .......................................................................................................................................................... 40
3.11 SERIAL PORT CONFIGURATION ............................................................................................................ 40
RS-232 PPP Server ....................................................................................................................................................... 40
Serial Gateway (Server/Client/Multicast) ..................................................................................................................... 41
Serial Gateway (Modbus - Modbus RTU to TCP) ........................................................................................................ 42
Modbus TCP to RTU Gateway ..................................................................................................................................... 42
3.12 SERIAL MENU ........................................................................................................................................ 43
RS-232 / RS485 Serial Port Configuration (Common to all) ........................................................................................ 43
RS232 PPP Server (Only RS232).................................................................................................................................. 43
RS-232 / RS485 Serial Gateway Mode ......................................................................................................................... 43
RS-232 / RS485 Modbus TCP/RTU Converter............................................................................................................. 44
3.13 MULTICAST PIPE MANAGER ................................................................................................................. 45
3.14 DIGITAL INPUT/OUTPUT ....................................................................................................................... 46
3.15 MODBUS I/O TRANSFER ........................................................................................................................ 46
Modbus TCP Configuration on I/O Transfer Menu: ..................................................................................................... 48
Modbus TCP Client Mappings on I/O Transfer Menu: ................................................................................................. 49
3.16 ROAMING ............................................................................................................................................... 49
3.17 REPEATERS (WDS) ................................................................................................................................ 51
Example – Extending range using WDS .......................................................................................................... 52
Example - Roaming with WDS Access Points ................................................................................................ 53
Example – Adding Redundancy ...................................................................................................................... 54
Example – WDS Routed Network ................................................................................................................... 56
WDS Connections: ........................................................................................................................................................ 58
3.18 ROUTING ................................................................................................................................................ 59
3.19 FILTERING ............................................................................................................................................ 61
MAC Address Filter Configuration: ................................................................................................................ 62
IP Address Filter Configuration: ...................................................................................................................... 62
ARP Filter Configuration ................................................................................................................................. 63
3.20 DHCP CLIENT CONFIGURATION ......................................................................................................... 63
3.21 DHCP SERVER CONFIGURATION ......................................................................................................... 64
3.22 DNS SERVER CONFIGURATION ............................................................................................................. 64
3.23 MODULE INFORMATION CONFIGURATION ........................................................................................... 65
Module Information Webpage Fields ............................................................................................................................ 65
3.24 CONFIGURATION EXAMPLES ................................................................................................................ 66
Setting a 245U-E to Factory Default Settings .................................................................................................. 66
Extending a wired network .............................................................................................................................. 66
Access Point Configuration ........................................................................................................................................... 66
Client 1 Configuration ................................................................................................................................................... 66
Client 2 Configuration ................................................................................................................................................... 66
Connecting two separate networks together .................................................................................................... 67
LAN A Configuration ................................................................................................................................................... 67
LAN B Configuration.................................................................................................................................................... 67
Access Point Configuration ........................................................................................................................................... 67
Client Configuration ...................................................................................................................................................... 67
Extending range of a network with a Repeater hop ......................................................................................... 68
CHAPTER 4 DIAGNOSTICS ...................................................................................................................... 69
4.0 DIAGNOSTICS CHART ................................................................................................................................. 69
4.1 CONNECTIVITY ........................................................................................................................................... 69
Site Survey ....................................................................................................................................................... 70
4.2 CHANNEL SURVEY (UTILISATION) ............................................................................................................ 71
Channel Utilisation on a Live System: .......................................................................................................................... 71
245U-E Wireless Ethernet User Manual
Page 8 Dec 2011
Using Channel Utilisation for Channel Selection or RF Path Testing: .......................................................................... 71
Diagnosing Low Throughput: ....................................................................................................................................... 71
Solutions for High Channel Utilisation: ........................................................................................................................ 71
4.3 CUSTOM SURVEY ........................................................................................................................................ 73
4.4 THROUGHPUT TEST ................................................................................................................................... 75
Internal Throughput Test ............................................................................................................................................... 75
Throughput and Repeaters ............................................................................................................................................ 77
4.5 STATISTICS ................................................................................................................................................. 78
Wireless Statistics ......................................................................................................................................................... 78
Network Traffic Analysis .............................................................................................................................................. 79
4.6 SYSTEM TOOLS ........................................................................................................................................... 79
4.7 TESTING RADIO PATHS .............................................................................................................................. 80
Iperf Throughput Test ................................................................................................................................................... 80
Internal Radio Test ........................................................................................................................................................ 80
4.8 REMOTE CONFIGURATION ......................................................................................................................... 82
4.9 INTERNAL DIAGNOSTICS MODBUS REGISTERS ......................................................................................... 82
Connection Information ................................................................................................................................................ 82
4.10 UTILITIES ............................................................................................................................................... 84
―Ping‖ ............................................................................................................................................................................ 84
‖Ipconfig‖ ..................................................................................................................................................................... 85
‖Route‖ ......................................................................................................................................................................... 85
CHAPTER 5 SPECIFICATIONS ................................................................................................................ 87
APPENDIX A FIRMWARE UPGRADE ................................................................................................. 89
Web based Upgrade ......................................................................................................................................... 89
APPENDIX B GLOSSARY ............................................................................................................................ 90
APPENDIX C CHANNELS ....................................................................................................................... 94
802.11b/g ......................................................................................................................................................... 94
802.11b/g Turbo ............................................................................................................................................... 94
802.11a – Maximum Radio Transmitter Power ............................................................................................... 95
802.11a Turbo - Maximum Radio Transmitter Power ..................................................................................... 95
APPENDIX D 802.11A & TX POWER ................................................................................................... 96
dB to mWatt Conversion ................................................................................................................................. 96
APPENDIX E EXTERNAL IPERF TEST ................................................................................................... 97
Materials ....................................................................................................................................................................... 97
Installation ..................................................................................................................................................................... 97
Iperf Applications.......................................................................................................................................................... 97
JPerf Application ........................................................................................................................................................... 99
APPENDIX F GNU FREE DOC LICENCE .............................................................................................. 100
Version 2, June 1991 ................................................................................................................................................... 100
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION .................................... 100
NO WARRANTY ....................................................................................................................................................... 102
Chapter One 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 9 Page 9
Chapter 1 INTRODUCTION
The 245U-E Industrial 802.11 Wireless Ethernet module provide wireless connections between Ethernet devices
and/or Ethernet wired networks (LAN’s). They each comply with their relevant IEEE 802.11 standard.
The 245U-E is available in a range of different models with different RF power and frequency options suitable for
your country’s local radio regulations.
245U-E-G 802.11 b/g 400mW max power
245U-E-A 802.11 a 400mW max power
The above models have the same functionality but use a different radio to communicate. The different radios do not
communicate with each other, e.g. a 245U-E-G will not communicate with a 245U-E-A. Only modules of the same
type are able to communicate wirelessly to each other.
Throughout this manual, any reference to ―245U-E‖ refers to one of the above models.
The 245U-E-G model uses a 2.4GHz Direct Sequence Spread Spectrum (DSSS) wireless transceiver. Users pick a
20 MHz channel with 5 MHz channel spacing from the available 13 starting with the first channel centered on
2.412 GHz. Some limitations depending on country see Appendix C for channel selections.
Note that regulations in North America permit 11 x 2.4GHz channels and Europe permits 13 x 2.4GHz channels.
The 245U-E-A uses a 5 GHz Direct Sequence Spread Spectrum (DSSS) wireless transceiver and users must select
appropriate channel, transmit power, etc allowable in that country.
Please check with your ELPRO representative for the permitted channel usage in your country.
See Appendix C for channels selections.
The 245U-E unit also provides two serial connections as well as the Ethernet connections. It is possible to use all
three data connections concurrently, allowing the 245U-E to act as a Device Server. Wireless connections can be
made between serial devices and Ethernet devices. The 245U-E provides connection functionality between serial
―Modbus RTU‖ devices and Ethernet ―Modbus TCP‖ devices. Appropriate driver applications will be required in
the host devices to handle other protocols.
The 245U-E has a standard RJ45 Ethernet connection which will operate at up to 100Mbit/sec. The module will
transmit the Ethernet messages on the wireless band at rates between 1 and 54 Mbit/sec & 6 and 54 Mbit/sec
depending on model, band, encryption methods and radio paths.
1.1 Network Topology
The 245U-E is an Ethernet device, and must be configured as part of an Ethernet network. Each 245U-E must be
configured as an:
―Access Point‖ or ―Sta‖, ―Station‖,
‖Client‖
―Bridge‖ or ―Router‖.
You can also connect to the 245U-E via a
RS232 or RS485 serial port using serial server
or PPP (point-to-point) protocol. PPP allows
the 245U-E to connect serial communications
into the Ethernet network.
Client
Bridge
Access Point
Bridge
192.168.0.34
192.168.0.34
LAN
192.168.0.72
192.168.0.72
Internet
245U-E Wireless Ethernet User Manual
Page 10 Dec 2011
Access Point vs Client
The Access Point unit acts as the ―wireless master‖ unit. The Access Point accepts and authorises links initiated but
client units, and controls the wireless communications.
Clients (Stations) are slave units and when connected to the
Access Point becomes transparent Ethernet link.
The first diagram shows a connection between two Ethernet
devices using 245U-E Ethernet modems. In this example one
245U-E is configured as an Access Point and the other as a
Client.
The second diagram shows an existing LAN being
extended using 245U-E’s. In this example, the Access
Point should be configured at the LAN end - although
the wireless link will still work if the Client is at the
LAN end.
An Access Point can connect to multiple Clients. In this
case, the Access Point should be the ―central‖ unit.
An Access Point could be used as a ―Repeater‖ unit to
connect two 245U-E Clients, which do not have direct
reliable radio paths.
There is no ―Special‖ repeater module, any 245U-E can
be a repeater and at the same time, can be connected to
an Ethernet devices or on a LAN
Multiple Access Points can be set-up in a ―mesh‖ network to provide multiple repeaters.
Client
Ethernet
Device
Access
Point
LAN
Ethernet
Device
Access
Point
Client
Ethernet
Device
Client
Client
Access Point
LAN
Client
Client
Access
Point
LAN
Client
Access
Point
Access
Point
Chapter One 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 11 Page 11
Client
Bridge
Access Point
Router
192.168.102.54
192.168.0.34
LAN A
192.168.102.17
192.168.102.53
LAN B
Bridge vs Router
Each 245U-E is configured with an IP address for the Ethernet side, and another for the wireless side.
A Bridge connects devices within the same Ethernet
network - for example, extending an existing Ethernet
LAN. For a Bridge, the IP address for the wireless side is
the same as the Ethernet side.
A Router connects devices on different LAN’s.
The IP addresses for the Ethernet and wireless sides are
different. In this example, the wireless link is part of LAN
A, with the Client unit acting as a Router between LAN A
and LAN B.
Alternately, the Access Point could be configured as a
Router - the wireless link is then part of LAN B.
If more than two routers are required within the same radio network, then routing rules may need to be configured
(refer section 3.18 ― Routing‖ for further details). There is no limit to the number of Bridges in the same
network - although there is a limit of 128 Client units linked to any one Access Point.
LAN C
Client
Router
Access Point
Bridge
LAN A
Client
Router
Client
Bridge
LAN B
192.168.0.34
192.168.109.40
192.168.102.17
192.168.0.72
192.168.0.34
192.168.0.72
192.168.0.73
192.168.0.74
Client
Router
Access Point
Bridge
192.168.0.34
192.168.0.34
LAN A
192.168.102.17
192.168.0.72
Client
Bridge
Access Point
Bridge
192.168.0.34
192.168.0.34
LAN
192.168.0.72
192.168.0.72
Internet
245U-E Wireless Ethernet User Manual
Page 12 Dec 2011
1.2 Getting Started Quickly
Most applications for the 245U-E require little configuration. The 245U-E has many sophisticated features,
however if you don’t require these features, this section will allow you to configure the units quickly.
First, read Chapter 2, ―Installation‖. The 245U-E requires an antenna and a power supply.
Power the 245U-E and make an Ethernet connection to your PC (for further information on how to do this,
refer to section 3.2 ―Configuring the Unit for the first time‖)
Set the 245U-E address settings as per section 3.2 ―Configuring the Unit for the first time‖
Save the configuration - the 245U-E is now ready to use.
Before installing the 245U-E, bench test the system. It is a lot easier to locate problems when the equipment is all
together.
There are other configuration settings, which may or may not improve the operation of the system. For details on
these settings, refer to section 3.0 ― Start-up‖.
Chapter Two 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 13 Page 13
Chapter 2 INSTALLATION
2.0 General
The 245U-E modules are housed in a rugged aluminium case, suitable for DIN-rail mounting. Terminals will
accept wires up to 2.5 mm2 (12 gauge) in size.
All connections to the module must be SELV (Safety Extra Low Voltage). Normal 110-250V
mains supply must not be connected to any terminal of the 245U-E module. Refer to Section 2.3
Power Supply.
Before installing a new system, it is preferable to bench test the complete system. Configuration problems are
easier to recognize when the system units are adjacent. Following installation, the most common problem is poor
communications caused by incorrectly installed antennas, or radio interference on the same channel, or the radio
path being inadequate. If the radio path is a problem (i.e. path too long, or obstructed), a higher performance
antennas or a higher mounting point for the antenna may rectify the problem. Alternately, use an intermediate
245U-E Module as a repeater.
The 245U-E Installation Guide provides an installation drawing appropriate to most applications. Further
information is detailed below.
Each 245U-E module should be effectively earthed via the "GND" terminal on the back of the module - this is to
ensure that the surge protection circuits inside are effective.
2.1 Antenna Installation
The 245U-E module will operate reliably over large distances however the achievable distances will vary with the
application, radio model, type and location of antennas, the degree of radio interference, and obstructions (such as
buildings or trees) to the radio path.
The maximum range achievable depends on the radio model, the regulated RF power permitted in your country,
and whether you use separate transmit and receive antennas.
If using a 245U-E-G (2.4GHz) with a single antenna, 10 km (6 miles) can be achieved in USA, Canada and
Australia (4W EIRP) and 2km in Europe (100mW EIRP).
If using a 245U-E-A (5 GHz) with a single antenna, 5 km (3 miles) can be achieved in USA, Canada and Australia
(1W EIRP) and 3km in Europe (500mW EIRP) however more care is needed in selecting antenna’s, coax as well as
radio paths need to be complete line of site (No obstruction what so ever).
To achieve the maximum transmission distance, the antennas should be raised above intermediate obstructions so
the radio path is true ―line of sight‖. The modules will operate reliably with some obstruction of the radio path,
although the reliable distance will be reduced. Obstructions which are close to either antenna will have more of a
blocking affect than obstructions in the middle of the radio path.
The 245U-E modules provide a diagnostic feature which displays the radio signal strength of transmissions (refer
Chapter 4 ―Diagnostics‖).
Line-of-sight paths are only necessary to obtain the maximum range. Obstructions will reduce the range, however
may not prevent a reliable path. A larger amount of obstruction can be tolerated for shorter distances. For short
distances, it is possible to mount the antennas inside buildings. An obstructed path requires testing to determine if
the path will be reliable - refer to section 0 of this manual.
Where it is not possible to achieve reliable communications between two 245U-E modules, then a third 245U-E
module may be used to receive the message and re-transmit it. This module is referred to as a repeater. This module
may also have a host device connected to it.
The 245U-E unit has two antenna connections at the top of the module, allowing for two antennas to be fitted to the
module if need be. By default the right connector labeled TX/RX is the main connection used to transmitter and
245U-E Wireless Ethernet User Manual
Page 14 Dec 2011
receiver. The left connector labeled ―RX‖ is not connected unless configured under the Advanced Radio
Configuration in Section 3.10. Each antenna port can be configured for TX only, RX only or Diversity (TX and
RX). Selection can be made by choosing one of the options from TX Antenna / RX Antenna on the Advanced
Radio Configuration page.
Note: When only one antenna is used, it must be connected to the TX/RX connector.
Antenna Diversity
One reason to use multi antennas is because of local radio licensing regulations. All countries have a limit on the
amount of transmitted power and radiated power from the antenna. In the US this is 400 millwatts transmit power
and 4 watts EIRP (Effective Isotropic Radiated Power). In a normal system if a high gain antenna is used it
improves the receive signal as well as boosting the transmit signal and possibly pushing it over the EIRP regulation
limit. Using Antenna diversity we can use two antennas, one for receive and the other for transmit. The receive
antenna has no regulatory limits as it does not radiate power so any gain antenna can be used. To calculate the
transmit antenna limit see the examples below.
Example
If using the 245U-E-G in the US the radio transmit power level will be 400mA which will allow up to 4 watts
EIRP, what this means is that we can add a gain of approximately 10dB (including cable loss) without infringing
the EIRP. This is calculated by using the general rule of thumb when working with dB and Power which is
doubling the power is a 3dB gain.
If using 10m (33ft) of Cellfoil coax cable (approximately 6dB of loss) and an 8 dBi Antenna this would equate to
approximately 2dB of gain, well below our 10dB limit.
If using 20m (66ft) of Cellfoil coax cable (approximately 12dB of loss) and an 18 dBi Antenna this would equate to
approximately 6dB of gain, which is also below our 10dB limit.
Another application where antenna diversity may be needed is in industrial plants and factories installations which
can suffer from ―multi-path fading‖ effects where multiple reflected radio signals adversely affect the signal
strength. In a ―static‖ installation, where the radio path is not changing, moving an antenna to the position of
maximum signal solves this problem. However where the radio path changes because the 245U-E is mounted on
moving equipment, or if there is moving equipment in the area, then the solution is to use two antennas. Because
the two connectors are separated, the RF signal at each connector will be different in the presence of multi-path
fading. The 245U-E unit will automatically select the higher RF signal provided RX diversity has been enabled on
radio Config page.
See Section 3.10 ―Advanced Radio Configuration‖ for details on configuring Antenna Diversity
Line-of-sight installations
In longer line-of-sight installations, the range may be increased by using a high gain antenna on the TX/RX
connector. However, the gain should not cause the effective radiated power (ERP) to exceed the permitted value. A
second higher gain antenna can be connected to the RX connector without affecting ERP - this will increase the
operating range provided any interference in the direction of the link is low.
Antennas
Antennas can be either connected directly to the module connectors or connected via 50 ohm coaxial cable (e.g.
RG58 Cellfoil or RG213) terminated with a male SMA coaxial connector. The higher the antenna is mounted, the
greater the transmission range will be, however as the length of coaxial cable increases so do cable losses.
The net gain of an antenna/cable configuration is the gain of the antenna (in dBi) less the loss in the coaxial cable
(in dB). The maximum net gain of the antenna/cable configuration connected to the TX/RX connector is 0dB in
Europe (100mW ERP). In USA, Canada and Australia (4W ERP), the maximum gain is 10dB for the 245U-E-400
or 16dB for the 245U-E-100.
There is no gain restriction for antennas connected to the RX connector.
(*) 20dB attenuator must be fitted if radio distance is less than 33ft (10m).
Chapter Two 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 15 Page 15
Stretch to elongate sealant tape
while wrapping over the connection
For proper UV protection Electrical
Tape should then be wrapped over
the Vulcanising Tape
Antenna
245U-E-G Gain (dBi)
245U-E-A Gain (dBi)
Dipole
2 dBi
6 dBi
Collinear
5 or 10 dBi
10 dBi
Directional
18 dBi
10 – 20 dBi
Cable Loss
dB per 30 m / 100 ft
dB per 30 m / 100 ft
RG58 Cellfoil
-17 dB
-24.5 dB
RG213
-16.2 dB
-28.6 dB
LDF4-50
-3.6 dB
-5.5 dB
The net gain of the antenna/cable configuration is determined by adding the antenna gain and the cable loss.
For example, if using the 245U-E-G a 10dBi antenna (7.8dBd) with 10 meters of Cellfoil (-5.6dB) has a net gain of
2.2dB (7.8dB – 5.6dB).
Installation tips
Connections between the antenna and coaxial cable should be
carefully taped to prevent ingress of moisture. Moisture ingress in
the coaxial cable is a common cause for problems with radio
systems, as it greatly increases the radio losses. We recommend that
the connection be taped, firstly with a layer of PVC Tape, then with
a vulcanizing tape such as ―3M 23 tape‖, and finally with another
layer of PVC UV Stabilized insulating tape. The first layer of tape
allows the joint to be easily inspected when trouble shooting as the
vulcanizing seal can be easily removed.
Where antennas are mounted on elevated masts, the masts should be
effectively earthed to avoid lightning surges. For high lightning risk
areas, surge suppression devices between the module and the
antenna are recommended. If the antenna is not already shielded
from lightning strike by an adjacent earthed structure, a lightning rod
may be installed above the antenna to provide shielding.
245U-E Wireless Ethernet User Manual
Page 16 Dec 2011
Dipole and Collinear antennas
A dipole or collinear antenna transmits the same
amount of radio power in all directions - as such
that are easy to install and use. The dipole antenna
with integral 15 ft (5m) cable does not require any
additional coaxial cable; however a cable must be
used with the collinear antennas.
Collinear and dipole antennas should be mounted
vertically, preferably 1 wavelength away (see
drawing below for distances) from a wall or mast
and at least 3ft (1m) from the radio module to
obtain maximum range.
Directional antennas.
Directional antennas can be
a Yagi antenna with a main beam and orthogonal elements, or
a directional radome, which is cylindrical in shape, or
a parabolic antenna.
A directional antenna provides high gain in the forward direction, but lower gain in
other directions. This may be used to compensate for coaxial cable loss for
installations with marginal radio path.
Yagi antennas should be installed with the main beam horizontal, pointing in the
forward direction. If the Yagi is transmitting to a vertically mounted omni-directional
antenna, then the Yagi elements should be vertical. If the Yagi is transmitting to
another Yagi, then the elements at each end of the wireless link need to in the same
plane (horizontal or vertical).
Directional radomes should be installed with the central beam horizontal and must be
pointed exactly in the direction of transmission to benefit from the gain of the
antenna. Parabolic antennas should be mounted as per the manufacturer’s instructions,
with the parabolic grid at the ―back‖ and the radiating element pointing in the
direction of the transmission.
Ensure that the antenna mounting bracket is well connected to ―ground/earth‖.
Directional
Antenna
45
o
Wavelengths
900 MHz = 330 mm (1')
2.4 GHz = 130 mm (5")
5 GHz = 60 mm (3")
COLINEAR
ANTENNA
MAST
IF GROUND CONDITIONS
ARE POOR, INSTALL MORE
THAN ONE STAKE
MODEM
SURGE
ARRESTOR
(OPTIONAL)
COAXIAL CABLE
WEATHERPROOF
CONNECTORS WITH
“3M 23” TAPE
STRESS RELIEF
LOOP
PROVIDE GOOD GROUND
CONNECTION TO MAST,
MODULE AND SURGE
ARRESTOR
GND
1 wavelength
Chapter Two 245U-E Wireless Ethernet
Man_245UE_V1.8.1.docx Page 17 Page 17
2.2 Power Supply
The 245U-E module can be powered from a 9 - 30VDC power supply. The power supply should be rated at 1 Amp.
The positive side of the supply must not be
connected to earth. The supply negative is
connected to the unit case internally. The DC
supply may be a floating supply or negatively
grounded.
The power requirements of the 245U-E unit
are shown in the following table
245U-E-G
245U-E-A
12VDC
24VDC
12VDC
24VDC
Quiescent
290mA
150mA
300mA
160mA
TX @100mW
310mA
170mA
370mA
190mA
TX @ 400mW
340mA
180mA
410mA
210mA
A Ground Terminal is provided on the back of the module. This Terminal should be connected to the Main Ground
point of the installation in order to provide efficient surge protection for the module (refer to the Installation
Diagram)
2.3 Serial Connections
RS232 Serial Port
The serial port is a 9 pin DB9 female and provides
for connection to a host device as well as a PC
terminal for configuration, field testing and for
factory testing. Communication is via standard
RS232 signals. The 245U-E is configured as DCE
equipment with the pinouts detailed below.
Hardware handshaking using the CTS/RTS lines is
provided. The CTS/RTS lines may be used to reflect
the status of the local unit’s input buffer. The 245UE does not support XON/XOFF.
Example cable drawings for connection to a DTE host (a PC) or another DCE hosts (or modem) are detailed above.
DCE HOST
DB9
MALE
MODEM
DB9
MALE
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
2
5
7
8
6
4
1
3
2
5
7
8
6
4
1
3
DCE HOSTMODEM
DB9
MALE
DB9
FEMALE
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
RD
TD
SG
RTS
CTS
DSR
DTR
DCD
2
5
7
8
6
4
1
3
2
5
7
8
6
4
1
3
+
_
B
A
-
+
COM
DIO
MODEM
9 – 30V
VDC
RS485
SUPPLY
245U-E Wireless Ethernet User Manual
Page 18 Dec 2011
DB9 Connector Pinouts
Pin
Name
Direction
Function
1
DCD
Out
Data carrier detect
2
RD
Out
Transmit Data – Serial Data Output (from DCE to DTE)
3
TD
In
Receive Data – Serial Data Input (from DTE to DCE)
4
DTR
In
Data Terminal Ready
5
SG
Signal Ground
6
DSR
Out
Data Set Ready - always high when unit is powered on.
7
RTS
In
Request to Send
8
CTS
Out
Clear to send
9
RI
Ring indicator
RS485 Serial Port
The RS485 port provides for communication between the 245U-E unit and its host device using a multi-drop cable.
Up to 32 devices may be connected in each multi-drop network.
As the RS485 communication medium is shared, only one of the units on the RS485 cable may send data at any
one time. Thus, communication protocols based on the RS-485 standard require some type of arbitration.
RS485 is a balanced, differential standard but it is recommended that shielded, twisted pair cable be used to
interconnect modules to reduce potential RFI. It is important to maintain the polarity of the two RS485 wires. An
RS485 network should be wired as indicated in the diagram below and terminated at each end of the network with a
120-ohm resistor. On-board 120-ohm resistors are provided and may be engaged by operating the single DIP
switch in the end plate next to the RS485 terminals. The DIP switch should be in the ―1‖ or ―on‖ position to
connect the resistor. If the module is not at one end of the RS485 cable, the switch should be off.
Shorter runs of 485 cable may not require the termination resistors to be enabled.
Wireless Ethernet
Modem
120 Ω
+
+ +
-
-
-
120 Ω
HOST HOST
DIP SWITCH
FOR 120Ω
DIO
SUPPLY
RS485
RS232
ETHERNET
DEFAULT DIP
SWITCH
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 19 19
2.4 Discrete (Digital) Input/Output
The 245U-E has one on-board discrete/digital I/O channel. This channel can act as either a discrete input or discrete
output. It can be monitored, or set remotely, or alternatively used to output a communications alarm status.
If used as an ―input‖, the I/O channel is suitable for voltage free contacts (such as mechanical switches) or NPN
transistor devices (such as electronic proximity switches). PNP transistor devices are not suitable. Contact wetting
current of approximately 5mA is provided to maintain reliable operation of driving relays.
The digital input is connected between the "DIO" terminal and common ―COM". The I/O circuit includes a LED
indicator which is lit GREEN when the digital input is active, that is, when the input circuit is closed. Provided the
resistance of the switching device is less than 200 ohms, the device will be able to activate the digital input.
The I/O channel may also be used as a discrete output. The digital outputs are transistor switched DC signals, FET
output to common rated at 30VDC 500 mA.
The output circuit is connected to the "DIO" terminal. The digital output circuit includes a LED
indicator which is lit RED when the digital output is active.
DIO
GND
MODEM
Voltage-free
contact input
V+
V-
_
+
DC
Load
Max 30VDC
0.5A
DIO
GND
MODEM
245U-E Wireless Ethernet User Manual
Page 20 Dec 2011
Chapter 3 OPERATION
3.0 Start-up
“Access Point” Start-up (245U-E-G)
When an Access Point (AP) unit starts up it checks to see if the Channel selection is set to ―Auto‖ and if so will
scan all available channels, pick the quietest then begin transmitting periodic messages, called beacons, if it is
configured with a fixed channel it will immediately begins sending beacons, on the configured channel.
Beacons include information that a Client may examine in order to identify if the Access Point is suitable for link
establishment. Clients will only attempt to establish a link with an Access Point whose beacon indicates a matching
SSID. Access Points do not initiate link establishment.
“Access Point” Start-up (245U-E-A)
If the modem is configured to use ―DFS‖ then it will behave slightly different, as it needs to comply with DFS
regulations.
When an Access Point starts up it will scan all available channels from the selected groups and then select the
quietest similar to the 245U-E-G. It will then go into a scan mode for 60 seconds where it listens for any Radar
signals.
If a radar signal is detected it will flag the channel as being unavailable (Channel will stay unavailable for 30
minutes) and then pick another random channel and go through the same scanning process until a radar free
channel becomes available.
“Client” Start-up
When a Client powers up, it scans for beacons from Access Points. While a link is not established, the Client
cyclically scans all available channels for a suitable Access Point. The Client will attempt to establish a link with an
Access Point only if it has matching SSID, Encryption method, etc. and other compatible capabilities as indicated
by the beacon. If more than one suitable Access Point is discovered, the client will attempt to establish a link with
the Access Point that has the strongest radio signal.
Link Establishment
Once a Client identifies a suitable Access Point for link establishment it attempts to establish a link using a twostep process – ―Authentication‖ and ―Association‖. During Authentication the Client and Access Point check if
their configurations permit them to establish a link. Once the Client has been authenticated, it will then request an
Association to establish a link.
Status of the wireless link is indicated via the TX/LINK LED. For an Access Point, the TX/LINK LED will be OFF
while no links have been established. Once one or more links have been established, the TX/LINK LED is on
GREEN. For a Client, the Link LED will reflect the connection status to an Access Point. Link status is also
displayed on the ―Connectivity‖ page of the web interface.
After the link is established, data may be transferred in both directions. The Access Point will act as a master-unit
and will control the flow of data to the Clients linked to it. Clients can only transmit data to the AP to which they
are connected. When a Client transfers data to another Client, it first transmits the data to the AP, which then
forwards the data to the destined Client.
Presence of a “link” does not mean that the connected unit is authorized to communicate over
radio. If the encryption keys are incorrect between units in the same system, or a dissimilar
encryption scheme is configured, the LINK led will light, however data cannot be passed over the
wireless network.
A maximum of 127 Clients may be linked to an Access Point.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 21 21
How a Link connection is lost
The Access Point refreshes the link status with a Client every time a message is received from that Client. If
nothing is received from a Client for a period of 120 seconds, the Access Point sends a ―link-check‖ message. If
there is no response to the link-check a De-authenticate message is sent and the link is dropped.
A Client monitors beacon messages from an Access Point to determine whether the link is still present. If the Client
can no longer receive beacons from the Access Point it assumes the AP is out-of-range and the link is dropped.
Whenever a Client is not connected to an AP, it will cyclically scan all available channels for a suitable AP.
Roaming Clients
Clients can roam within a system however if the link to the Access Point fails or the radio signal level becomes too
weak it will scan for beacons and connect to an Access Point (provided the SSID and any Encryption methods,
keys, etc are compatible). If there are multiple Access Points it will select the connection with the best signal level.
This functionality permits a client to have mobility whilst maintaining a link with the most suitable AP.
LED Indication
The following table details the status of the indicating LEDs on the front panel under normal operating conditions.
LED Indicator
Condition
Meaning
OK
GREEN
Normal Operation
OK
Flashing RED / GREEN
Module Boot Sequence
Radio RX
GREEN flash
Radio receiving data (Good Signal Strength)
Radio RX
RED flash
Radio receiving data (Low Signal strength)
TX/LINK
GREEN
Radio Connection Established
TX/LINK
RED Flash
Radio Transmitting
RS-232
GREEN flash
Data sent from RS-232 Serial Port
RS-232
RED flash
Data received to RS-232 Serial Port
LAN
ON
Link Established on Ethernet port
LAN
Flash
Activity on Ethernet port.
RS-485
GREEN flash
Data sent from RS-485 Serial Port
RS-485
RED flash
Data received to RS-485 Serial Port
DIO
GREEN
Digital Input is grounded.
DIO
RED
Digital Output is active
DIO
Off
Digital Output OFF and Input is open circuit.
The Ethernet RJ45 port incorporates two indication LEDs. The LINK LED comes on when there is a connection on
the Ethernet port, and will blink off briefly when activity is detected on the Ethernet Port. The 100MB LED
indicates that the connection is at 100 MBit/Sec. The 100MB LED will be off for 10MB/Sec connection.
Other conditions indicating a fault are described in Chapter 4 ―DIAGNOSTICS‖.
3.1 Selecting a Channel
802.11b/g (2.4GHz)
The 245U-E-G conforms to the IEEE 802.11b/g Wireless LAN specification. The 245U-E-G supports 13 x 20MHz,
12 x 10MHz and 13 x 5MHz radio channels in the 2412MHz to 2482MHz frequency range. Channels are country
or region specific. Please check your local regulatory body for compliance and channel selection.
You can see from the diagram below there are a limited number of channels available in the 2.4 GHz frequency
range. Care must be taken when selecting an operating channel as some of the channels overlap.
245U-E Wireless Ethernet User Manual
Page 22 Dec 2011
The 20M channels have a separation of 5MHz which means there is some overlap into the
next channel, i.e. channel 1 will overlap into channel 2, 3 and 4; channel 6 will overlap into
channels 3, 4, 5, 7, 8 and 9. If complete separation is required then you can use channels 1, 6
and 11 without any interference between the channels.
The 10M channels are also separated by 5MHz and overlap the adjacent channels by 5MHz forward and backward,
i.e. Channel 41 will overlap with channel 42; channel 46 will overlap with channel 45 and 47.
Lastly the 5MHz channels are separated by 5MHz and do not overlap at all so you can operate all 13 channels at
the same time with minimal interference with the adjacent channel.
Only one of these channels is used at a time and is configured at the Access Point, The Access Point then uses this
channel to send out beacon transmissions and connections.
Clients scan all channels for a suitable Access Point and then adopt the same channel as the AP when a connection
is established.
20MHz (7)
5MHz (23)
10MHz (41)
20MHz (2)
20MHz (1) 20MHz (6) 20MHz (11)
20MHz (8)20MHz (3)
20MHz (9)20MHz (4)
20MHz (10)20MHz (5)
5MHz (22)5MHz (21) 5MHz (24)
5MHz (33)*
5MHz (27)5MHz (26)5MHz (25) 5MHz (28) 5MHz (31)5MHz (30)5MHz (29)
5MHz (32)*
10MHz (43) 10MHz (45) 10MHz (47) 10MHz (49) 10MHz (51)
10MHz (42) 10MHz (44) 10MHz (46) 10MHz (48) 10MHz (52)*
40MHz Turbo (6)
10MHz (50)
20MHz (12)*
20MHz (13) *
Frequency Band
(Channel Number)
2412 2417 2432 2442 2452 24622422 2427 2437 2447 2457 2467
2407
Frequency
2482 MHz
2472 2477
* Note:
Channels not
available in the USA
The following diagram shows the RF energy distribution for the 802.11b/g transmission:
On the 20MHz channel (Green) most of the energy is transmitted within the channel however some of the energy is
transmitted on the channels either side therefore causing interference on the these channels. The 10MHz channels
(Orange) are similar with half of the energy overlapping into the next channel however you can configure up to 6 x
non interfering channel at the one time. Lastly the 5 MHz channels (Blue) do not overlap and so all 13 channels can
be used at the same time.
There is also a single 40MHz Channel (Purple) which takes up over half of the full 2.4 GHz band and so it much
more susceptible to interference from other channels.
If there is more than one 802.11 AP within the same wireless range, then it is important that the AP’s are on
channels as far apart as possible.
If there are two 20MHz channel AP’s, then set them to channel 1 and 11. If there are three, set them to 1, 6, and
11.
11
6
1
11
1
6
11
1
6
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 23 23
40 MHz Turbo Channel
20 MHz Channel
10 MHz Channel
5 MHz Channel
* Note:
Channels not
available in the USA
52*51
5049
4847
46454443
42
41
21
22
23 24 25 26 27 28 29 30 31 32* 33*
Channels
2422 2432 2442 2452 2462 MHz2412 2427 2437 2447 24572417 2467 2472
3 5 7 9 111 4 6 8 102 12 * 13 *
802.11a (5GHz)
The 245U-E-A utilizes frequency bands within the range of 5.15 GHz and 5.825 GHz. This is broken into 4 distinct
U-NII bands and each region (EU, US, AUS, NZ, etc) have their own power and operational constraints, see
Appendix C for more details.
The example below shows the US power and operational constraints
―Group 1‖: 5.15-5.25GHz @ 50mW
―Group 2‖: 5.25-5.35GHz @ 250mW to 1 Watt
―Group 3‖: 5.47-5.725 GHz @ 250mW to 1 Watt
―Group 4‖: 5.725-5.825GHz @ 1Watt
Each frequency band has certain limitations on the amount of radiated power that it can output as well as whether
the band uses what is called ―Dynamic Frequency Selection‖ (DFS), explained below.
Dynamic Frequency Selection (DFS)
Because of the push within the 802.11a market to open up new spectrum for unlicensed radio a mechanism called
―Dynamic Frequency Selection‖ needed to be developed so that the 802.11 Wi-Fi could coexist with existing
military and telecommunication radar systems.
Access points with 5GHz radios comply with regulations that require radio devices to use Dynamic Frequency
Selection (DFS), which can detect radar signals and avoid interfering with them by automatically scanning and then
selecting another channel or band.
When DFS is enabled, the Access Point (master device) goes through the following steps:
1. The master device that initiates communications selects a channel and monitors that channel for potential
radar interference for a minimum listening time of 60sec (channel availability check time). No
transmissions can occur during this period.
5 GHz Channels
5220 5260 5300 5500 55405180 5240 5280 5320 55205200 5600 5640 5680 5745 5785
MHz
5560 5620 5660 5700 57655580 5805 5825
44 52 60 100 10836 48 56 64 10440 120 128 136 149 157112 124 132 140 153116 165161
20MHz
54Mbps
40MHz
108Mbps
Turbo Channels
152 & 160
Turbo Channel 41
Group 1
5.15-5.25 GHz
Group 2
5.25-5.35 GHz
Group 3
5.47-5.725 GHz
Group 4
5.725-5.825 GHz
245U-E Wireless Ethernet User Manual
Page 24 Dec 2011
2. If interference is detected then the system has to go and select another channel and repeat the channel
availability check on the new channel (the original channel is added to a list of channels with radar).
3. Once a channel has been selected and passes the channel availability check the network starts to use that
channel.
4. While using the channel the network’s master device continuously monitors for potential interference from
a radar source (this is referred to as ―in-service monitoring‖). If interference is detected then the network
master device issues commands to all other in-network devices to cease transmissions. The channel is
added to the list of channels with radar.
5. The master device then selects a new channel (one that is not on the radar list).
6. A channel that has been flagged as containing a radar signal, either by a channel availability check or by
in-service monitoring, is subject to a 30 min non-occupancy period where it cannot be used by the device
in order to protect scanning radars. The channel on the radar list will be purged once the non-occupancy
period has elapsed for that channel.
3.2 Configuring the Unit for the first time
The 245U-E has a built-in web server, containing web pages for analyzing and modifying the module’s
configuration. The configuration can be accessed using Microsoft® Internet Explorer version 7 or greater. This
program is shipped with Microsoft Windows or may be obtained freely via the Microsoft® website. If using other
browsers they must be fully compliant with IE7 SSL security.
Note: Microsoft Internet Explorer Version 6 will not load web pages due to a compatibility issue
between IE6 and SSL-security web sites.
Default Configuration
The default factory configuration of the 245U-E is
Client/Bridge/
IP address192.168.0.1XX, where XX is the last two digits of the serial number (the default IP address is
shown on the printed label on the back of the module)
Netmask 255.255.255.0
Username is ―user‖ and the default password is ―user‖
The 245U-E will temporarily load some factory-default settings if powered up with the Factory Default switch (on
the end-plate of the module) in SETUP position. When in SETUP mode, wireless operation is disabled. The
previous configuration remains stored in non-volatile memory and will only change if a configuration parameter is
modified and the change saved.
Do not forget to set the switch back to the RUN position and cycle power at the conclusion of
configuration for resumption of normal operation.
Accessing Configuration for the first time
Because the Default IP address is in the range 192.168.0.XXX it may not connect to you network or PC so there are
two methods for accessing the configuration for the first time.
Method 1 - Change your computer settings so that the configuring PC is on the same network as the 245U-E with
factory default settings. This is the preferred method and is much less complicated than the second method. You
will need a ―straight-through‖ Ethernet cable between the PC Ethernet port and the 245U-E. The factory default
Ethernet address for the 245U-E is 192.168.0.1XX where XX are the last two digits of the serial number (check the
label on the back of the module).
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 25 25
Method 2 - Requires temporarily changing the IP address in the 245U-E via an RS232 connection such that it is
accessible on your network without having to change your PC network settings. When connected you can change
the modem network settings to match that of your network.
Method 1 - Set PC to same network as 245U-E
Connect the Ethernet cable between unit and the PC configuring the module.
Set the Factory Default Switch to the SETUP position. This will
always start the 245U-E with Ethernet IP address 192.168.0.1XX,
subnet mask 255.255.255.0, gateway IP 192.168.0.1 and the radio
disabled. Do not forget to set the switch back to the RUN position
and restart the module at the conclusion of configuration for
resumption of normal operation.
Power up the 245U-E module.
Open ―Network Settings‖ on your PC under Control Panel. The
following description is for Windows XP - earlier Windows
operating systems have similar settings.
Open ―Properties‖ of Local Area Connection.
Select Internet Protocol (TCP/IP) and click on Properties.
On the General tab enter IP address 192.168.0.1, Subnet mask 255.255.255.0 and press ―OK‖
Open Internet Explorer and ensure that settings will allow you to
connect to the IP address selected. If the PC uses a proxy server,
ensure that Internet Explorer will bypass the Proxy Server for local
addresses.
This option may be modified by opening Tools -> Internet Options
-> Connections Tab -> LAN Settings->Proxy Server -> bypass
proxy for local addresses.
Enter the default IP address for the 245U-E https://192.168.0.1XX
where XX is the last two digits of the serial number.
Enter the username ―user‖ and default password ―user‖.
245U-E Wireless Ethernet User Manual
Page 26 Dec 2011
Figure 1 – Welcome Webpage
To resume normal configured operation when Configuration is complete, switch Factory Default dip-switch on the
245U-E to RUN and cycle power.
Note: Security Certificates. Configuration of the 245U-E uses an encrypted link (https). The security certificate
used by the 245U-E is issued by ELPRO and matches the IP address 192.168.0.100.
When you first connect to the 245U-E, your web browser will issue a warning that ELPRO is not a trusted
authority. Ignore this warning and proceed to the configuration web page. To avoid seeing this warning in future,
you can install the certificate into your browser.
Internet Explorer 7 has an additional address check on security certificates. Unless the 245U-E has the address
192.168.0.100, when you first connect to the 245U-E, Internet Explorer 7 will issue a warning about mismatched
security certificate address. You can turn off this behaviour in IE7 by selecting
―Tools > Internet Options > Advanced > Security > Warn about certificate address mismatch*‖
Method 2 - Set 245U-E Network address to match the local network
For this method you will need to determine what IP address, Gateway address, and netmask to assign to the 245U-E
so that it appears on your network. Ask your system administrator if you don’t know the correct settings for your
network. E.g.
The default IP address of the 245U-E modem is 192.168.0.1 and the network you wish to connect to is on
10.10.0.X (PC is on 10.10.0.5)
Once you have determined the correct settings for your network, you need to connect to the modem’s RS-232 serial
port using a straight through serial cable and a terminal package such as HyperTerminal set to 115,200 baud. 8 data
bits, 1 stop bit, no Parity.
Open HyperTerminal and monitor communications
Set the SETUP/RUN switch to the SETUP position, and connect power to the modem.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 27 27
Observe HyperTerminal and when you see the Elpro Dragon screen (see below) press <Enter> to get the
following prompt ―#‖
Type the following ―ifconfig‖ and it will show the configuration of the Ethernet port and from this you
will be able to see what the IP address is, e.g.
eth0 Link encap:Ethernet HWaddr 00:12:AF:FF:FF:FF
inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU: 1500 Metric: 1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:256
Temporarily change the IP address to something that will enable connection to your local network. E.g
type ―ifconfig eth0 10.10.0.6 netmask 255.255.255.0‖ only add the netmask if the netmask is anything
other than the standard 255.255.255.0
IP address should now be changed and you can check by typing ―ifconfig‖ again. Note these changes are
only temporary and if the module is reset they will go back to the normal default (192.168.0.XXX).
Open Internet Explorer and ensure that settings will allow you to connect to the IP address selected. If the
PC uses a proxy server, ensure that Internet Explorer will bypass the Proxy Server for local addresses.
This option may be modified by opening Tools -> Internet Options -> Connections Tab -> LAN Settings>Proxy Server -> bypass proxy for local addresses.
Enter the IP address for the 245U-E into the Internet Explorer Address bar e.g. http://10.10.0.6 which is
the IP address you temporarily configured with the ifconfig command.
Enter the username ―user‖ and default password ―user‖.
You should now be connected to the main index page on the modem as per figure 1 above.
From here connect to the Network page and change the Ethernet Interface and Wireless Interface IP
addresses to 10.10.0.6. Switch the RUN/SETUP switch back to RUN and press ―Save Changes and Reset‖
button.
Note: As the modem can be setup numerous ways, e.g. Bridge, Router, etc this setup will allow the modem to
appear on the 10.10.0.X network. Any other configuration changes can be done after this initial connection (see the
following sections on configuration)
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245U-E Wireless Ethernet User Manual
Page 28 Dec 2011
3.3 Quick Start Configuration
The 245U-E has a Quick Start Configuration option, which will cover most important parameters that are needed to
get an initial connection. This is the first stage of the module configuration. For most applications, no further
configuration is required. For more advanced applications, the other parameters can be changed via the normal
configuration pages after the Quick Start configuration has been saved.
Select ―Quick Start‖ from the Main Menu and then you need to select the following parameters:
Quick Start Configuration
Operating Mode
Access Point or Client. Bridge operation is assumed - for Router selection, go to the
Network page after Quick Start
Default Gateway
This is the address that the device will use to forward messages to remote hosts that
are not connected to any of the local bridged network (Ethernet or Wireless)
IP Address / Subnet Mask
IP Address and Subnet Mask for your application.
System Address (ESSID)
The system address is a text string 1 to 31 characters in length used to identifies your
system
Radio Encryption
Radio encryption selection - None, WPA-PSK (TKIP), WPA-PSK (AES) or
WPA2 – refer to section 3.7 ―Security Menu‖ if WEP or Enterprise encryption is
required.
WPA Passphrase
128bit Encryption keys are internally generated based on the Passphrase and System
Address (ESSID). The Passphrase must be between 8 and 63 characters in length,
and must be the same for all 245U-E units in the same system.
The default settings will be shown. If your system is connecting individual devices which are not connected to an
existing Ethernet LAN, then you can use the factory default IP values. If you are connecting to an existing LAN,
then you need to change the IP addresses to match your LAN addresses.
After configuring, select ―Save to Flash and Reset‖.
Radio Data Rate and Channel will be set to Auto, Radio Transmit Power will be set to maximum and any previous
configuration of unrelated parameters will not be modified, and will still apply.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 29 29
3.4 Network Configuration
You can view or modify Ethernet network parameters by selecting the ―Network‖ menu. When prompted for
username and password, enter ―user‖ as the username, and ―user‖ as the password in the password field (This is the
factory default – See section 3.23 ―Module Information Configuration‖ to change). If you have forgotten the IP
address or password, the Factory Default switch may be used to access the existing configuration. Refer to previous
section above for this procedure.
The Network Configuration page allows configuration of parameters related to the wired and wireless Ethernet
interfaces. In general, IP address selection will be dependent upon the connected wired Ethernet device(s) – before
connecting to an existing LAN consult the network administrator.
A system of 245U-E’s must have at least one Access Point configured as a master with one or more Clients. All
245U-E’s should be given the same System Address (ESSID) and Radio Encryption settings. For further
information and examples on wireless network topologies refer section 1.1 ―Network Topology‖ above.
The 245U-E supports several different radio encryption schemes. If utilising any form of encryption, all modules in
the system that communicate with each other will need the same encryption method and encryption keys.
WEP (Wired Equivalent Privacy) encryption is the weakest encryption method, defined by the original IEEE802.11
standard and uses a 40bit or 104bit key with a 24bit initialization vector to give a 64bit and 128bit WEP encryption
level. WEP is not considered an effective security scheme, and should only be used if it is necessary to interoperate
with other equipment which does not support more modern encryption methods.
WPA (Wi-Fi Protected Access) is a subset of the IEEE802.11i Security Enhancements specification.
The 245U-E supports WPA-1 TKIP and WPA-2 AES using a Pre-Shared Key (PSK).
TKIP (Temporal Key Integrity Protocol) enhances WEP by using 128-bit encryption plus separate 64bit
Tx and Rx MIC (Message Integrity Check) keys.
AES (Advanced Encryption Standard), the most secure encryption method, is also based on 128-bit
encryption key and is the recommended encryption method in most applications.
245U-E Wireless Ethernet User Manual
Page 30 Dec 2011
WPA-Enterprise (802.1x) removes the need to manage the Pre-shared Key (PSK) by using an external server to
provide client authentication. Clients that are not authorized will be prevented from accessing the network. Once a
client has provided the correct authentication credentials, access is permitted and data encryption keys are
established, similar to WPA-PSK. Fine-grain (user level) access control can be achieved using this method.
An 802.1x capable RADIUS server may already be deployed in a large scale network environment. The 245U-E
can make use of this server reducing replication of user authentication information.
In a typical WPA-enterprise setup, the 245U-E Access point acts as Authenticator, controlling access to the
network. Wireless clients (245U-E’s, Laptops or other devices) act as Supplicants, requesting access to the
network. The Authenticator communicates with an authentication (RADIUS) server on the Ethernet network to
verify Supplicant identity. When a Supplicant requests access, it sends an access request to the Authenticator,
which passes an authentication request to the external authentication server. When the user credentials of the
Supplicant are verified, the Authenticator enables network access for the Supplicant, data encryption keys are
established and network traffic can pass.
Configuration of WPA-Enterprise differs when the unit is configured as an Access point (Authenticator) or Client
(Supplicant). If WDS interfaces are used, it is possible for one 245U-E to act as both an Authenticator and a
Supplicant, however in this situation, only one set of user credentials can be entered for all Supplicants.
After changes are made to Network Configuration, it is important to save the configuration by selecting ―Save
Changes‖ or by selecting ―Save Changes and Reset‖.
Network Settings Webpage Fields
Operating Mode
Used to select Access Point (Infrastructure), Client (Infrastructure).
By default this is set to Client.
Device Mode
Used to select Bridge or Router mode.
By default this is set to Bridge.
Bridge STP
Checking this box enables Spanning Tree protocol in bridged networks. See to section
3.5 ―Spanning Tree Algorithm‖‖ for more details
Bridge Priority
This is the priority associated with the Spanning tree protocol. Use lower numbers to
move this station towards the root of the Spanning Tree, and use higher number here to
move the station towards the leaves of the tree.
Default Gateway
This is the address that the device will use to forward messages to remote hosts that are
not connected to any of the local bridged network (Ethernet or Wireless). This is only
required if the wired LAN has a Gateway unit which connects to devices beyond the
LAN - for example, Internet access. If there is no Gateway on the LAN, set to the same
address as the Access Point - that is, the ―Ethernet IP Address‖ below. Refer to section
3.18― Routing ‖ for more information.
Obtain IP Address
Automatically
Checking this item enables DHCP client on the 245U-E. A DHCP client requests its IP
address from a DHCP server which assigns the IP Address automatically. For more
information, refer to section 3.21 ― DHCP Server Configuration‖, Default is
unchecked.
MAC Address
This is the unique hardware address of the 245U-E and is assigned in the Factory. The
245U-E has two MAC addresses, one for each interface (Ethernet and Wireless) The
Ethernet MAC is the primary MAC Address.
IP Address
The IP address of the 245U-E on its wired (Ethernet Interface) port and wireless
(Wireless Interface) port. This should be set to the IP address you require. If the device
mode is set to bridge, then the wired and wireless ports will have the same IP address.
IP Subnet Mask
The IP network mask of the 245U-E on its wired (Ethernet Interface) port and wireless
(Wireless Interface) port. This should be set to appropriate subnet mask for your system
(Typically 255.255.255.0).
System Address (ESSID)
A 245U-E wireless network comprises modules with the same "system address‖. Only
modules with the same system address will communicate with each other. The system
address is a text string 1 to 31 characters in length. Select a text string which identifies
your system.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 31 31
Desired BSSID
To force a client/station to always connect to the same Access Point enter the MAC
address of that Access Point in the Desired BSSID field
(Note that the ESSID of the Access Point must also match the configured ESSID of the
client).
Radio Encryption
Select the desired radio Encryption level.
Encryption key, passphrase, etc is entered on the ―Security Menu‖ (See section below
for details)
Save Changes
Save changes to non-volatile memory. The module will need to be restarted before the
changes take effect.
Save Changes and Reset.
Save settings to non-volatile memory, and reboot 245U-E. Once the module has
completed the reboot sequence, all changes are in effect.
3.5 Spanning Tree Algorithm
The bridge ―Spanning Tree Protocol‖ function was introduced to handle network loops and provide redundant paths
in networks. To enable tick the STP box on any ―WDS Connections‖ you have configured on the ―Repeaters‖
configuration page.
For example, consider this network with a redundant wireless link. If the bridge Spanning Tree Protocol is enabled,
one of the two wireless links will be disabled - that is, all wireless data will be transferred by one link only. If the
active link fails, the other link will automatically start transferring the wireless data.
The Spanning Tree Protocol implemented is IEEE 802.1d compatible. The algorithm forms a loop-free network by
blocking traffic between redundant links in the network. These blocked links are placed in a standby condition, and
may be automatically enabled to repair the network if another link is lost. The Spanning Tree Algorithm maintains
a single path between all nodes in a network, by forming a tree-like structure. The Bridge Priority determines where
the node sits in the tree. A Bridge configured with the lowest priority (0) will become the root node in the network,
and will direct traffic between each of its branches. The root node is typically the unit that handles the majority of
traffic in the network. The 245U-E is configured with a Bridge Priority of 32768 by default. The intention is to
reduce traffic that the 245U-E must handle, by placing it at the branch level in the network tree. As a branch, the
245U-E needs only pass traffic to devices that are its ―leaves‖.
There is some overhead in maintaining a network utilizing the Spanning Tree Algorithm. Users wishing to increase
their throughput, at the expense of redundancy should disable Spanning Tree. The Spanning Tree Protocol can be
configured on the Repeaters configuration page.
Client Bridge
Client Bridge
Access Point
Bridge
Access Point
Bridge
245U-E Wireless Ethernet User Manual
Page 32 Dec 2011
3.6 Compatibility
3 Address (Layer 3 Bridge) & 4 Address Mode
What Addresses are in a wireless Ethernet data frame?
There are two different Wi-Fi communication ―modes‖, 3 Address and 4 Address Modes. Each mode has a slightly
different way that it addresses the data frames to other devices on the network.
In 3 Address Mode the addressing is made up of a Destination Address (DA), a Source Address (SA), and a BSSID
(MAC Address of the Access Point)
In 4 Address Mode the addressing is made of a Destination Address (DA), a Source Address (SA), a Radio
Transmit Address (RTA), and a Radio Receive Address (RRA).
Packets between AP and Client
Communications between Access Points and Client is generally done using 3 Address Mode because there are only
3 addresses within the communication path as indicated in the path from the Laptop to Station #1 in the diagram
below.
If the Laptop wishes to communicate to Station #1 the DA will be Station #1, the SA will be the Laptop and the
BSSID will be the AP’s MAC Address hence the
3 Address Mode.
The example shows the Laptop may need to
communicate to the Ethernet Device connected to
Station #2.
You can see that there is now a fourth address that
cannot be addressed using the 3 Address Mode of
communications.
i.e. Laptop, AP, Station #2 and Ethernet Device.
The example shows the Access Point and the
Station as both being 245U-E modules which will
happily communicate as both support 4 Address Mode.
However, there are some instances where a third Party Access Point may not be able to communicate using 4
Address Mode to a Client (Sta).
There are only a couple of ways around this sort of situation.
Changing Station #2 to a Router, however this may mean that Station #2 and the Ethernet Device will use
a different network address scheme which may be inconvenient and will require more setup.
Configure the Access Point to communicate 4 Address Mode
If choosing the later this will only be possible if the Station and the AP support 4 Address Mode, some third Party
AP’s do not.
240U-E Compatibility
245U-E-G modules can communicate with ELPRO 240U-E Ethernet modems however only in certain modes. The
following table shows compatible configurations.
If communicating with ELPRO 240U-E Ethernet modems the 240U-E’s need to be configured with WDS (4
address mode), not the default ―3-address mode‖ and the 240U-E AP’s cannot be auto connect to any WDS AP.
Station #1
Station #2
Laptop #1
Access
Point
Ethernet
Device
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 33 33
Notes:
1. Connection only if the 245U-E-G is configured with a virtual Station (Client) which in turn connects to the
240U-E Access Point.
2. Connection indication in the ―connectivity‖ pages however it is not a true connection (see ―3 Address & 4
Address Modes‖ above).
3.7 Security Menu
Select the Radio Encryption level from the drop down menu on the Main index page and then press the ―Save
Changes‖ button.
Available encryption levels are - ―None‖, ―WEP (64-bit)‖, ―WEP (128-bit)‖, ―WPA-PSK (TKIP)‖,
―WPA-PSK (AES)‖, ―WPA2-PSK (AES)‖, ―WPA-PSK/ WPA2-PSK‖ & WPA-Enterprise. The default setting is
―None‖.
You will now need to go to the ―Security Menu‖ and enter in the encryption keys (WEP), passphrase (WPA), etc.
245U-E-G
AP
245U-E-G
Sta
240U-E AP
(4Add)
240U-E CL
(4Add)
240U-E AP
(3Add)
240U-E CL
(3Add)
245U-E-G AP
Y
Y
Y (Note 1)
Y N Y
245U-E-G Sta
Y Y Y
N/A
N (Note 2)
N/A
245U-E Wireless Ethernet User Manual
Page 34 Dec 2011
WEP (64 bit) & (128 bit)
Encryption Keys 1 to 4
These are the keys used to encrypt radio data to protect
data from unwanted eavesdroppers when WEP
Encryption is selected. These keys should be the same
for all 245U-E units in the same system.
Authentication Mode =Open/Shared
One of the four keys may be selected as the default key,
and is used to encrypt transmitted messages from the
configured unit. A 245U-E can receive and decrypt a
message from a module that has a different default key
index as long as each module has the same key
configured at the same index.
WEP keys must be entered as pairs of hexadecimal
digits separated by colons. Hexadecimal digits are in the
range 0...9 and A...F.
64bit WEP requires 10 Hexadecimal digits, and 128bit WEP
requires 26 Hexadecimal digits. For example, 12:AB:EF:00:56. for
64bit encryption, and 12:AB:EF:00:56:15:6B:E4:30:C8:05:F0:8D
for 128bit encryption
Encryption keys must not be all zeros, i.e. 00:00:00:00:00
WEP Open Authentication Mode
Station sends an authentication request to the Access
Point
Access Point then authenticates the Station
Station then associates with the Access Point and joins
the network.
WEP Shares Authentication Mode
Station sends an authentication request to the Access
Point
Access Point then sends a text based message to the
Station
Station uses its own WEP key to encrypt the text based
message and sends it back to the Access Point.
Access Point then decrypts the message using its on
WEP key and if it matches authenticates the Station.
Station then associates with the Access Point and joins
the network.
WPA / WPA2
When WPA Encryption is selected, 128bit Encryption
keys are internally generated based on the Passphrase
and System Address (ESSID). The Passphrase must be
between 8 and 63 characters in length, and the
Passphrase must be the same for all 245U-E units in the
same system.
For optimal security a passphrase consisting of a
combination of letters and numbers (i.e. not just a
simple word or phrase) as well as upper and lower case.
E.g. ―WiReLeSs TeChNoLoGy 2010‖
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 35 35
WPA Enterprise - Supplicant
Configuration
Username / Password:
user credentials that match a valid user on the RADIUS
server.
Enable Debug:
Must only be used during commissioning and only if
requested by ELPRO Support. This must be disabled for
normal operation.
Trusted CA certificate upload
Upload the certificate of the issuer of the RADIUS
server’s certificate. This enables the Supplicant to verify
the identity of the RADIUS server during the
authentication process.
Supported EAP method - PEAP / MSCHAPv2
Certificate Verification result:
Once a certificate has been loaded, this text box will
contain validation information for the certificate. If this
text is blank or contains errors, the certificate is invalid.
Trusted CA Certificate Contents:
Displays the contents of the loaded certificate.
WPA Enterprise - Authenticator
Configuration
RADIUS Server IP Address/Port/shared secret:
Connection information for the RADIUS Authentication
Server.
Supplicant Re-authenticate Period:
Sets the maximum time at which the Supplicant must
re-authenticate. This parameter determines maximum
time a client will still have access to the network after its
user credentials have been revoked.
Enable Debug:
Must only be used during commissioning and only if
requested by ELPRO Support. This must be disabled for
normal operation.
245U-E Wireless Ethernet User Manual
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3.8 Normal Operation
After addresses are configured, the units are ready for operation.
Refer to section 1 for an explanation on the operation of a Bridge and Router.
Transparent Bridge Operation
A bridge connects several Ethernet networks together, and makes them appear as a single Ethernet network to
higher protocol layers.
By default, the 245U-E is configured as a transparent bridge. When a transparent bridge is started, it learns the
location of other devices by monitoring the source address of all incoming traffic. Initially it forwards all traffic
between the wired Ethernet port and the wireless port, however by keeping a list of devices heard on each port, the
transparent bridge can decide which traffic must be forwarded between ports - it will only transfer a message from
the wired port to the wireless port if it is required.
A bridge will forward all Broadcast traffic between the wired and wireless ports. If the wired network is busy with
broadcast traffic, the radio network on the 245U-E can be unnecessarily overburdened. Use filtering to reduce
broadcast traffic sent over the radio. Refer Section 3.19 ― Filtering‖ for how to configure a filter.
By default, a transparent bridge does not handle loops within the network. There must be a single path to each
device on the network. Loops in the network will cause the same data to be continually passed around that loop.
Redundant wireless links may be set up by enabling the bridge Spanning Tree Protocol (see section 3.5 ―Spanning
Tree Algorithm‖ for more details).
Router Operation
A router joins separate IP sub-networks together. The router has different IP addresses on its wired and wireless
ports, reflecting the different IP addresses of the separate Ethernet networks. All of the devices in these separate
networks identify the router by IP address as their gateway to the other network. When devices on one network
wish to communicate with devices on the other network, they direct their packets at the router for forwarding.
As the router has an IP address on each of the networks it joins, it inherently knows the packet identity. If the traffic
directed at the router cannot be identified for any of the networks to which it is connected, the router must consult
its routing rules as to where to direct the traffic to. For details on configuring routing rules, see section 3.18 ―
Routing ‖.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 37 37
3.9 Radio Configuration
The 245U-E can be configured for different radio transmission rates. A reduction in rate increases the reliable range
(transmission distance). The factory-default data rate settings are suitable for the majority of applications and
should only be modified by experienced users.
Note: This rate is for Transmit messages only as radio can receive on all data rates.
The 245U-E allows for a configurable fixed rate or an Auto radio transmission rate. When a fixed rate is configured
the radio transmission rate is never altered, even under extremely poor conditions. The Auto rate will automatically
change the radio data rate to give the best throughput. When a radio transmission is unsuccessful the 245U-E will
automatically drop to the next lowest data rate and if subsequent transmissions are successful at the lower rate, the
245U-E will attempt to increase to the next highest rate. When a station connects to an access point the two devices
negotiate a data rate based which is within configured range of radio data rates for both devices.
Select the ―Radio‖ Menu to change the following configuration parameters. If a change is made, you need to select
―Save Changes‖ to retain the changes. Changes will not take effect until the unit is reset.
Radio Mode
245U-E -G support 802.11b and 802.11g radio standards and to limit operation to one or the
other, select the desired standard. Normally selecting ―auto‖ allows the modem to make the
best choice.
245U-E -A only supports 802.11a radio standard.
Transmit Power Level
This allows adjustment of the radio power. Do not set the radio power above the allowed
setting for your country You can reduce the power for short range applications, or to allow
the use of high gain transmitter antennas while still complying with the emission
requirements of your country.
See ―802.11a & TX Power‖ for dBm to mW conversion
Channel (AP Only)
245U-E-G Radio Channels 1 to 13 (depending on country) may be configured at the Access
Point. Refer Section 3.1.
245U-E -A Radio channels can be individually set (AP only – Client ignores the selection)
or left in Auto (default) and then select the appropriate U-NII groups 1,2,3,4 each one having
its own group of channels, Maximum Power and DFS selection.
The default radio channel for both A & G models is Auto, meaning on startup it will scan all
available and selected channel groups (Country dependent) and pick the quietest channel.
Channel Width (STA and
Auto Channel Only)
245U-E-G Stations only. When configured as a Station the module will periodically scan the
channels looking for an Access Point. This option is used to speed up the Access Point
scanning process of the Client radio by only scanning certain channel bands (5M, 10M, and
245U-E Wireless Ethernet User Manual
Page 38 Dec 2011
20M) or automatically scan all channels. Default is auto.
Turbo Mode
(Only for fixed Channels –
No Auto)
Selecting Turbo Mode doubles the transmit data rate offered on a Single channel. Maximum
data rate up to 108Mbps.
Only usable with other Elpro 245U-E-A&G modules configured with the same Turbo
Channel. If using the Turbo Mode feature all modem in the system will need to be
configured with Turbo mode and the correct channel to communicate.
Transmit Data Rate
The radio baud rate in Mega (million) bits per second (Mbps) for point to point radio
transmissions. The default value is Auto. Select a fixed rate to force the radio to use the
selected rate. Fixing the Tx Rate is recommended except for advanced users.
Note: Increasing the Transmit Data rate will decrease the Transmit power level. E.g.
selecting 54 Mbps fixed data rate will reduce the transmit power from 400mW down to
125mW. This is to comply with 802.11 regulations.
Beacon Interval (AP only)
This interval is the period between beacon transmissions sent by an Access Point. The
default value is 100 milliseconds, and it may be adjusted from 50 to 4095 milliseconds.
Max Distance
Configure the maximum distance the radio signal is expected to travel. This allows the
modem to compensate for the flight time of messages as they pass from the transmitter to the
receiver, and as the acknowledgement messages are returned. Setting this value larger will
cause a small reduction in throughput. Setting this value too small will cause
communications problems over longer distances. Default distance is 5km
Disable SSID broadcast.
(AP only)
This should be used to prevent unwanted eavesdroppers from detecting the radio network
System Address (SSID) by passively listening to beacon transmissions from the Access
Point. When disabled, Access Points will not transmit the System Address openly in Beacon
messages. This is particularly useful in unencrypted radio networks.
3 Address Mode
Allows compatibility with Layer 3 Bridge devices. See section 3.6 ―Compatibility‖
Save Changes
Save changes to non-volatile memory. Changes will not take effect until module is reset.
Save Changes and Reset
Save changes to non-volatile memory and reset module
Channel Selection
245U-E-G modem (2.4 GHz 802.11b/g) selection is done by picking one of the channels from the drop down
―Channel‖ list. Normal 20MHz, 5 MHz, 10 MHz or Turbo channels are available depending on country or you can
leave it in Auto and let the modem select the best channel.
245U-E-A modem (5GHz 802.11a) channel selection is shown below.
You can select an individual channel from the list keeping in mind that the channel will have some transmit and/or
DFS constraints as indicated in Section 3.1 ― Selecting a Channel‖ and ―Appendix C‖.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 39 39
If using the Auto mode you will need to select the appropriate groups that you wish to use and the modem will
automatically select an available channel from within the selected groups.
Note some of the Groups use DFS (Dynamic Frequency Selections) and if using these DFS channels
you need to be aware that there will be a minimum 60 seconds scan/monitor time that the radio
must perform to check there are no Military or Commercial Radars using the same frequency. If a
Radar is detected the radio must select another random channel and again go through the 60
second scan/monitor time.
3.10 Advanced Radio Configuration
Some of the more advanced radio settings have been moved from the normal Radio configuration page so as to
simplify the configuration process.
Care should be taken when making changes to parameters on this page.
TX Antenna
Select which antenna port the module will transmit from. Selections available are
Main Port Only – Messages are transmitted from the main ―TX/RX‖ port, The Auxiliary
port ―RX‖ is disabled.
Both (Diversity) – Both ports will be used to transmit however not at the same time; it
calculates the best port based on previous transmissions and MAC addressing. Note:
Broadcast / UDP transmission messages will initially toggle between the antenna ports, and
could result in every second message not being heard until the module learns which device
can be reached through which antenna port.
Aux Port Only – Messages will be transmitted via the Auxiliary ―RX‖ port only
RX Antenna
Same as for TX Antenna above but for the Receiver port. Setting to ―Both (Diversity)‖ will
allow a high gain antenna to be connected to the Auxiliary ―RX‖ port which will give better
RX signal gain but not increase the TX gain and possibly pushing it over the regulatory
EIRP threshold.
DTIM Period (AP only)
DTIM sets which beacon frames incorporate extra information for low power sleeping client
devices. Normally set this to 1.
RTS Threshold
“Ready To Send”
RTS frames can be used to help avoid radio collisions between two stations that cannot
directly hear each other. Any frame larger than RTS Threshold bytes will be preceded by an
RTS message. The default value of RTS Threshold is 2346, which effectively disables RTS
signaling, as this value is larger than the maximum frame size (Fragmentation Threshold).
Fragmentation Threshold
(Client Stations only). The maximum transmission unit (MTU) of data over the radio. If
more than this number of bytes is input into the module, it will be transmitted in more than
245U-E Wireless Ethernet User Manual
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one message (or fragmented).
Interference Mitigation
(AP only)
Interference Mitigation should only be turn on (Default is Off) if using Demo Whip
antenna’s or if there is a high level of background interference.
By enabling this option the radio will dynamically adjust radio parameters to help mitigate
interference based on any background interference. It will reduce the receiver sensitivity and
so should only be enabled on paths with a high fade Margin and good signal quality, etc.
Bursting
Selecting this option can increase the data throughput by reducing the overheads associated
with wireless transmissions. If communicating with a device that does not support bursting
the modem will drop back to non-bursting mode.
Enable Iperf Server
Enable Iperf Server function in the modem. Iperf is used for performing Radio surveys or
radio path testing. See section 4.4 ―Throughput Test‖
Fixed Noise Floor
Allows the Radio Receiver Noise Floor (and therefore sensitivity) to be moved above any
interference. What this will do is essentially stop the radio communicating with devices with
lower signal strength. For use in areas where there is a greater amount of interference
Fixed Noise Floor
Due to the popularity of the 2.4 GHz band, there are many sources of interference. This interference can sometimes
be a problem due to the way 802.11 devices communicate. Standard 802.11 communications uses a system called
―Clear Channel Assessment‖ which means the radio will listen before transmission and if the channel is busy it will
hold off regardless of the level of signal.
If the background interference is high due to other radio systems or noise you can raise the Fixed Noise floor to
compensate. The Channel Utilisation page can be used to identify excess noise / interference.
Raising the Noise Floor will block out any receive signal levels below the value configured under ―Fixed Noise
Floor ―on the Advanced Radio Configuration page. The value must be entered as a negative dBm number and
should be at least 8dB greater than the weakest RSSI of any connected modems, otherwise communications may be
lost.
E.g if the interfering noise levels are around -80 dB you can raise the Noise floor to -70dB to block out any signals
below making sure the RSSI levels of any connected modules are not below this Noise Floor as they will not
communicate.
The Connectivity page can be used to determine what other systems are around and what their RSSI levels are.
After configuring the fixed noise floor, confirm that the Channel Utilisation has dropped to a desirable level, and
where possible perform an iperf Throughput Test to confirm acceptable performance.
3.11 Serial Port Configuration
The 245U-E has an RS-232, and an RS-485 port for serial communications. These ports may be used for different
purposes. The 245U-E offers three different serial functions, which are PPP server; Serial Gateway; and Modbus
TCP to RTU Gateway.
RS-232 PPP Server
The 245U-E can be used as a PPP (Point-to-Point Protocol) Server to connect the wireless system to serial devices
via the RS232 or RS485 serial ports.
PPP Server enables a network connection to the 245U-E over a serial cable. This is much like dial up internet. The
maximum serial data rate is 115,200bps. Hardware or Software flow control may be selected.
With minimal configuration on the PC, you may use Dial up networking in Windows XP to connect to the network
via the serial port.
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For the 245U-E, users must configure the local IP address for the 245U-E and the remote device IP address. Some
care must be taken in selecting these IP addresses.
If you wish to use routing over this serial network connection, then the IP addresses selected must not lie
on Wireless or Wired Ethernet networks already configured into the device. You must ensure they set
routing rules appropriately for devices either side of the network.
If you want the serial device visible as present on the Wireless or Wired network, then the local IP address
must be the same as the IP address set for the desired port. A process called ―Proxy ARP‖ is used to make
the device visible on the network. In this process, the 245U-E pretends that it holds the IP address on the
network, and responds on behalf of the remote device.
The result of this is similar to bridging for a single device, with some exceptions. One of these exceptions is the
inability to handle name server searches of the network via this serial link. For example, you would encounter
difficulty if you were to use Windows Explorer over the serial link to find a PC on the wired network. For this to
operate correctly you must explicitly map computer names to IP addresses in the ―LMHOSTS‖ file on your PC.
To configure Windows XP to establish a PPP connection to a 245U-E in SETUP mode, follow these steps:
1. On Network Connections in Windows XP, select Create a new connection
2. On the New Connection Wizard, click Next
3. Set up an advanced connection
4. Connect directly to another computer
5. Set PC as guest
6. Set Connection Name
7. Select a COM port
8. Select availability
9. Click Finish
10. Select properties of this new connection by right clicking on connection.
11. General Tab click on Configure button
12. Ensure maximum speed is 115200bps, click OK
13. Select Networking Tab - click on Internet Protocol (TCP/IP) in list box and then click Properties button.
14. On Properties form click Advanced button
15. On Advanced TCP/IP Settings form- General Tab, uncheck field in PPP link stating ―Use IP header
compression‖.
16. Configuration is now complete. Click on this newly created link to establish a connection to 245U-E.
17. Ensure both the username and the password are entered exactly as configured in 245U-E. (When booted in
SETUP mode, the PPP server has username ―user‖ and password ―user‖.)
Serial Gateway (Server/Client/Multicast)
Serial Gateway functionality is available for both RS-232 and RS-485 ports independently, and enables serial data
to be routed via the wired or wireless network connection. Serial Gateway functionality is similar to radio modem
functionality, allowing point-to-point and multipoint serial data transfer.
The Serial Gateway can be configured as either as Server, Client, Multicast Group, or Modbus.
When configured as ―Server‖, the module will wait for a TCP connection to be initiated by a remote client.
When configured as ―Client‖, the module will automatically attempt to connect to a specified remote server using
TCP. When configured as ―Multicast Group‖, the module will broadcast data to all members of the same Multicast
Group using UDP.
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With the Serial Gateway Server, Client and Multicast functions it is possible for serial data from a 245U-E to be
transferred to any other 245U-E serial ports including the corresponding port on the same 245U-E.
Serial Gateway (Modbus - Modbus RTU to TCP)
When configured as ―Modbus‖, will allow a serial Modbus Client (Master) to connect with a single Ethernet
Modbus TCP Server (Slave)
With the Modbus Function the serial data is encapsulated within a TCP/IP data frame and made available on the
Ethernet network.
Both 245U-E serial ports and the hard wired Ethernet port can be configured to communicate completely separate
data streams which can all be communicating at the same time.
Some of the possible Serial Gateway topologies are illustrated below.
Access
Point
RS232
Server
Client
RS232
Device
RS485
Device
RS485
Client
Server/Client
Access
Point
RS232
Server
Client
RS232
Device
RS232
Device
RS232
Client
Server/Client
RS485
Device
RS232
Device
Client
Access Point
RS485
Multicast
Group
RS232
Multicast
Group
RS485
Multicast
Group
RS485
Device
Client
Multicast
Modbus TCP
Server (Slave)
LAN
Serial Modbus
Client
Modbus RTU
to TCP Serial
Gateway
Access PointClient
Modbus
Serial Gateway
There are software packages available (i.e. SerialIP Redirector by Tactical Software) that can create a virtual serial
port on a PC. This virtual serial port can be configured to connect to a 245U-E serial port. Standard programs can
then be used to access this serial port as if it were actually connected to the PC. Alternatively HyperTerminal may
be used to connect to a serial port on the 245U-E. When creating the HyperTerminal connection, select ―Connect
Using: TCP IP (Winsock)‖, enter the IP address of the 245U-E, and the port selected in the ―Network port‖ field.
Modbus TCP to RTU Gateway
The Modbus TCP to RTU Gateway allows an
Ethernet Modbus/TCP Client (Master) to
communicate with a serial Modbus RTU Slave.
The 245U-E makes this possible by internally
performing the necessary protocol conversion.
The conversion is always performed by the
245U-E which is directly connected to the
Modbus TCP
Client (Master)
LAN
RS232
Modbus RTU
Slave
RS232
Modbus TCP
to RTU
Gateway
Access PointClient
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Modbus serial device (i.e. only this module needs to have Modbus TCP to RTU Gateway enabled).
The above example demonstrates how a Modbus/TCP Client (Master) can connect to one or more Modbus RTU
(i.e serial) Slaves. In this example the 245U-E Access Point is configured with the ―RS232 Modbus/TCP to RTU
Gateway‖ enabled. Once enabled, the gateway converts the Modbus/TCP queries received from the Master into
Modbus RTU queries and forwards these over the RS232 port to the Slave. When the serial response to the query
arrives from the Slave, it is converted to a Modbus/TCP response and forwarded via the network to the
Modbus/TCP Master. If no response was received serially by the 245U-E within the configured Response Timeout,
the 245U-E will initiate a number of retries specified by the configured Maximum Request Retries.
The Modbus TCP to RTU Gateway may be configured to operate on either the RS-232 or RS-485 port.
3.12 Serial Menu
RS-232 / RS485 Serial Port Configuration (Common to all)
RS232 Port
Select the desired functionality. Select either PPP, Serial Gateway or Modbus TCP to RTU
Data Rate
The serial data rate desired. Serial data rates available range from 110bps to a maximum of
115,200bps.
Data Format
The data format desired. All the standard data formats are supported.
Flow Control
Selects CTS/RTS or None
RS232 PPP Server (Only RS232)
Username
User name to enter to access RS-232 PPP Server.
Password
Password to access RS-232 PPP Server.
Local IP
Address
Select the IP address of the PPP server. The remote device may be made visible on the
Ethernet or Wireless networks by either utilising proxy-arp or routing. The proxy-arp
feature may be enabled by setting the Local IP address the same as the Ethernet IP Address
or the Wireless IP Address. The module will respond on behalf of the remote device,
making it seem like the device is present on the configured network. Alternatively, if the IP
address selected is not the same as the Ethernet or Wireless IP address, routing is used to
pass data to the Ethernet and Wireless ports.
Remote Device
IP Address
Select the IP address of the remote device. Ensure this address is not the same as any other
device on the Ethernet or Wireless networks.
RS-232 / RS485 Serial Gateway Mode
Serial Gateway
Mode
Server - Module will wait for a connection to be initiated by a remote Client.
Character
Timeout
Enter the maximum delay (in msec) between received serial characters before packet is sent
via network.
Packet Size
The number of received bytes that will be buffered before a packet is sent via the network.
Listen Port
(Server)
Server Only. Enter the TCP port number on which the server must listen for incoming
connections. The standard TELNET port is 23.
Serial Gateway
Mode
Client - Module will automatically attempt to connect to the specified remote server.
Character
Timeout
Enter the maximum delay (in msec) between received serial characters before packet is sent
via network.
Packet Size
The number of received bytes that will be buffered before a packet is sent via the network.
245U-E Wireless Ethernet User Manual
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Remote Device
Port (Client)
Client only. Enter the TCP port number of the remote server (i.e. the remote port to
automatically connect to).
Remote Device
IP Address
Client only. Enter the IP Address of the remote server.
Serial Gateway
Mode
Multicast - Allows point to multi-point serial transfer. All members of the group will
receive serial transmissions made by any other member of the Multicast group.
Character
Timeout
Enter the maximum delay (in msec) between received serial characters before packet is sent
via network.
Packet Size
The number of received bytes that will be buffered before a packet is sent via the network.
Multicast
Group Port
Enter the UDP port number that all members of the group will use (i.e. all group members
should use the same port number).
Multicast
Group IP
Address
Enter a valid Multicast IP Address identifying the group (i.e. all group members should use
the same Multicast Group IP Address). Valid Multicast IP Addresses are in the range
224.0.1.0 to 238.255.255.255.
Serial Gateway
Mode
Modbus - Allows a serial Modbus Client (Master) to connect with a single Ethernet
Modbus TCP Server (Slave)
Character
Timeout
Enter the maximum delay (in msec) between received serial characters before packet is sent
via network.
Packet Size
The number of received bytes that will be buffered before a packet is sent via the network.
Modbus Server
Port
Enter the TCP port number of the remote server (i.e. the remote port to automatically
connect to).
Modbus Server
IP Address
Enter the IP Address of the remote server (i.e. the remote IP Address to automatically
connect to).
RS-232 / RS485 Modbus TCP/RTU Converter
Modbus Server
TCP Port
Port number used for the Modbus TCP – Standard port is 502.
Pauses Between
Requests
Enter the delay between serial request retries in milliseconds
Response
Timeout
Enter the serial response timeout in milliseconds – a serial retry will be sent if a response is
not received within this timeout.
Connection
Timeout
Enter the TCP connection timeout in seconds – if no Modbus/TCP data is received within
this timeout then the TCP connection will be dropped. Set this field to zero for no timeout.
Maximum
Request Retries
Enter the maximum number of request retries performed serially.
Maximum
Connections
Enter the maximum number of simultaneous TCP connections to the server allowed.
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3.13 Multicast Pipe Manager
Previously it has been difficult to connect a single TCP device, i.e. a Scada / DCS system to multiple remote
multicast serial devices.
Multicast Pipe allows this type of connection.
An example would be a Scada system that needs to communicate with multiple remote serial devices. A modem
can be placed at each remote location and connected serially to each device. A multicast pipe is configured to
communicate with all devices using a multicast address and port, i.e. 224.0.1.1:5000.
The Scada then communicates with the remotes using TCP via the IP address of the Multicast Manager and the
port selected in the configuration, i.e. 5001.
.
Multicast Pipe Manager
Enabled
Enables or disables the Multicast Pipe manager.
Server Port
Server port used by the Multicast Pipe Manager. Will need to be configured the
same as the Port on the Client, i.e. Scada, DCS, etc
Multicast Group IP Address
Broadcast Address used when communicating to all other Multicast devices. This
address will need to be the same on all communicating Multicast devices.
Multicast Group Port
Multicast Port used when communicating to all other Multicast devices. Will need
to be the same on all communicating Multicast devices.
Access
Point
LAN
Client
Multicast
Group
Multicast Pipe Enabled
Multicast Address
224.0.1.1
Port 5000
Multicast Address
224.0.1.1: Port 5000
Serial
Serial
Client
Client
Serial
Server
Client
Client
Client
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3.14 Digital Input/Output
The functionality of the shared Digital Input/Output pin may be configured via the ―I/O Transfer‖ webpage. As this
pin is shared, the Digital Input status will be ON when the Digital Output is set ON.
The Digital I/O channel can be transferred to/from another device using Modbus (see ―Modbus I/O Transfer‖
below) or it can be configured to provide status of the module communications. If the 245U-E disassociates from
another unit (that is, there is no wireless link), you can configure the digital output to turn ON (set) or OFF (drop).
3.15 Modbus I/O Transfer
The 245U-E provides Modbus TCP Client and Modbus TCP Server functionality for I/O transfer. 5000 x 16bit
general purpose registers are provided for Modbus (including the onboard Digital input/output) and are shared for
both Client and Server. Modbus TCP Client (Master) and Modbus TCP Server (Slave) are both supported
simultaneously, and when combined with the built in Modbus TCP to RTU Gateway the 245U-E can transfer I/O
to/from almost any combination of Modbus TCP or RTU devices.
The layout of the 245U-E I/O Registers is summarized in the table below. Each register is internally saved as a 16
bit unsigned integer value. A Modbus transaction may access the entire 16 bit value of any register, or alternatively
the most significant bit of a register may be accessed as a discrete value. The main use for the general purpose I/O
registers is for intermediate storage, i.e. when transferring I/O from one Modbus Slave device to another. Also
provided is the status of the onboard digital I/O, as well as the status of the wireless link. The 16 bit status register
contains the value FFFF (hex) for ON and 0000(hex) for OFF. Inverted status registers are also provided where the
registers contain 0000(hex) for ON and FFFF (hex) for OFF.
Registers
Purpose
1 – 4299
General purpose I/O registers (read/write)
4300
On-board Digital Input value (read only)
4301
Link Status (read only)
4320
On-board Digital Output value (read/write)
4370
On-board Digital Input inverted value (read only)
4371
Link Status inverted (read only)
4372-4999
Reserved for future use
Modbus TCP Client (Master) enables the 245U-E to connect to one or more Modbus TCP Servers (Slaves).
All Modbus Master messages are directed to/from the onboard I/O registers depending on configuration (described
below).
The Modbus TCP Client may also poll Modbus RTU (i.e. serial) devices connected to either the local serial port or
a remote 245U-E serial port by enabling the Modbus TCP to RTU gateway at the corresponding serial port (see
section 3.11‖Serial Port Configuration‖.
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Modbus TCP Client functionality allows a maximum of 100 mappings to be configured and a maximum of 25
different Modbus TCP Servers.
Modbus TCP Server (Slave) enables the 245U-E to accept connections from
one or more Modbus TCP Clients (Masters).
All Modbus transactions routed to the onboard Modbus TCP Server are
directed to/from the onboard general purpose I/O registers. The Modbus TCP
Server is shared with the Modbus TCP to RTU Gateway, so that the Modbus
―Device ID‖ is used to determine if a Modbus transaction is to be routed to the
onboard Modbus TCP Server or to a Modbus RTU device connected to the
serial port. Care should therefore be taken that all serially connected Modbus
devices use a different Modbus Device ID (i.e. Modbus Slave Address) to the
onboard Modbus TCP Server. Up to 32 separate connections to the Modbus
TCP Server are supported.
Modbus RTU (serial) Master functionality is achieved by combining the Modbus TCP Client (Master) and Modbus
TCP to RTU Gateway. Simply specify a Modbus TCP Client (Master) connection to a Modbus TCP Server where
the server is the address of any 245U-E with Modbus TCP to RTU Gateway enabled. Care should be taken to
ensure that the Device ID (i.e. Modbus Address) of the serial device is different to the Device ID of the onboard
Modbus TCP Server of the 245U-E that the serial device is connected to.
The 245U-E provides a configurable option to automatically reset the value of the onboard I/O registers to zero in
the event of a communications failure. If a valid Modbus transaction directed to/from a given register has not been
completed for longer than a configurable timeout, then the value of that register will be reset to zero.
An example of the Modbus functionality of the 245U-E is illustrated below. In this example the status of the
onboard digital input at C will be reflected at the onboard digital output at B. Also, 8 single bit registers from
Modbus serial device D will be transferred to A.
Unit B is configured with Modbus TCP Server enabled and Device ID = 1, Unit C is configured as shown above.
The first will write the register 4300 (Local Digital Input) to server IP address 192.168.0.200 (Unit B),
Device ID #1, register 4320 (Local Digital output).
The second mapping shows a Modbus read command of 8 Discretes starting at register 1 (Destination
Reg) on Device ID #6 connected to IP address 192.168.0.123 (it self) and store the values at register #1
locally.
Modbus RTU
Slave
Device
ID #5
Modbus TCP
Server
192.168.0.200
192.168.0.123
A
B C
D
Device
ID #1
Device
ID #6
Modbus RTU
Slave
Modbus TCP
Client
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The third mapping shows the Modbus write command (Write Coils) which is writing the local 8 I/O’s
starting at register 1 across to Server IP address 192.168.0.200, Device ID #5, destination reg #1.
The configuration of unit B is shown below (accessible via the ―I/O Transfer‖ configuration page). It can be seen
that Modbus TCP Client has been enabled with a 500msec scan rate, meaning that there will be a 500msec delay
between each of the mappings directed at any server. The ―Reset Registers on Comms Fail‖ option is enabled with
a timeout of 60 seconds, indicating that any of the registers at unit B will be reset if a successful Modbus
transaction involving that register has not been executed in the last 60 seconds. The Modbus TCP to RTU Gateway
at B must also be enabled (see section ―3.13.3 Modbus TCP to RTU Gateway‖) to allow Modbus communications
with the serial device A.
Three ―Modbus TCP Client Mappings‖ are also configured at B in order to perform the required I/O transfer. The
first mapping transfers the status of the onboard digital input at C to the onboard digital output at B. Local Register
4320 specifies the register for the onboard digital output at B (since B is the local unit at which the mapping is
configured). I/O Count 1 specifies that only one I/O point is being transferred (i.e. the single digital I/O). Function
Code 02: Read Discrete specifies the standard Modbus function code to read discrete (i.e. digital) inputs.
Destination Register 4300 specifies the register for the onboard digital input at unit C (since C is the destination
unit for this mapping). Device ID 1is the ID of the onboard Modbus TCP Server at C. Server IP Address
192.168.0.200 is the IP address of unit C – which is the Modbus TCP Server we are reading from. Response
Timeout 1000 ms specifies that unit C must respond to this message within 1000ms. Comm Fail Register 0
specifies the local register where the communications status for this mapping will be stored.
The second mapping reads 8 registers from serial unit D into onboard registers in unit B. Note that in this case the
specified Device ID 6 is the Modbus Address of the serial device D, while the Server IP Address 192.168.0.200 is
the IP Address of unit C since the Modbus TCP to RTU Gateway at unit C converts the Modbus TCP message to
Modbus RTU and routes it out the serial port to unit D.
The third mapping takes the 8 registers read by the second mapping and writes them to the serial unit A. The
specified Device ID 5 is the Modbus Address of the serial device A, and the Server IP Address 192.168.0.196 is the
IP Address of the local unit B since the local Modbus TCP to RTU Gateway is to route the message out the serial
port to unit A.
Since the 245U-E supports Modbus TCP Client and Server simultaneously, the Modbus TCP Server for unit B
above could also be enabled. This would allow one (or more) external Modbus TCP Clients anywhere on the
extended wired or wireless network to connect to unit B and monitor the status of the I/O registers – including the
I/O at units A, C, and D. This is a very powerful and flexible feature which could, for example, be exploited by a
central monitoring facility or SCADA.
Modbus TCP Configuration on I/O Transfer Menu:
Enable Modbus TCP
Server (Slave)
Check this box to enable the onboard Modbus TCP Server. All Modbus TCP connections to
the module IP Address and specified Modbus Server Device ID will be routed to the onboard
I/O registers.
Modbus Server Device
ID
Specify the Modbus Device ID for the onboard Modbus TCP Server. Allowed values are 0 to
255.
Enable Modbus TCP
Client (Master)
Check this box to enable the onboard Modbus TCP Client. I/O to be transferred via the
Modbus TCP client is specified with Modbus TCP Client Mappings.
Modbus Client Scan
Rate
Enter the delay (in milliseconds) between execution of consecutive Modbus TCP Client
Mappings to the same Server.
Reset Registers on
Comm‟s Fail
When Enabled the value in any onboard I/O register will be reset to zero if a valid Modbus
transaction directed to/from the given register has not been completed for longer than the
Comms Fail Timeout.
Comms Fail Timeout
The period of time after which onboard I/O registers will be reset if a valid Modbus
transaction directed at that register has not completed.
Enable Modbus
Statistics
Enables the Modbus Diagnostic registers as shown in Section 4.9 ―Internal Diagnostics
Modbus Registers‖ Disabling this option will free up the registers and also slightly increase
processing resources.
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Log background Noise
RSSI & BGND on Rx messages are made available in the diagnostic registers (Section 4.9
―Internal Diagnostics Modbus Registers‖ for details. For a Hex value of 5F5D the 5D byte =
RSSI and the 5F byte = BGND (Convert value from hex to dec and add a ―-―e.g. 5F = -95dB).
Enabling this option removes the Background Noise byte from these registers and so only the
RSSI value is made available.
Modbus TCP Client Mappings on I/O Transfer Menu:
Local Register
Enter the starting onboard I/O register number that the specified Modbus Master transaction
will transfer I/O to/from.
I/O Count
Specify the number of consecutive I/O register to be transferred for the specified transaction.
Function Code
Specify the Modbus Function Code for the transaction.
Destination Register
Enter the starting I/O register number in the destination device that the specified Modbus
Master transaction will transfer I/O to/from.
Device ID
Enter the Modbus Device ID of the destination Modbus device
Server IP Address
Specify the IP Address of the destination Modbus TCP Server for the specified transaction.
Response Timeout
Enter the timeout (in milliseconds) to wait for a response to the specified transaction.
Comm Fail Register
Enter the onboard I/O Register number to store the communication status of the specified
transaction. The Specified register will be set to 0 if communications is successful, 0xFFFF if
there is no connection to the specified server, or 0xFFxx where xx is the Modbus Exception
Code
3.16 Roaming
In certain cases a Client may be in a mobile situation and require a method of roaming to another Access Point.
Normal network communications provides only basic roaming behavior which means as the client moves further
from the AP it will go through a period of poor communication followed by a complete disconnection of the radio
link.
It is at this point that the Client will scan for Access Points and if one is in range it could take up to 10 seconds for
the client to establish a connection.
Fast Roaming will significantly reduce the time taken for a client to roam from Access Point to Access Point. Also
the discovery of AP’s is done before the existing radio link deteriorates therefore eliminating the periods of poor
performance during transition to the next AP.
The following settings/thresholds can be configured to fine tune the fast roaming process.
245U-E Wireless Ethernet User Manual
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Fast Roaming
Fast Roaming allows a client (station) to roam to an AP with a stronger signal strength without
disrupting communications. Or roam seamlessly between multiple Access Points based on
configuration parameters such as RSSI threshold.
Passive Scanning
(STA only)
Selecting this item stops a Client device from sending ―probe request‖ messages when it is
searching for an access point to connect to. Instead, the client waits for a beacon transmission
from the access point.
Passive Scanning should be disabled when Fast Roaming is enabled.
Roam Scan
Threshold
Background Scan will be initiated when the RSSI to the currently connected AP drops below this
threshold and Fast Roaming (above) is enabled. Default is -90dBm
Roam changeover
Threshold
This is the RSSI value above the Roam Scan Threshold that is required for the Client to change
to the new Access Point. In the example shown above the Access Point RSSI would need to be
above -84dB before it would changeover.
In general, the Roam Changeover Threshold should be at least 6dB, otherwise changeovers could
occur too frequently.
Roam check
Interval
If a better AP is not found, the background scan is repeated every Roam Check Interval while the
signal strength to the currently connected AP is below the Roam Scan Threshold. Default is
30seconds
Channel Width
Selects channel width bands for background scan. If 5MHz is selected then only 5MHz channels
will be scanned during the background scan. Default is Auto, which means all channels will be
scanned.
Save Changes
Save changes to non-volatile memory. Changes will not take effect until module is reset.
Save Changes and
Reset
Save changes to non-volatile memory and reset module
When Fast Roaming is enabled the Client goes off-channel and periodically performs a background scan to identify
available AP’s. When AP’s are identified the RSSI is recorded as a potential connection. It takes 50msec to scan
each channel, with a 1 second delay between each scanned channel. So scanning 10 channels will take 10 second,
during which time latency of up to 50msec will occur and any throughput traffic is essentially paused and buffered
for retransmission when complete. It is therefore recommended the scan list is used to limit the number of channels
the client needs to scan thus reducing the overall scan time.
During the background scan a client will scan all of the channels in the Scan List to identify better AP's. If no
channels are configured it will scan all channels.
The above configuration shows that the Client will start scanning when the RSSI of its current connection to the
Access Point falls below -90dBm. When this happens it will scan the list of Access Points configured in the
Roaming Scan List (in this case channels 1, 4 & 6, as shown below) and if any of the RSSI levels are greater than 84dBm it will change to this Access Point.
Chapter Three 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 51 51
3.17 Repeaters (WDS)
The range of a wireless network can be extended by allowing Access Points to behave as repeaters and forward
traffic to other Access Points. Access Point to Access Point communications is also known as Wireless Distribution
System (WDS). The 245U-E offers very powerful WDS configuration, allowing for a mesh network with selfhealing functionality. Alternatively, fixed AP to AP links can be configured for optimized throughput.
Each 245U-E Access Point supports up to 10 separate interfaces for WDS links to other devices.
Each WDS interface can be either a bridge or router interface (refer section 1.1 ―Network Topology‖ for more
information on bridge vs router). If you need a simple repeater network, use a bridge interface.
A WDS bridge interface allows traffic to be bridged to another Access Point on the same IP network. WDS bridge
interfaces do not require additional IP Address configuration, as they are bridged with the standard wireless
interface that is used for connections to associated clients. All of the WDS interfaces on the one Access Point may
be bridged if required.
WDS bridge interfaces have the advantage that redundant paths are permitted when using the bridge Spanning Tree
Protocol (see section 3.5 ―Spanning Tree Algorithm‖), thus behaving as a self-healing mesh network. Bridged
networks are also not as configuration intensive as routed networks. Since WDS bridge interfaces generally do not
require IP address configuration (they inherit the IP address of the standard wireless interface).
A WDS router interface allows traffic to be routed to an Access Point on a different network, and therefore requires
configuration of an IP address to reflect the network address of the destination network. WDS router interfaces
cannot provide the redundancy of bridge interfaces, but can be used to reduce radio bandwidth requirements
because the router can determine the destination based on IP address, whereas the bridge must go through a
learning phase where all broadcast traffic must be retransmitted on each interface. Routed networks may also be
used in some cases to avoid the overhead introduced by the bridge Spanning Tree Protocol when network loops
exist.
Specify SSID for AP/STA modes or MAC Address for Point to point mode.
Encryption is not inherited from the main page.
Each WDS interface can also be configured with a different encryption algorithm; however each side of a single
WDS link must specify the same encryption algorithm and keys.
Station
SSID = Area1
Access Point
SSID = Area1
Access Point
SSID = Area2
Station
SSID = Area1
Virtual Client
SSID = Link1
WDS Link
Site A Site B
Station
SSID = Area2
Station
SSID = Area2
Virtual AP
Virtual Station
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Router IP and Subnet should be left blank unless that WDS interface is to be on a different subnet. Leaving these
fields blank will mean that the WDS interface will be bridged with the default wireless interface.
When adding WDS router interfaces, you may also need to add a Routing Rule on the Routing configuration page.
Spanning Tree Protocol (STP) column only applies when two or more interfaces are bridged.
A maximum of 10 WDS Connections can be configured. (A combined maximum of 5 AP and STA virtual modules
applies.)
WDS Connections are made by adding one or more ―Virtual Modules‖ to an Access Point (as illustrated in the
diagram at the start of the section). Each virtual module can be configured with one of the standard wifi operating
modes (Access Point or Station) or a non-standard Point to Point mode.
Access Point and Station virtual modules allow for the possibility of dynamically created connections
(based on SSID) and support WPA Encryption. A combined maximum of 5 AP and STA virtual modules
can be configured per unit.
Point to point mode virtual modules provide static connections (based on MAC addresses), and cannot
support WPA Encryption. Point to point virtual modules should only be used for establishing WDS
connections with third party Access Points that do not support standard WDS operation.
All Access Points must be configured on the same fixed radio channel. Auto Channel selection
must not be selected (See “Radio Configuration” page for details on configuring the channel.)
There are many different ways to setup wireless networks; often it depends on the devices you wish to connect and
the existing network topology.
The following pages show some examples of how to connect devices into different types of systems.
Example – Extending range using WDS
One of the most common uses for WDS is to extend the range of the wireless network using repeaters. The diagram
above illustrates a simple example where the four Access Points are all at fixed locations (each of the Access Points
could, of course, have one or more client/stations connected). Since the locations are fixed, we can avoid the
overhead of using the Bridge Spanning Tree protocol here by configuring fixed WDS links to ensure that each
Access Point will only connect to the next Access Point in the chain. Any number of additional intermediate
repeaters could be added to the chain in a similar way.
Site B WDS Configuration 1
Access Point
SSID = SSID_A
192.168.0.10
STP = x
Access Point
SSID = SSID_C
192.168.0.30
STP = x
Access Point
SSID = SSID_B
192.168.0.20
STP = x
Virtual Client
SSID = SSID_B
Virtual Client
SSID = SSID_C
WDS Bridge
WDS Bridge
Site B Site C
Extending range
(Repeaters)
Access Point
SSID = SSID_D
192.168.0.40
STP = x
WDS Bridge
Site D
Virtual Client
SSID = SSID_D
Site A
Virtual AP
Virtual Station
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man_245UE_V1.8.1.docx Page 53 53
The WDS configuration for unit B is shown above (this page is accessible via the Repeaters link from the
configuration web pages). Site B is acting as an Access point for Site A, and is a client to Site C, likewise Site C is
acting as an Access Point for Site B, and a Client for Site D. Since this example is a bridged network i.e. all devices
on the same IP network and each link is using a different SSID, there is no possibility of loops (i.e. multiple paths
to the same location) therefore we do not need to incur the overhead of enabling STP (bridge spanning tree
protocol).
We specify the devices at the other end of the WDS links by SSID only –MAC addresses can be used to specify
point-to-point links to third party devices which do not support meshing via SSID.
In this example each Virtual connection is using the same Encryption method (WPA-PSK (AES) with a key of
―Pass Phrase‖, however as in example #1 the Encryption method and key can be different for each virtual link or
even disabled (no encryption). Also the Spanning Tree Protocol is disabled as there is no possibility of network
loops.
Example - Roaming with WDS Access Points
Another common use for WDS is extending the range across a large wireless network but allowing roaming
connections between access points or being able to switch to the next Access Point when out of range of the
previous Access Point.
The diagram above shows a bridging network with a number of Access Points all with the same SSID, network
structure, etc (so as the Stations can freely roam between Access Points)
Each Access Point then needs a separate connection to the next Access Point, which is done using the WDS Virtual
Access Points or Stations
Site B is acting as a Virtual AP for Site A & C, which in turn are acting as Virtual Stations.
This setup can be replicated to extend the range and will allow any Roaming Stations full connectivity across a
network
Site B WDS Configuration 2
Access Point
SSID = System_SSID
STP = √
Access Point
SSID = System_SSID
STP = √
Access Point
SSID = System_SSID
STP = √
Virtual Station
SSID = SSID_A-B
Virtual AP
SSID = SSID_A-B
Virtual Station
SSID = SSID_A-B
WDS Bridge
WDS Bridge
Site A
Site B
Site C
Roaming Client
SSID = System_SSID
STP = √
Virtual AP
Virtual Station
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Example – Adding Redundancy
In the example below, 4 x Access Points (A, B, C, & D) form a mesh network using only WDS bridge interfaces.
Each of the Access Points may also have its own clients associated. Each Access Point is configured with a
different SSID, meaning the clients associated with each Access Point are fixed.
Sites A, B, C, and D can all exchange data with each other (as can all of their Stations) as if they were all on the
same wired segment. It can be seen that there are redundant paths and therefore the possibility for loops to occur, so
the bridge Spanning Tree Protocol should be enabled and depending on the size of the mesh possibly configuring a
Bridge Priority.
Bridge Priority is used to determine the connection priority when selecting an interface to put into the forwarding
state. You can assign higher priority values to interfaces that you want spanning tree to select first and lower
priority values to interfaces that you want spanning tree to select last. If all interfaces have the same priority value,
the MAC address is used to work out the priority.
To illustrate the redundancy, consider that if Site A needs to send data to Site D it has redundant paths through both
B and C. However, due to the spanning tree protocol only one of B or C will relay the data, with the other taking
over in the event of a failure.
The configuration for Site A and B are shown below. In this example, Site B uses its primary access point to act as
an access point for Virtual Stations on Site A and D, and uses a Virtual Station to act as a client to Site C. Site A
uses two Virtual Stations to act as clients to Site B and to Site C.
Site B configuration – Network Page configured as Primary Access Point
LAN
LAN
Access Point
192.168.0.2
SSID = SSID_A
STP = √, Priority = 1
Access Point
192.168.0.5
SSID = SSID_D
STP = √, Priority = 3
Access Point
192.168.0.3
SSID = SSID_B
STP = √, Priority = 2
Virtual Station
SSID = SSID_C
Virtual Station
SSID = SSID_C
WDS Bridge
WDS Bridge
WDS Bridge
WDS Bridge
WDS Bridge
Site A
Site B
Site D
Access Point
192.168.0.4
SSID = SSID_C
STP = √, Priority = 2
Site C
Redundant
Networks
Virtual Station
SSID = SSID_B
Virtual Station
SSID = SSID_C
Virtual Station
SSID = SSID_B
Virtual AP
Virtual Station
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man_245UE_V1.8.1.docx Page 55 55
Site B WDS configuration - Repeaters Page configured with Virtual Station to Site C
Site A&D WDS configuration - Repeaters Page configured with two Virtual Clients to Sites B & C.
Encryption levels and key above are shows as being different however they can be the same as in some of the
earlier examples. One reason why the Encryption level and key would be different is because the Access Point may
have clients that communicate using a different Encryption method e.g. 128 bit WEP and may not support the same
Encryption method.
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Example – WDS Routed Network
An example of using WDS router interfaces to achieve a similar physical topology to the WDS bridge example
discussed earlier is illustrated below.
In both examples, there are four WDS Access points each with the possibility of having their own client/stations
associated. In both examples A, B, C, and D can all exchange data with each other. The bridged example has the
advantage of redundancy but at the expense of extra overhead. The routed example below cannot provide the
redundancy of the bridged example, and requires more configuration effort, but does not have the overhead of using
the bridge Spanning Tree Protocol, so is suited to fixed installations that do not require redundancy.
As mentioned previously, configuration of the WDS router example is more complex than the bridged example
given earlier. Each Modem and each link have a different SSID. This is done to limit broadcast traffic and to route
data only were it needs to go.
Site B in the WDS router example above has three WDS links – to Site A, C, and D; we show Site B’s
configuration below. It can be seen that there are 3 entries in the WDS Connections list.
The first entry specifies a connection from Site B to the virtual AP at Site A whose SSID is ―SSID_AA‖,
and has a separate Router IP address of 169.254.0.3 (this is the address that Site B adopts for the link to
Site A). Note that this IP Address specifies a different network than that of the default interface for Site A
or B (i.e. default interfaces 192.168.0.X and 192.168.X respectively). It is a requirement that the virtual
interfaces at each end-point of a WDS link have the same network structure; this ensures that the WDS
links at either end point are not bridged with their default interface.
LAN
Access Point
192.168.0.2
SSID = SSID_A
Access Point
192.168.5.5
SSID = SSID_D
Access Point
192.168.5.3
SSID = SSID_B
Virtual AP
SSID = SSID_AA
169.254.0.2
Virtual Client
SSID = SSID_AA
169.254.0.3
WDS Router
169
.
254
.
0
.
X
WDS Bridge
Site A
Site B
Site D
Access Point
192.168.6.4
SSID = SSID_C
Site C
WDS Routed
Network
Virtual Client
SSID = SSID_B
192.168.0.X
SSID_A
Virtual AP
SSID = SSID_B
Virtual AP
SSID = SSID_BB
169.254.5.3
Virtual Client
SSID = SSID_BB
169.254.5.4
LAN
192.168.6.X
SSID_C
LAN
192.168.5.X
SSID_D
Virtual AP
SSID = SSID_CC
169.254.6.2
WDS Router
169.254.5.X
Virtual Client
SSID = SSID_CC
169.254.6.4
WDS Router
169
.
254
.
6
.
X
LAN
192.168.6.X
SSID_B
Virtual AP
Virtual Station
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man_245UE_V1.8.1.docx Page 57 57
The second WDS entry above specifies a WDS link from Site B to the virtual Client at Site C whose SSID
is ―SSID_BB‖ and like the WDS link to Site A uses a different Router IP address (169.254.5.X) than the
default interface. Note that this network address is also different to that used for the WDS link to Site A,
so that these separate WDS interfaces are not internally bridged. In addition to adding these WDS link to
Site A & C routing rules are required to direct traffic destined for the network address of these units, i.e.
192.168.0.X & 169.254.6.X. See below for examples routing rules.
The third WDS entry specifies the WDS link to Site D. In the example, Site D is part of the same network
structure as Site B; therefore does not require any entries in the Router IP and Subnet fields as the 245U-E
automatically bridges this interface with the default wireless interface.
A consequence of using a different network address for the WDS link between Sites B & A and Site B & C, is that
we now need to configure routing rules at Sites A, B and C so that the 245U-E’s can determine where to send
traffic destined for the other networks.
For example, if Site B receives traffic destined for network 192.168.0.x (i.e. somewhere on Site A’s network), the
routing rule specifies that the traffic must be forwarded to the end point of the WDS link to Site A. The routing
rules for Site B are shown below (for more information on routing rules, refer to the section 3.18 ―
Routing ‖).
So, in this example, Site B has a total of three IP addresses: 192.168.5.3 for the default interface; 169.254.0.3 for
the WDS link to Site A; and 169.254.5.3 for the WDS link to Site C. Note: We choose to always use the same host
address of 3 for unit B on all of its interfaces regardless of the network address.
The first routing rule specifies 192.168.0.0 as the destination address (the network address of Site A) –
because the last byte is zero, this refers to a route to the network (192.168.0.1 – 192.168.0.254 as opposed
to a route to an individual host IP). The same rule specifies the address 169.254.0.2 as the gateway address
(this is the WDS Router IP address that Site A has been configured with for its WDS link to Site B). So,
this routing rule effectively tells the 245U-E that any traffic destined for the network 192.168.0.X should
be forwarded to Site A via WDS link address 169.254.0.2.
The second routing rule will be similar except the Destinations IP address will be 192.168.6.0 with a
Netmask of 255.255.255.0, indicating all traffic for the 192.168.6.X network will be routed through the
WDS link address 169.254.5.4. This is the WDS Router IP address that Site C has been configured with
for its WDS link to Site B).
Units A and C would also require similar pairs of routing rules to direct traffic to the network addresses at the end
points of their respective WDS links. Refer to section 3.18 ― Routing ‖ for further information on routing rules.
The WDS Configuration page (as seen above) is accessible from the ―Repeaters‖ link on any of the configuration
web pages. The configurable WDS parameters are summarized below.
Routing Rules for Site B
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Add Entry Button
Add an entry to the WDS Connections table. This adds a virtual station to the device.
Delete Entry Button
Delete the currently selected entry in the WDS Connections table. To select a row, click anywhere
in the row with the mouse, to highlight the entire row.
WDS Connections:
Connection Mode
Specify the connection mode for this link. AP (Downlink) configures the connection as a virtual
access point. Sta (Uplink) configures the connection as a virtual client. Point-to-point configures the
connection as a fixed link.
SSID / MAC Address
AP Mode: Specify the SSID that this virtual access point will use. Stations connecting to this virtual
access point use this SSID.
Sta Mode: Specify the SSID that this virtual station will use when connecting to other access points.
Point-to-Point Mode: Specify the MAC address of an Access Point to establish a Fixed link with.
Usually only required for third-party devices.
Encryption
Select the required Encryption (if any) for this WDS link.
Encryption Key
Enter the Encryption key (for WEP encryption) or the passphrase (for WPA encryption). For WEP
encryption, the encryption key is set as WEP Key 1. For Sta Mode, this must match WEP Key 1 on
the Access point this virtual client will connect to. For AP mode, clients must configure their WEP
Key 1 to the same value as this key and select the Default WEP Key to be WEP Key 1.
Router IP
Leave this field blank if this WDS interface is to be bridged with the default wireless interface.
Otherwise enter the IP address for this connection that specifies the IP network to which messages
are routed.
Router Subnet
Leave this field blank if this WDS interface is to be bridged with the default wireless interface.
Otherwise enter the subnet mask of the network to which messages are routed.
STP
Applicable to WDS bridged connections only. Select the STP option if you wish to enable the
bridge Spanning Tree Protocol on this connection.
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3.18 Routing
When a 245U-E receives an IP frame that is destined for an IP address on a different network, it checks if the
network address matches the network address of one of its own interfaces (i.e. hard-wired Ethernet, or wireless
Ethernet, or WDS) and forwards the frame appropriately. However, if the IP network address does not match the
network address of any of its interfaces, the 245U-E will forward the frame to its default gateway. In this case it is
assumed that the default gateway has a valid route to the destination.
In some cases, it is not practical to have just one default gateway (i.e. routed wireless networks with more than two
245U-E routers; and in some cases when WDS router interfaces are used). If more than one ―next-hop router‖ is
required, the 245U-E allows for up to 30 routing rules to be configured. A routing rule specifies a destination
network (or host) IP address and the corresponding next-hop router that messages for the specified destination will
be forwarded to. It is assumed that the next-hop router (or gateway) will then deliver the data to the required
destination (or forward it on to another router that will).
The above network diagram illustrates a situation where routing rules may need to be configured. In this example,
the 245U-E clients need only specify the Access Point as their default gateway (i.e. they require no routing rules be
configured). However, for the Access Point to be able to deliver traffic to LAN B and LAN C it needs to have
routing rules configured that specify the respective 245U-E client/routers as next-hop routers (i.e. gateways) to
networks B and C. Note that devices on LAN A should specify the 245U-E Access Point as their default gateway.
An alternative to adding routing rules to the 245U-E in this example would be for each device on LAN A that needs
to communicate with LANs B and C to have independent routing rules specifying the 245U-E clients at B and C as
gateways to those networks.
The routing rules for the Access Point in the above example are shown below. The first entry shows the route to
LAN B. The gateway for the route to LAN B is configured as the wireless IP address of the 245U-E client
connected to LAN B. The destination for the route is configured as the network address of LAN B. Because the
host id of the destination IP address is 0, it specifies a network address. Consequently, any traffic received at the
Access Point with destination IP address 169.254.109.x (where x is any host id) will be forwarded to the 245U-E at
LAN B.
Devices on LAN B & LAN C that needs to send messages back to LAN A will need to have their Gateway
addresses directed to the 245U-E on their respected networks. I.e. a LAN B device needs to send data back to LAN
A. The Gateway address will need to be configured as 169.254.109.40 as this is the IP address of the wired side of
the LAN B 245U-E. Any message coming in with a 192.168.0.X IP address will be directed across the wireless
interface to LAN A.
LAN C
Client
Router
Access Point
Bridge
LAN A
Client
Router
Client
Bridge
LAN B
192.168.0.34
192.168.109.40
192.168.102.17
192.168.0.72
192.168.0.34
192.168.0.72
192.168.0.73
192.168.0.74
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The Routing Rules configuration page can be accessed by selecting the ―Routing‖ link on any of the configuration
web pages. Up to 30 routing rules may be added to each 245U-E. The table below summarizes the configurable
parameters of a routing rule.
Note: Entering dedicated Ethernet Routes can also be added to the wired Ethernet LAN in place of
generating / adding routing rules into the modems.
Name
A name to describe the routing rule (Max 32 characters).
Destination
The destination network (or host) IP address (to specify a network address set the host address to 0.
i.e. for an IP address 192.168.0.0 with Netmask 255.255.255.0 would specify a destination network,
while 192.168.0.16 specifies a destination host).
Subnet Mask
The subnet mask for the destination network.
Gateway
The IP address of the next-hop router for the specified destination.
Enabled
Check this box to enable the rule. You can Uncheck the box to disable a routing rule without
needing to re-enter the information at a later time.
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3.19 Filtering
When configured as a Bridge, the 245U-E will transmit all broadcast messages appearing at its wired Ethernet port.
When the 245U-E is configured as a Router, this does not occur.
In many cases, the intended recipient of the broadcast traffic does not lie at the opposite end of a proposed radio
link. Reducing unnecessary broadcast traffic sent over the radio link, will increase available bandwidth for data.
The 245U-E has a filtering feature to help reduce unnecessary wireless transmissions and enhance security.
The 245U-E may be configured to reject or accept messages to and from certain Addresses. To accept wireless
messages from particular devices a ―Whitelist‖ of Addresses must be made. Alternatively to reject messages from
particular devices, a ―Blacklist‖ of Addresses must be made. Filtering applies only to messages appearing at the
wired Ethernet port of the configured 245U-E.
The Filter comprises of three lists: MAC Addresses, IP Address/Protocol/Port and ARP Filters. Each list may be set
as either a Blacklist (to block traffic for listed devices and protocols), or as a Whitelist (to allow traffic for listed
devices and protocols). The Filter operates on four rules listed below.
The MAC Address filter is always checked before the IP Address filter.
If a message matches a MAC filter entry, it will not be subsequently processed by the IP filter. If the MAC
filter list is a Whitelist, the message will be accepted. If the MAC filter list is a Blacklist, the message will
be dropped.
The MAC address list checks the Source address of the message only.
The IP Address filter checks both the source address and the destination address of the message. If either
address match, then the rule is activated.
ARP filtering applies only to ARP request packets (typically these are broadcast packets) which are
sourced from the Ethernet interface and destined for the wireless interface. (ARP requests from devices on
the wireless network will always be passed to the Ethernet interface. ARP response packets will always be
passed).
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When configuring a Whitelist it is important to add the Addresses of all devices connected to the 245U-E wired
Ethernet port, that communicate over the wireless link. It is particularly important to add the Address of the
configuration PC to the Whitelist. Failure to add this address will prevent the configuration PC from making any
further changes to configuration. Design of the filter may be simplified by monitoring network traffic and forming
a profile of traffic on the wired network. Network Analysis software, such as the freely available ―Wireshark‖
program, will list broadcast traffic sent on the network.
For example, in the example, Device B needs to
communicate with Device E via modems C & D.
The Filtering requires that at Modem C has Device
B in its Whitelist and Modem D has Device E in its
Whitelist. With this filtering Device A will be not
be able to access Device E, as Device A is not
present in the Whitelist in Modem C.
If radio links are chained together to form a radio
backbone, it is also important to consider the
operation of the Layer 3 Transparent Bridge (Refer
Section 3.8). A 245U-E Client will act as a MAC
Address translator, as it acts as a MAC address proxy on behalf of devices connected to its wired Ethernet port.
Addition of 245U-E Client MAC addresses into intermediate 245U-E units’ Whitelist filters may be required for
correct operation.
If an erroneous configuration has prevented all access to the module, SETUP mode can be used to
restore operation.
MAC Address Filter Configuration:
MAC addresses are uniquely assigned to each device and so can be used to permit or deny network access to
specific devices through the use of Blacklists and Whitelists.
In theory, MAC filtering allows a administrators to permit or deny network access to hosts associated with the
MAC address, though in practice there are methods to circumvent this form of access control through address
modification
The MAC filter entry will match only the source MAC address in the packet.
Note: It is important to add the MAC Address of the configuration PC when creating a Whitelist.
If the configuration PC is not on the Whitelist, it will be unable to communicate with the module
for further configuration.
Select “Blacklist” or
“Whitelist”.
Blacklist will prevent all listed devices from accessing the module and using the radio link.
Whitelist will allow devices with the MAC addresses listed to communicate with the
module and utilize the radio link. All other devices are blocked.
Add Entry
Add a row to the table of Mac Address filter rules
Delete Entry
Delete the currently selected MAC address filter rule.
Enable
Check to enable the rule.
Mac Address
Enter the desired source MAC Address
Save Changes
Save changes to non-volatile memory (Reset is required to activate)
Save Changes and Reset
Save to non-volatile memory And restart to activate changes
IP Address Filter Configuration:
The IP filter allows can be used to permit or deny network access to specific devices through the use of Blacklists
(blocking of traffic that matches a rule) and Whitelists (allow traffic that matches a rule).
The IP filter entry will match either source or destination address in the packet. That is, if either the source or
destination IP address falls within the address range specified in the rule, the packet is matched and will be
discarded (Blacklist) or allowed (Whitelist).
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If the protocol is specified, the protocol of the packet must also match. If the protocol is TCP or UDP the source or
destination TCP/UDP can also be inspected. If the IP address and protocol matches and the source or destination
port number falls within the range specified, the packet is matched.
Note: Configuration pages use TCP protocol on ports 80 and 443. Create Whitelist rules specifying
the configuration PC's IP address, with TCP protocol, ports 80 and 443.
ARP Filter Configuration
ARP (Address Resolution Protocol) is a broadcast message and is primarily used for finding a MAC address when
only its IP or some other Network Layer address is known.
On large networks, you generally tend to get a high proportion of broadcast messages. Using ARP filters is useful
for reducing broadcast traffic on the wireless network by only allowing ARP requests for known units to pass, or
blocking ARP requests for high use addresses.
3.20 DHCP Client Configuration
DHCP (Dynamic Host Configuration Protocol) allows DHCP Clients to automatically obtain their IP Address at
start-up. This simplifies network administration, as there is no need to manually configure each device with a
separate IP Address. The 245U-E is able to act as a DHCP client. To set the 245U-E to acquire its IP address from a
DHCP Server, check the box ―Obtain IP Address Automatically‖ on the Network Configuration page.
When configured as a DHCP Client the ―Device Name‖ on the Module Information page will be the module
identifier (as the IP address will be unknown) and so should be given a unique name.
Select “Blacklist” or
“Whitelist”.
Blacklist will prevent all listed devices from accessing the module and using the radio link.
Whitelist will allow devices with the IP addresses listed to communicate with the module
and utilize the radio link. All other devices are blocked.
Add Entry
Add a row to the table of IP Address filter rules
Delete Entry
Delete the currently selected IP address filter rule.
Enable
Check this box to enable the rule
IP Address Min,
IP Address Max
These set the range of IP addresses. All addresses within the specified range are affected by
the rule.
Port Min,
Port Max
When the protocol is set to TCP or to UDP, this is the range of port addresses to which the
rule applies. When protocol is set to All or to ICMP, these settings have no effect.
Protocol
This chooses the protocol to which the rule applies. The rule can apply to Any protocol
(All), or to only one of TCP, UDP, or ICMP (Ping).
Save Changes
Save changes to non-volatile memory (Reset is required to activate)
Save Changes and Reset
Save to non-volatile memory and restart to activate changes
Select “Blacklist” or
“Whitelist”.
A Blacklist will block ARP requests that match the entry.
A Whitelist will allow only ARP Requests that match the entry. All other devices are
blocked.
Add Entry
Add a row to the table of ARP Address filter rules
Delete Entry
Delete the currently selected ARP address filter rule.
Enable
Check this box to enable the rule
IP Address
This sets the IP address that you wish to filter.
IP Netmask
Sets the IP Netmask
Save Changes
Save changes to non-volatile memory (Reset is required to activate)
Save Changes and Reset
Save to non-volatile memory and restart to activate changes
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3.21 DHCP Server Configuration
The 245U-E is able to act as a DHCP server, supplying IP addresses automatically to other DHCP Client devices.
Note that the 245U-E units need to act in conjunction with their connected devices. If a connected device is a
DHCP server, the local and remote 245U-E units can be configured as DHCP Clients and receive IP addresses from
the server device. Similarly, if a 245U-E is configured as a DHCP server, it can provide IP addresses to DHCP
Clients, both 245U-E units as well as other connected devices. Configuration items for the DHCP Server are listed
below.
Enabled
Tick this box to enable the DHCP Server
IP Range Minimum /
Maximum
The DHCP Server will assign IP addresses to DHCP Clients from within this range of addresses.
Gateway / Primary DNS
/ Secondary DNS
These Settings are common to all of the DHCP Clients, and refer to the gateway address, and
Domain Name Service (DNS) Configuration
Lease Time
This is the number of seconds the client is granted the assigned IP address. The client should
renew its lease within this time.
3.22 DNS Server Configuration
DNS (Domain Name Service) allows devices to be given human-readable names in additions to their IP address.
This makes identification of devices (hosts) simpler, and makes it possible to identify devices which have been
automatically assigned their IP address by a DHCP server (See section 3.21 ― DHCP Server Configuration‖).
DNS is the system which translates internet names (such as www.elprotech.com) to IP Addresses. The ELPRO
245U-E can act as a DNS Server for a local network. Name to IP address mapping are automatically updated by the
built in DHCP server when it issues an IP address to a client unit.
For the DNS Server configuration to be effective, Each DNS Client must be configured with the address of this
DNS server, as either the primary or secondary DNS (secondary DNS is only used if there is no response from the
primary DNS). Normally, this is done by setting the primary DNS field of the DHCP server configuration to the
wireless IP address. This address is then provided to client units to use as their primary DNS server address when
the DHCP server issues an IP address. The DNS Server is configured using the following settings.
Enabled
Tick this box to enable the DNS Server
Domain Name
This is a common suffix applied to the name of each device in the network. If your network is part
of a larger network, this would be assigned to you by the relevant naming authority. If your
network is stand-alone, this field is set to an arbitrary name of your choice.
Device Name (Host
Name)
This is the DNS name of the local device. (Commonly referred to as the host name or computer
name). This setting is duplicated on the main Module Information configuration page. This is the
name which is used to refer to this device. (Refer Section 3.23 ―Module Information
Configuration‖)
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3.23 Module Information Configuration
Module Information Webpage Fields
This configuration page is primarily for information purposes. With the exception of the password, the information
entered here is displayed on the home configuration webpage of the 245U-E.
Username
Configuration of Username. This is the username used to access the configuration on the
245U-E. Take care to remember this username if you change it as it will be needed to access
the 245U-E in future.
Password
Configuration of Password. This is the password used to access the configuration on the
245U-E. Take care to remember this password if you change it as it will be needed to access
the module in future.
Device Name
A text field if you wish to label the particular 245U-E. This is also the DNS name
(hostname) of the device if you are using DNS.
Owner
A text field for owner name.
Contact
A text field for owner phone number, email address etc.
Description
A text field used for a description of the purpose of the unit.
Location
A text field used to describe the location of the 245U-E.
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3.24 Configuration Examples
Setting a 245U-E to Factory Default Settings
Access configuration webpage on the 245U-E. Refer
section”3.2”.
Click on ―System Tools‖ Menu Item
Click on Factory Default Configuration Reset, and wait for
unit to reset. While the module executes the reset sequence
the OK LED will flash. The OK LED will turn green when
the reset sequence is complete.
Extending a wired network
Access Point Configuration
Connect straight through Ethernet cable between PC and 245U-E.
Ensure configuration PC and 245U-E are setup to communicate on the same network
Set dipswitch to SETUP mode.
Power up unit, and wait for the OK LED to cease flashing.
Adjust PC network settings
Set Configuration PC network card with network setting of IP address 192.168.0.1, Netmask 255.255.255.0
Open configuration webpage with Internet Explorer at address https://192.168.0.1XX/ where XX is the last two
digits of the module’s serial number
When prompted for password, enter default username ―user‖ and password ―user‖
Click ―Network‖, and select Operating Mode as Access Point.
Select Device Mode as Bridge.
Change the Gateway IP Address to 192.168.0.1
Change the Ethernet and Wireless IP addresses to 192.168.0.200
Change Ethernet and Wireless Subnet masks to 255.255.255.0
Enter a System Address (ESSID) string
Select the Radio Encryption required.
Set dipswitch to RUN
Save the changes and unit will restart with new settings.
Client 1 Configuration
Perform the same configuration steps as the Access Point configuration with the following differences:
Set the Ethernet and Wireless IP addresses of 245U-E to 192.168.0.201
Set the Operating Mode to Client.
Ensure the ESSID and Radio Encryption method match the Access Point.
If encryption is used, ensure the encryption keys or passphrase match the Access Point.
Client 2 Configuration
As above, however set the Ethernet and Wireless IP addresses as 192.168.0.202
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Connecting two separate networks together
LAN A Configuration
In this example, LAN A is connected to the internet via a router at IP address 192.168.0.1.
Devices on LAN A that only require access to devices on LAN A and B, should have their gateway IP address set
to the 245U-E Access Point as 192.168.0.200.
Devices on LAN A, that must interact with devices on LAN A and B and the internet should set the internet router
192.168.0.1 as their gateway, and must have a routing rule established for devices on LAN B. On PCs, this may be
achieved with the MS-DOS command ROUTE. For this example use: ROUTE ADD 169.254.102.0 MASK
255.255.255.0 192.168.0.200
LAN B Configuration
All devices on LAN B should be configured so their gateway IP address is that of the 245U-E Access Point as
169.254.102.54
Access Point Configuration
Connect straight through Ethernet cable between PC and 245U-E.
Ensure configuration PC and 245U-E are setup to communicate on the same network
Set dipswitch to SETUP
Power up unit, and wait for LINK led to cease flashing.
Adjust PC network settings
Set Configuration PC network card with network setting of IP address 192.168.0.1, netmask 255.255.255.0
Open configuration webpage with Internet Explorer at address https://192.168.0.1XX/
When prompted for password, enter default username ―user‖ and password ―user‖
Enter ―Network‖, and select Operating Mode as Access Point.
Device Mode should be set to Router.
Set the Gateway IP address to 192.168.0.1
Set the Ethernet IP address to 192.168.0.200, network mask 255.255.255.0
Set the Wireless IP address to 169.254.102.54, network mask 255.255.255.0
Select the Radio Encryption required, and enter encryption keys or passphrase if necessary.
Set dipswitch to RUN.
Click on button Save to Flash and Reset. Webpage will display that message indicating details are being written to
flash. Wait for 245U-E to reboot before removing power. Enter a System Generator String
Client Configuration
Perform the same configuration steps as the Access Point configuration with the following differences:
Client
Bridge
Access Point
Router
192.168.102.54
192.168.0.200
255.255.255.0
LAN A
LAN B
192.168.102.53
255.255.255.0
192.168.102.53
Internet
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Enter ―Network‖, and select Operating Mode as Client.
Device Mode should be set to Bridge.
Set the Gateway IP address to 169.254.102.54
Set the Ethernet IP address to 169.254.102.53, network mask 255.255.255.0
Set the Wireless IP address to 169.254.102.53, network mask 255.255.255.0
Click on button Save to Flash and Reset. Webpage will display that message indicating details are being written to
flash. Wait for 245U-E to reboot before removing power.
Extending range of a network with a Repeater hop
Configure units as described in ―Extending a wired network‖ of ―Configuration Examples‖ above. Place the
Access Point at the remote intermediate repeater location. Additional repeaters can be added using ―Repeaters
(WDS)‖ – refer 3.17 ‖ for further above.
192.168.0.0
255.255.255.0
Access
Point
Client 2
Client 1
LAN
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Chapter 4 DIAGNOSTICS
4.0 Diagnostics Chart
LED Indicator
Condition
Meaning
OK
GREEN
Normal Operation
OK
RED Continuously
Supply voltage too low.
OR Internal Module Fault
OK
RED At Power On
Boot Loader delay at start-up
OK
Fast Flash RED / GREEN
Module Boot Sequence
OK
Slow Flash RED / GREEN
Module Boot Sequence
Radio RX
GREEN flash
Radio receiving data
Radio RX
RED flash
Radio receiving data (Low Signal strength)
TX/LINK
GREEN
Connection Established to remote device
TX/LINK
RED Flash
Radio Transmitting
RS-232
GREEN flash
Data sent from RS-232 Serial Port
RS-232
RED flash
Data received to RS-232 Serial Port
LAN
ON
Link Established on Ethernet port
LAN
Flash
Activity on Ethernet port.
RS-485
GREEN flash
Data sent from RS-485 Serial Port
RS-485
RED flash
Data received to RS-485 Serial Port
DIO
GREEN
Digital Input is grounded.
DIO
RED
Digital Output is active
DIO
Off
Digital Output OFF and Input is open circuit.
The green OK LED on the front panel indicates correct operation of the unit. This LED turns red on failure as
described above. When the OK LED turns red shutdown state is indicated. On processor failure, or on failure during
start-up diagnostics, the unit shuts down, and remains in shutdown until the fault is rectified. During Module, boot-up
the OK LED flashes RED-GREEN until the boot sequence is complete.
Boot Status LED Indication during Start-up
The OK LED indicates the status of the module during the boot up process. At power on, the OK LED comes on
RED. During kernel boot the OK LED flashes Red-Green at a 1Hz rate (½ second red, ½ second green). During
module initialisation, the OK LED flashes Red-Green at 0.5Hz rate (1-second red, 1-second green). When
initialisation is complete, the OK LED switches to green continuously.
If the OK LED remains red at power on, this could indicate either low supply voltage (The module will not attempt
to boot until supply voltage is within range); Module fault; or a long boot delay. To check if the boot delay is the
problem, plug a terminal into the RS-232 serial port and configure for 115,200 baud, 8 data, no parity.
4.1 Connectivity
The Connectivity webpage displays connections and available networks. The ―Connected Devices‖ section displays
the radio channel, received signal strength, and radio data rate for each Client or Access Point by their MAC
Address. The readings shown are based upon the last received data message from the Access Point or Client. Client
stations also display a list of detected Access points (Site Survey), including network name (SSID), channel and
maximum data rate.
Note that when updating the Connectivity webpage, it is necessary to hold down the <ctrl> key while
pressing the refresh button. Otherwise, the information will not be updated.
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Connectivity Parameters
AID
Association ID: Every Client gets a unique temporary ID from the AP
CHAN
Channel: What radio channel is being used.
RATE
Radio Data Rate:
RSSI
Radio Signal Strength Index (Amount of received signal strength).
BGND
Background interference level in dBms: The amount of internal noise the radio is able to hear. This
level does not indicate external radio interference noise level
CAPS
Capabilities (Ref 802.11 Standard)
Site Survey
Site Survey is a one off snapshot showing what Access Points are available for connection.
This list is only available on Clients and only available at start-up of the module or by selecting Background
Scanning on the radio page.
Site Survey
SSID
The Service Set Identifier or Network Name used to identify a particular network.
BSSID
BSSID is the MAC (Medium Access Control) address of the AP (Access Point)
CHAN
Channel: What radio channel is being used.
RATE
Maximum Radio Data Rate
S:N
Signal Strength and Noise Level. In the case above signal is -44dB and background is -88dB
INT
Beacon Interval
CAPS
Capabilities (Ref 802.11 Standard)
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4.2 Channel Survey (Utilisation)
Channel Utilisation gives a visual display of how busy the current channel is over a given time period. Channel
Utilisation is made up of 3 components: transmissions made by this radio; data received by this radio; and noise or
interference that this radio can hear. These 3 components may also be viewed individually on the ―Custom Survey‖
page. Channel Utilisation is logged by the radio for 3 separate time intervals: every second for the last 60 seconds;
every minute for the last 60 minutes; and every hour for the last 60 hours.
The Elpro 802.11 Ethernet modem utilizes a half duplex radio channel for communications. At any given time, an
Access Point and its associated clients occupy a radio channel. These radio channels, or frequencies, are license free
and may contain interference from any number of other radio transmitters. When installing or diagnosing a 245
modem, the potential capacity of a given radio channel will be reduced by the existence of these other RF signals on
the same channel.
Channel Utilisation allows us to see how much RF activity is on a given channel as a percentage of the total
utilisation. A channel that is very busy will have high channel Utilisation (usually 50% or greater). Conversely a
channel that is quiet will have low channel utilisation.
Channel Survey and Custom Survey can therefore be valuable tools to use when performing site surveys in order to
determine the best RF channel to use. It is also a valuable diagnostics tool for identifying the spare capacity on a
given channel, as well as possible sources of interference.
Channel Utilisation on a Live System:
Channel Utilisation can be used on a live system to get an indication of how much spare capacity the channel has for
additional data transfer. To identify possible interference on the current channel, observe the Percent Busy and
Percent Rx on the Custom Survey page. If possible, also temporarily disable all data transfer on the system, and if the
Channel Utilisation remains high this will confirm the presence of interference.
Using Channel Utilisation for Channel Selection or RF Path Testing:
When used on an inactive system, the Channel Utilisation will indicate how quiet the current channel is, and
therefore indicate how much interference is present. To select the quietest channel, configure the radio as an Access
Point with no data transfer, and on each channel of interest record the Channel Utilisation over a period of time. The
channel with the lowest Channel Utilisation will be the quietest channel, and therefore is likely to provide the best
performance. This procedure, in addition to a Throughput Test, is recommended for complete radio path testing.
Diagnosing Low Throughput:
When iperf throughput testing has given poor results, Channel Utilisation can be used to confirm whether or not the
poor results were due to interference. If the Channel Utilisation (excluding the time period while iperf was running)
is seen to be high, then this will confirm that the poor throughput was due to other RF interference. Alternatively if
the Channel Utilisation is seen to be low (indicating little interference), then the poor throughput would more likely
be attributed to poor RSSI - which could be confirmed on the Connectivity page.
Solutions for High Channel Utilisation:
When substantial interference has been identified using Channel Survey or Custom Survey, the simplest solution is to
change to another channel that is seen to have lower Channel Utilisation. If a better channel is not available,
configuring a fixed noise floor can often greatly improve performance. Configuring a fixed noise floor can be
performed on the Advanced Radio Configuration page. The fixed noise floor should be at least 8dB greater than the
weakest RSSI of any connected modem, otherwise communications could be lost. After configuring the fixed noise
floor, confirm that the Channel Utilisation has dropped to a desirable level, and where possible perform a Throughput
Test to confirm acceptable performance.
Channel Survey screen displays a graph showing the percentage of time that a channel is being utilised by any of the
following causes:
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1) The connected modem is transmitting.
2) The connected modem is receiving valid data from another modem.
3) The connected modem has detected RF noise or interference.
Channel Survey shows the Channel Utilisation and Noise Floor Graph with 1 second, 1 minute and 1 hour periods.
The first screen shows a percent of the overall radio traffic on the channel that is currently being used.
The next screen shot shows the radio receive noise floor for the last 60 seconds.
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The third screen shot shows the average Channel Utilisation for each minute up to one hour. It will also give a
running average for the total number of minutes up to 59 minutes.
The next screen shot shows the running radio receive noise floor average for each minute up to 59 minutes.
The Channel Survey page also shows two other screen shots (not shown here) which indicate the Percent Channel
Utilisation and Noise Floor in one hour intervals. The screens will only show the last 24 hour period.
4.3 Custom Survey
Custom Survey is essentially the same as the Channel Survey (explained in the previous section) except the three
channel Utilisations can be turned on or off thus showing the different amount of traffic related data.
Percent Radio TX – Any transmitted messages from the radio to other devices.
Percent Radio RX – Any DSSS or OFDM messages received by the radio (basically any Standard Wi-Fi data packets
from either ELPRO or competitor radios).
Percent Busy (CCA or Noise) – Clear Channel Assessment is the detection of any ongoing transmissions or noise,
i.e. Microwaves, 2.4Ghz FHSS, Cordless Phones, RC devices, etc.
By configuring the different chart options we can get a clear idea of the amount of data being transmitted, received
and the amount of other noise that can be heard at the radio.
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Configure what is to be logged on each chart, select a time interval and save changes and the charts will then be
displayed below the settings. Click the button again to manually redraw the graphs.
Each graph will display a Percent Channel Utilisation using the selected criteria and time interval (Seconds, Minutes
or Hours).
Example One.
Chart one shows the amount of data that is being transmitted over a Wi-Fi link and chart two shows the amount of
data being received from all sources (Wi-Fi and other noise). We can see from this that there is very little outgoing
data but you can see a constant stream of data being received.
Example Two.
In the second example we can see that chart one shows the amount of Data being received from Wi-Fi devices and
chart two shows the amount of other noise that is being received. From this you can see that in the last 60 second
period there was a 20 second interval with around 60-80 % channel Utilisation in this case from a 2.4GHz FHSS
telemetry device.
With this sort of outside interference it is recommended to perform the same test but over a longer period so as to get
a clearer indication of channel Utilisation.
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4.4 Throughput Test
The performance of a wireless link is best measured in terms of the maximum throughput that can be achieved. The
recommended method of measuring throughput is with the "Iperf" utility. Iperf has client and server functionality,
where the server waits for a client connection. For wireless links, it is recommended that Iperf throughput testing is
performed on point to point links while the remainder of the wireless network is inactive (i.e. not sending any data).
Iperf is built into the modems for convenience, and allows measurement of TCP throughput with default Iperf
parameters. The internal Iperf utility always gives a lower result than running Iperf externally because of the
additional load placed on the internal microprocessor. Even so, the throughput results still gives an excellent
indication of link performance as long as you compare the measured result against the expected result in the table.
See Appendix E ―External Iperf Test‖ for details on running this application externally.
Internal Throughput Test
Before testing ensure that the end node of the Wi-Fi Link that you wish to test has the Iperf Server enabled under the
Advanced Radio Settings page and Saved to Flash and the module has been reset. See 3.10 ―Advanced Radio
Configuration‖
Connect to the web page of the module that will be performing the Iperf test, select ―System Tools‖ link on the right
hand side of the webpage and then select ―TCP Throughput Test‖ and you will see the Screen as shown below.
Note: TCP Throughput test must be run using Microsoft Internet Explorer 8 or later
Enter the IP address of the remote device that you wish to test and press the ―Measure Throughput‖ button.
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The specified IP address must be running Iperf in Server mode (if the remote modem does not have the Iperf server
running then you will get the following Error message on the web page, ―Iperf error, check connectivity to server.‖
Ensure that it has been enabled and the module has been reset. Each press of the ―Measure Throughput‖ button will
perform a TCP throughput test of 10 second duration.
You will see the message ―Performing Iperf Test‖ text and and if you look at the modules you will see the TX/Link
& RX Led’s flashing very fast as it performs the test. Approximately 10 seconds later a graph showing the actual
throughput over the 10 second period and a calculated average will be displayed.
The graph below shows the data throughput range between 8 and 14.5Mbits per second with an overall average of
10.9Mbits per second.
It is recommended to perform this throughput test a number of times to get better sample of the overall throughput.
The expected throughput will depend on a number of things, the distance setting, selected channel width, and
whether using the internal Iperf utility or running Iperf externally on a laptop or PC (at both ends of the link).
The following table shows real world throughput estimates based on channel selection and receiver signal levels.
Throughput is calculated using the inbuilt ―Iperf‖ utility and communicating TCP/IP over the three different
bandwidth channels (20M, 10M, & 5M). These estimates are not necessarily the maximum that are achievable in the
modems but are used more as a guideline to determine the performance of the radio link.
See Appendix E for details on using the external Iperf throughput test.
The Iperf throughput result provides an excellent measure of the performance of a radio link. In general, if the results
you get are a lot worse than the best case values listed below, this is a certain indication that the radio link has either
poor RSSI, or high noise or interference, or both.
245U-E Radio Data Throughput
Distance
Iperf
20MHz
10MHz
5MHz
1000m
Internal
10.5 Mbps
7.5 Mbps
5. Mbps
1000m
External
16. Mbps
10.5 Mbps
6. Mbps
3000m
Internal
10. Mbps
7. Mbps
4.7 Mbps
3000m
External
15. Mbps
9. Mbps
6. Mbps
5000m
Internal
9. Mbps
6. Mbps
4.5 Mbps
5000m
External
13. Mbps
8. Mbps
6. Mbps
10000m
Internal
7. Mbps
5. Mbps
4. Mbps
10000m
External
10. Mbps
7. Mbps
5. Mbps
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Throughput and Repeaters
It should also be noted that if using repeaters to extend the range there will be a reduction in throughput for each
repeater hop.
The following table shows the drop in throughput for each hop and for each of the channel widths.
Rep Hops Rep Hops
1 2 3 4 1 2 3 4 1 2 3 4
Signal Signal
1000m Internal 10.5 5.3 2.6 1.3 7.5 3.8 1.9 0.9 5.0 2.5 1.3 0.6
1000m External 16 8.0 4.0 2.0 10.5 5.3 2.6 1.3 6.0 3.0 1.5 0.8
3000m Internal 10 5.0 2.5 1.3 7.0 3.5 1.8 0.9 4.7 2.4 1.2 0.6
3000m External 15 7.5 3.8 1.9 9.0 4.5 2.3 1.1 6.0 3.0 1.5 0.8
5000m Internal 9 4.5 2.3 1.1 6.0 3.0 1.5 0.8 4.5 2.3 1.1 0.6
5000m External 13 6.5 3.3 1.6 8.0 4.0 2.0 1.0 6.0 3.0 1.5 0.8
10000m Internal 7 3.5 1.8 0.9 5.0 2.5 1.3 0.6 4.0 2.0 1.0 0.5
10000m External 10 5.0 2.5 1.3 7.0 3.5 1.8 0.9 5.0 2.5 1.3 0.6
Data Throughput based on Repeater Hops
20 MHz Channel
10 MHz Channel
5MHz Channel
The 40MHz Turbo channels rarely give a better throughput than the 20MHz in real world because it occupies a larger
portion of the 2.4GHz band and is more prone to interference.
For RSSI or Received Signal Strength Indication see section 4.1 ‖Connectivity‖
For information on checking interference or noise see section 4.2 ―Channel Survey‖
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4.5 Statistics
The Statistics webpage is used for advanced debugging of 245U-E. This webpage details the state of the 245U-E and
performance information. This page is typically useful to ELPRO technical support personnel in diagnosing
problems with the module.
Note that when updating the Statistics webpage, it is necessary to hold down the <ctrl> key while
pressing the refresh button. Otherwise, the information will not be updated.
Wireless Statistics
The ―Wireless Statistics‖ is the main area for further diagnostics statistics.
The list of statistics produced is dynamic and may vary depending on the model and configuration, i.e. 2.4.GHz,
5GHz or 900MHz & Client or Access Point.
Access Point:
Beacon Miss Count: Number of Beacons unable to be sent (100msec intervals) due to Interference or CCA
Beacon Missed Reset Count: After 15 Consecutive Beacon misses (1.5seconds) will increment by 1. This will
indicate high interference as AP is holding off sending Beacon and Utilisation will increase.
TX Queue stopped because full: Message buffer (Ethernet Frames) in radio queue. If Radio cannot transmit due to
high noise, this will increment. When the buffer is full all new messages are dropped. Buffer size 150 messages.
Client:
Beacon Missed Interrupts: How many beacons (100msec) the Client has missed from the Access Point
TX Failed due to too many retries: This is how many frames that have been lost. Original Message + 7 Retries = 1
TX Failed due to too many retires. Each retry is sent within a few msec.
TX Failed / TX Antenna Profile = Frame Packet Loss Rate (How many undelivered as a %)
RX Failed due to bad CRC: This can be from any AP not only your own. If other Wi-Fi is around then this
number could be high due to other Encryption keys, weak signal etc.
RX Failed / RX Antenna Profile = RX Frame Error Rate (Note this can be high due to other wireless devices around.)
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Broadcast Notes: When Broadcast message is sent from CL – AP the AP will always ACK the Client. When
Broadcast Message is sent from AP – CL no ACK will be sent back.
Management Frames: Can be probes, Authenticate/ Associate messages, RTS Messages, Beacons, etc
Network Traffic Analysis
There are many devices and PC programs that will analyse performance of an Ethernet network. Freely available
programs such as Ethereal provide a simple cost effective means for more advanced analysis. By monitoring traffic
on the wired Ethernet, a better idea of regular traffic can be discovered.
Network Analysis programs make configuration of a filter for the 245U-E a simple task.
4.6 System Tools
The System Tools Page has a number of tools that help maintain the module firmware and configuration.
Configuration Summary
This option is used to save all the different configuration pages onto one page, for easy
viewing. Page can also be saved (using the File/Save As function on the drop File Menu) for
future reference and emailing module configuration details to Technical Support in the event
of any configuration problems.
TCP Throughput Test
Performs a Throughput Test. See section 4.4 ‖Throughput Test‖ above for details
Radio Path Test
Perform a Radio Path test without the use of a Laptop and get a visual indication of RSSI
and Throughput on the front panel LEDs.
Read Configuration File
This option will show the module configuration in XML format. This file can be saved for
future reference.
Write Configuration File
Any configuration XML files saved using the ―Read Configuration‖ above can be loaded
back into the module
Firmware Upgrade
This option is used for firmware upgrades. Load the file using the ―Browse‖ button and
when found press ―Send‖ which will load the file into the module. When completed press
―Reset‖ Firmware upgrade can be done locally or remotely via the radio.
System Log File
Shows an event log of the modules operation, used for diagnosing problems. Page can be
saved and emailed to ELPRO if requested. ―Clear System Log‖ will clear out the log file and
start fresh.
Reset
Resets the module
Factory Default
Configuration
Loads the Factory default configuration and resets. CAUTION – Doing this will overwrite
any current configuration
245U-E Wireless Ethernet User Manual
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4.7 Testing Radio Paths
Connection and Signal Strength
The general procedure for radio range testing a link is fairly simple. Configure two units to form a link using
automatic radio rates. Install the Access Point at a fixed location. Take a laptop computer and the Client to each of
the remote locations, and analyse the link using the Connectivity webpage. If a beacon is heard from the Access
Point, the Client will update its Connectivity webpage with the received signal strength of beacon messages from the
Access Point.
If the signal is strong enough, a link may be established, and the Connectivity webpage of the Access Point may be
opened. If the link is weak, the LINK led will go out, and the remote Connectivity webpage of the Access Point will
fail to load. Using this procedure, the signal strengths of units at both locations may be analysed, and traffic is sent
between the units whilst remote WebPages are opened.
Iperf Throughput Test
A more thorough test is to perform a throughput test which will check the amount of data that can be reliably
achieved via the Wireless link. There are a number of software tools that we can use to check the data throughput, i.e.
FTP - file transfer protocol, Iperf, Qcheck, etc.
The preferred application is ―Iperf‖ which has been configured in each modem and can be enabled to perform this
test. It can also be run externally using Laptops at either end of the radio link. The Iperf/Jperf application can be
downloaded from http://www.elprotraining.com/ethernet.html,
All of the above applications measure the raw data throughput and from this we can determine the amount of
interference from the measured and calculated data throughput levels.
The way ―iPerf‖ works is a Server is enabled at one end of the link and a Client at the other. The ―iPerf‖ Client will
then pass data over the link and calculate and display the throughput accordingly.
―iPerf‖ server can be run internally on the modem by enabling this feature on the Advanced Radio page of one of the
modems, see section 4.4 ―Throughput Test‖. It can also be run externally on a PC or laptop connected at each end of
the radio link. See Appendix E ―External Iperf Test‖ for a detailed procedure on how to use Iperf to externally check
radio data throughput.
The internal ―iPerf‖ is a basic cut down version of the standard ―iPerf‖ and should be used as a guide only. For a
more comprehensive test ―iPerf‖ should be run externally using Laptops or PCs at each end of the Wi-Fi link.
Internal Radio Test
The module also has an internal Radio Path test that will allow
you to perform a basic radio path test without the need for a
laptop or PC.
There are two tests that can be run, RSSI and Throughput;
Throughput can be disabled independently from RSSI
however disabling RSSI test will turn off both tests.
Typically, the Radio Path Test should be enabled at a modem
configured as a Client/Station
The Radio Path Test feature should not be enabled on a live system; it is intended for testing only.
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RSSI
The first test uses the RS232, LED to indicate the RSSI level from the Access Point. The LED will be green when the
RSSI to the Access Point is greater than the configured RSSI Strong Threshold or red when the RSSI to the AP is
greater than the configured RSSI Weak Threshold. If the RSSI to the AP is less than the RSSI Weak Threshold then
the RS232 LED will be off.
When the Radio Path Test is enabled, the OK LED will flash alternately between green and red indicating that it is in
a diagnostic mode.
Throughput
The second test is the Throughput Test which when enabled performs a basic throughput test between the AP and
Client. The configurable Remote Device IP Address should specify the IP Address of the AP
(Note that the on-board iperf server must be enabled at the AP prior to running this test).
The Throughput Test will run through a continuous cycle where data is transferred for 10 seconds, followed by 10
seconds of silence. The RS485 LED and the DIO LED are used as indicators of the throughput test. While data is
being transferred the DIO LED will be red, and while no data is being transferred the DIO LED will be off.
If the average throughput over the 10 second duration of the throughput test is greater than the configurable
Throughput High Threshold, then the RS485 LED will be green; otherwise if the throughput is greater than the
configurable Throughput Low Threshold then the RS485 LED will be red; if the measured throughput is less than the
Throughput Low Threshold then the RS485 LED will be off.
Radio Path Test can be accesses by selecting the link from the ―System Tools‖ page and then ticking the ―Enable
Radio Path Test‖ and entering in appropriate thresholds levels to indicate RSSI and Throughput and the IP address of
the Iperf Server (normally the Access Point).
The following screen shot shows the indications you will see using the Configuration above.
The OK Led will flash between Red and
Green which indicates the module is in a
diagnostic Radio Test Mode.
RS-232 Led is showing a green indication
which means the RSSI to the Access
Point is greater than -40dB. If the RS232
Led showed Red it would indicate the
RSSI level was greater than -60dB.
RS-485 Led is showing a green indication
which means the Throughput to the
Access Point is greater than 10 Mbps. If the Led showed a Red indication this would mean the throughput is between
10Mbps & 4 Mbps.
Radio Path Test can be accesses by selecting the link from the ―System Tools‖ page and then ticking the ―Enable
Radio Path Test‖ and entering in appropriate thresholds levels to indicate RSSI and Throughput.
Radio Path Test Settings
Enable Radio Path Test
Enables or disables the Radio Path Test.
RSSI Strong Threshold
Strong RSSI indication threshold
RSSI Weak Threshold
Weak RSSI indication threshold
Enable Throughput Test
Enables or disables the Throughput test (independent of Radio Path Test (RSSI)
Remote Device IP Address
IP Address of the Remote device that you wish to path test
Throughput High Threshold
High Throughput indication value. Generally configured with the desired
throughput level
Throughput Low Threshold
Low Throughput indication value.
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Note: Advanced configuration settings such as Serial or I/O Transfer should be disabled and if using
the Throughput Test, Iperf Server in the Advanced Radio Settings page on the Access Point must be
enabled.
4.8 Remote Configuration
Because a module configuration is viewed and changed in a web format (which uses TCP/IP protocol), you can view
or change the configuration of a remote module via the wireless link, provided the remote module already have a
wireless link established to the local 245U-E.
To perform remote configuration, connect a PC to the local module, run Internet Explorer and enter the IP address of
the remote unit (or device name if using DNS) - the configuration page of the remote module will be shown and
changes can be made.
Care must be taken if modifying the configuration of a module remotely. If the Radio Configuration is changed,
some changes made may cause loss of the radio link, and therefore the network connection.
It is advisable to determine the path of the links to the modules you wish to modify, and draw a tree diagram if
necessary. Modify the modules at the ―leaves‖ of your tree diagram. These will be the furthest away from your
connection point in terms of the number of radio or Ethernet links.
In a simple system, this usually means modifying the Client modules first and the Access Point last.
Configuring
PC or Laptop
Priority 4
Priority 3
Priority 2
Priority 2
Priority 1
Remote Configuration Priority
4.9 Internal Diagnostics Modbus Registers
There are a number of internal diagnostic registers that can be accessed via Modbus TCP/RTU that will help with
analysing and diagnosing the radio network. To access these register the Modbus Server will need to be enabled and
a Modbus Server address will need to be configured (See 3.15 ―Modbus I/O Transfer‖ for details on how this is
done).
After enabling the Modbus Client you can then access the following information by reading the corresponding
Modbus Address at the Server ID address.
Note: „wi0‟ is the normal default interface. If more interfaces are added by entering in virtual WDS
connections (either Client or AP) in section 3.17”Repeaters (WDS)” then they will take on the next
available interface number i.e. wi1, wi2, etc
Connection Information
Register
Module
Description
5000
Both
Total number Associated Stations
5001
Both
Current Radio Channel. See section 3.9 ―Radio Configuration‖ for channel details
5002
Both
Number Wireless Interfaces configured, includes Virtual Interfaces – wi1-wi10
5010
Both
Wireless Adaptor (wi0) - Link Status
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5011
Both
Wireless Adaptor (wi0) - Link Status Inverted
5012
Both
Wireless Adaptor (wi0) - Number Associated Stations for this interface
5013
AP Only
Wireless Adaptor (wi0) - Points to the starting register of the AP's Station List. First
interface (wi0) will always start at 5200 and dynamically enter data depending on the
number of STA’s. Remaining interfaces (wi1-wi10) will be entered after wi0 data.
Register 5023, 5033, etc will indicate starting location for each interface.
5014
STA Only
Wireless Adaptor (wi0) – RSSI & BGND of Rx message from AP e.g. Hex 5F5D =
5D for RSSI and 5F for BGND (Convert value from hex to dec and add a ―-― e.g. 5F
= -95dB)
5015
STA Only
Wireless Adaptor (wi0) - Transmit Data Rate from the Access Point
5016
STA Only
Wireless Adaptor (wi0) - MAC Address of the Access Point
5020-5026
As per 5010-5016
As per registers 5010-5016 but for the next Wireless Adaptor (wi1)
5030-5036
As per 5010-5016
As per registers 5010-5016 but for the next Wireless Adaptor (wi2)
5040-5046
As per 5010-5016
As per registers 5010-5016 but for the next Wireless Adaptor (wi3)
……etc
As per 5010-5016
As per registers 5010-5016 but for the next Wireless Adaptor (wi10)
5200
AP Only
RSSI of the Client (STA)
5201
AP Only
Transmit Data Rate to Client (STA)
5202
AP Only
MAC address of Client (STA)
…..etc
AP Only
Dynamic list of STA's Refer to register 5023, 5033, etc for starting register of each wi
interface
9999
Both
Reset module (enter FFFF to reset module)
Statistic
Register
Module
Description
4500
Both
Total data packets received on the interface
4502
Both
Received frames with antenna 1 (TX/RX)
4504
Both
Received frames with antenna 2 (RX)
4506
Both
Receiver / default antenna switches
4508
Both
Receive message failed due to bad CRC
4510
Both
Receive message failed due to decryption
4512
Both
Receive message failed due to MIC failure
4514
Both
Receive message failed due to FIFO overrun
4516
Both
Beacon missed interrupts
4518
Both
Total data packet sent on the interface
4520
Both
Transmit frames with antenna 1 (TX/RX)
4522
Both
Transmit frames with antenna 2 (RX)
4524
Both
Transmitter antenna switches
4526
Both
Transmitter on-chip retries
4528
Both
Transmit message failed due to too many retries
4530
Both
Transmit frames with alternate rate
4532
Both
Transmit frames with no ack marked (i.e. broadcast, multicast)
4534
Both
Management frames transmitted
4536
Both
Transmit frames with rts enabled
4538
Both
Transmit frames with cts enabled
4540
Both
Beacons transmitted
4542
Both
Beacon missed count
4544
Both
Beacon miss reset count
4546
Both
Transmit message failed due to no tx buffer (data)
4548
Both
Fatal hardware error interrupts
4550
Both
Receiver PHY error summary count
4552
Both
Transmitter queue stopped because it's full
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4.10 Utilities
“Ping”
Ping is a basic Internet program that lets you verify that a particular IP address exists and can accept requests. Ping is
used diagnostically to ensure that a host computer or device you are trying to reach is actually operating. If, for
example, a user can’t ping a host, then the user will be unable to send files to that host. Ping operates by sending a
packet of data to a designated address and waiting for a response. The basic operation of Ping can be performed by
following these steps in any Windows operating system.
Click on the Start Menu and select Run. Type in ―cmd‖ and enter, you should then see the command screen come up.
There will be a certain directory specified (unique to your own PC) with a flashing cursor at the end. At the cursor
type the word ―ping‖ leaving a space and the default IP address for the 245U-E at first start-up.
This command would be written as ―ping 192.168.0.118‖ then <enter> to send the ping command. The PC will reply
with an acknowledgement of your command and if your 245U-E is correctly configured your reply will look
something like this.
The screen shot below shows the response of the ―ping –t 192.168.0.118‖ command.
This –t command is used to repeatedly ping the specified node in the network, to cancel use ―Ctrl – C‖
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A good test for the network once it is first set up is to use ―ping‖ repeatedly from one PC’s IP address to the other
PC’s IP address. This gives a good indication of the network’s reliability and how responsive it is from point to point.
When you enter ―Ctrl-C‖ the program reports a packet sent-received-lost percentage.
”Ipconfig”
―ipconfig‖ can be used to show your current TCP/IP information, including your address, DNS server addresses,
adapter type and so on.
In the above example ipconfig was entered in the command prompt. The reply back shows the PC’s IP address,
Subnet mask and the gateway it is connected to.
Other ipconfig commands will return back more information. The hardware or MAC address of the computer may
be discovered using the command ipconfig /all.
Ipconfig /? lists all of the commands and their usages available for use.
“Arp”
Displays and modifies the IP-to-Physical address translation tables used by Address Resolution Protocol (ARP).
Once a remote computer has been pinged, this can be used to see the IP address & MAC address of the remote
computer. It will also show any other devices on the network that it may be connected to.
Command used for above screen shot is ―arp –a‖. It shows the PC’s direct IP address of 192.168.0.17 as also shown
before with ipconfig command. The other IP address shown with its associated MAC address is another device with
a connection to the PC. In this example it is the IP address of a PLC connected to the PC also.
”Route”
Route is used for the Router function. This is where you are joining 2 different networks together via the 245U-E
refer to Section 1.1
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Normally the 245U-E will only accept one routing rule, by using the Default Gateway IP Address on the Main
Network Page. If more than one routing rule is needed then a Routing Table is required, e.g. Multiple networks each
with a different IP range.
In the example below a routing rule needs to be entered into the Network A’s PC which will allow access between
Network A and Network B. This is can be entered at the command prompt as per instruction below.
Route PRINT will show all active routes on PC,
Route ADD will add a routing table to network,
route DELETE <destination netmask gateway interface> will delete the unwanted routing table
route CHANGE modifies an existing route.
An example of a routing table is shown for the configuration below.
Access Point Router Settings
Client Bridge Settings
Gateway IP 192.168.0.1
Gateway IP 192.168.2.51
Ethernet IP 192.168.0.191
Ethernet IP 192.168.2.50
Subnet Mask 255.255.255.0
Subnet Mask 255.255.255.0
Wireless IP 192.168.2.051
Wireless IP 192.168.2.50
Subnet Mask 255.255.255.0
Subnet Mask 255.255.255.0
In the Network A PC a routing rule is to be set.
This will allow Network A & B to have access to each other. This is entered under cmd prompt.
Route ADD 192.168.2.0 MASK 255.255.255.0 192.168.0.191
This says access everything on network B (192.168.2.0) with the Mask of 255.255.255.0 on Network A via the
Ethernet IP Interface 192.168.0.191
IP Address 192.168.2.0 will allow everything on this network to be shared by the router. When adding a routing
table you will need to enter this in. Once entered in the Router will determine whether to pass information over the
router if it is addressed to do so or not. For added security MAC address filtering could be added as mentioned
earlier in Section 3.
Network A Settings
Network B Settings
IP Address 192.168.0.17
IP Address 192.168.2.201
Subnet Mask 255.255.255.0
Subnet Mask 255.255.255.0
Gateway IP 192.168.0.1
Gateway IP 192.168.2.51
NETWORK B
Router
NETWORK A
Access
Point
Client
Bridge
192.168.0.17
Gateway IP 192.168.0.1
192.168.2.201
Gateway IP 192.168.2.51
Ethernet IP 192.168.0.191
Wireless IP 192.168.2.51
Gateway IP 192.168.0.1
Ethernet IP 192.168.2.50
Wireless IP 192.168.2.50
Gateway IP 192.168.2.51
PC PC
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Chapter 5 SPECIFICATIONS
GENERAL
EMC specification
EN 300 683
FCC Part 90
Radio specification
EN 300 328
FCC Part 15.247, RSS 210
Housing
114 x 140 x 30mm, 4.5 x 5.5 x 1.2 inch
Powder-coated, extruded aluminium
DIN rail mount
Terminal blocks
Removable
Suitable for 12 gauge (2.5mm2) conductors
LED indication
Module Status, Serial RX and TX, Radio RX and TX, Radio Link, Ethernet Activity / Link
Operating Temperature
-40 to +60°C, -40 to +140 F
0 – 99% RH non-condensing
POWER SUPPLY
Nominal supply
9 to 30VDC
Overvoltage and reverse voltage protected
Average current drain
245U-E-G = 290 mA @ 12V
245U-E-A = 300 mA @ 12V
245U-E-G = 150mA @ 24VDC
245U-E-A = 160mA @ 24VDC
Current drain when
transmitting (400mW)
245U-E-G = 340 mA @ 12V
245U-E-A = 410 mA @ 12V
245U-E-G = 180mA @ 24VDC
245U-E-A = 210mA @ 24VDC
Ethernet Port
10/100 BaseT
RJ45
Standard
IEEE 802.3 compliant
Bridge/router, Access point/ client functionality
RADIO TRANSEIVER
Transmit power
Model
Maximum Power
(Power may be limited by
country specific configuration)
245U-E-G
1-24 Mb/s: 400mW (+26 dBm)
36 Mb/s: 250mW(+24 dBm)
48 Mb/s: 160mW(+22 dBm)
54 Mb/s: 125mW(+21 dBm)
(Power may be limited by
country specific configuration)
245U-E-A
6-24 Mb/s: 400mW (+26 dBm)
36 Mb/s: 250mW(+24 dBm)
48 Mb/s: 160mW(+22 dBm)
54 Mb/s: 125mW(+21 dBm)
Channels 2.4 GHz
13 x 5MHz Spacing
First channel centre at 2.412 GHz
Channels 5 GHz
12 fixed channels (3 Turbo Mode) or Auto
Channel/Group selection
Auto Channel/Group selection utilises DFS
depending on Group selection
Receiver sensitivity
Model
Receiver Sensitivity
(8% FER)
245U-E-G
-97dBm @ 1Mb/s, -94dBm @ 6Mb/s,
-90dBm @ 18Mb/s, -74dBm @ 54Mb/s
245U-E-A
-94dBm @ 6Mb/s, -90dBm @ 18Mb/s, -74dBm @
54Mb/s
Antenna Connector
2 x Female SMA coaxial
Two connectors for signal diversity or High gain
receive antenna.
Wireless data rate –
configurable
1 to 54Mb/s (245U-E-G), Turbo – 108Mb/s
6 to 54Mb/s 245U-E-A), Turbo – 108Mb/s
―Auto‖ function determines fastest rate possible
SERIAL PORTS
RS232 Port
DB9 female DCE
RTS/CTS/DTR/DCD hardware signals provided
RS485 Port
2 pin terminal block
Max distance 4000’ / 1.2 km
Data rate (bit/sec) -
configurable
1200, 2400, 4800, 9600, 14400, 19200,
38400, 57600, 76800, 115200
7 or 8 data bits, Stop/start/parity bits configurable
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SYSTEM PARAMETERS
System address (ESSID)
1 to 31 character text string
Maximum # Clients per AP
127 clients per Access Point
Wireless data encryption
WEP (64bit and 128bit), WPA-PSK (TKIP), WPA-PSK (AES), WPA2-PSK(AES),
WPA-PSK/WPA2-PSK, WPA Enterprise (EAP method - PEAP / MSCHAPv2)
User Configuration
Via embedded web page via RS232 commands
Diagnostics LED‟s
Power / OK, Ethernet Link, Activity, 100mb/s, Radio Link, RX, Rx Weak Signal, TX, Serial
RX/TX, Digital I/O Input / Output status
Other
RSSI measurement in dBm
Connectivity Information
System Log file
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Appendix A FIRMWARE UPGRADE
Determine which firmware version is present in the module to be upgraded by viewing the index webpage of the
module.
Firmware versions 1.0.3 and later may be upgraded via the configuration web pages. This upgrade can be done
locally with a PC connected directly to the module, or remotely over a working radio link. For remote upgrade,
it is advisable to reduce radio traffic over the link from other devices, as much as possible. If necessary, create a
temporary separate radio network to perform the upgrade to remote modules. Please refer to the ―Web based
Upgrade‖ section for the upgrade procedure.
Web based Upgrade
Web based firmware upgrade is available from the System tools page by selecting ―firmware upgrade‖.
Firmware upgrade is performed by uploading a ―patch‖ file which is specific to the currently installed firmware
version. If the device firmware version has fallen multiple versions behind the desired version, it may be
necessary to upload multiple ―patch‖ files. Once the patch files are uploaded, reset the module to perform the
firmware upgrade. You will receive more detailed instructions if it is necessary to upgrade the module firmware.
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Appendix B GLOSSARY
ACK
Acknowledgment.
Access Point
An access point connects wireless network stations (or clients) to other stations within the wireless
network and also can serve as the point of interconnection between the wireless network and a wired
network. Each access point can serve multiple users within a defined network area. Also known as a base
station.
Antenna Gain
Antennae don’t increase the transmission power, but focus the signal more. So instead of transmitting in
every direction (including the sky and ground) antenna focus the signal usually either more horizontally
or in one particular direction. This gain is measured in decibels
Bandwidth
The maximum data transfer speed available to a user through a network―‖.
Bridge
A bridge is used to connect two local area networks together. Bridges are typically used to connect
wireless networks to wired networks. Typically, bridges will transfer messages between networks only
when the message destination is on the other network. Messages that are destined for the same network as
they originated on are not passed to the other network, therefore reducing traffic on the entire network.
Collision
avoidance
A network node procedure for proactively detecting that it can transmit a signal without risking a collision
with transmissions from other network nodes.
Client / Sta /
Station
A device on a network that gains access to data, information, and other devices through a Server (Access
Point).
Crossover cable
A special cable used for networking two computers without the use of a hub. Crossover cables may also
be required for connecting a cable or DSL modem to a wireless gateway or access point. The cable is
wired so that the signals ―crossover‖, connecting transmit signal on one side to receiver signals on the
other.
CSMA/CA
Carrier Sense Multiple Access/Collision Avoidance is a "listen before talk" method of minimizing (but
not eliminating) collisions caused by simultaneous transmission by multiple radios. IEEE 802.11 states
collision avoidance method rather than collision detection must be used, because the standard employs
half duplex radios—radios capable of transmission or reception—but not both simultaneously. Unlike
conventional wired Ethernet nodes, a WLAN station cannot detect a collision while transmitting. If a
collision occurs, the transmitting station will not receive an ACKnowledge packet from the intended
receive station. For this reason, ACK packets have a higher priority than all other network traffic. After
completion of a data transmission, the receive station will begin transmission of the ACK packet before
any other node can begin transmitting a new data packet. All other stations must wait a longer pseudo
randomized period of time before transmitting. If an ACK packet is not received, the transmitting station
will wait for a subsequent opportunity to retry transmission.
CSMA/CD
Carrier Sense Multiple Access/Collision Detection is the access method used on an Ethernet network. A
network device transmits data after detecting that a channel is available. However, if two devices transmit
data simultaneously, the sending devices detect a collision and retransmit after a random time delay.
DHCP
Dynamic Host Configuration Protocol A utility that enables a server to dynamically assign IP addresses
from a predefined list and limit their time of use so that they can be reassigned. Without DHCP, an IT
Manager would have to manually enter in all the IP addresses of all the computers on the network. When
DHCP is used, whenever a computer logs onto the network, it automatically gets an IP address assigned
to it.
Dial-up
A communication connection via the standard telephone network, or Plain Old Telephone Service
(POTS).
DNS
Domain Name Service A program that translates URLs to IP addresses by accessing a database
maintained on a collection of Internet servers. The program works behind the scenes to facilitate surfing
the Web with alpha versus numeric addresses. A DNS server converts a name like mywebsite.com to a
series of numbers like 107.22.55.26. Every website has its own specific IP address on the Internet.
DSL
Digital Subscriber Line Various technology protocols for high-speed data, voice and video transmission
over ordinary twisted-pair copper POTS (Plain Old Telephone Service) telephone wires.
Encryption key
An alphanumeric (letters and/or numbers) series that enables data to be encrypted and then decrypted so it
can be safely shared among members of a network. WEP uses an encryption key that automatically
Appendix B 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 91 91
encrypts outgoing wireless data. On the receiving side, the same encryption key enables the computer to
automatically decrypt the information so it can be read. Encryption keys should be kept secret
Firewall
A device or computer program that keeps unauthorized users out of a private network. Everything
entering or leaving a system's internal network passes through the firewall and must meet the system's
security standards in order to be transmitted. Often used to keep unauthorized people from using systems
connected to the Internet.
Hub
A multiport device used to connect PCs to a network via Ethernet cabling or via 802.11. Wired hubs can
have numerous ports and can transmit data at speeds ranging from 10 Mbps to multi-Gigabyte speeds per
second. A hub transmits packets it receives to all the connected ports. A small wired hub may only
connect 4 computers; a large hub can connect 48 or more.
Hz
Hertz. The international unit for measuring frequency, 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 US
electrical power frequency is 60 Hz, the AM broadcast radio frequency band is 535—1605 kHz, the FM
broadcast radio frequency band is 88—108 MHz, and wireless 802.11b/g LANs operate at 2.4 GHz.
IEEE
Institute of Electrical and Electronics Engineers, New York, www.ieee.org. A membership organization
that includes engineers, scientists and students in electronics and allied fields. It has more than 300,000
members and is involved with setting standards for computers and communications.
Infrastructure
mode
An 802.11 setting providing connectivity to an AP. As compared to Ad-Hoc mode, whereby 802.11
devices communicate directly with each other, clients set in Infrastructure Mode all pass data through a
central AP. The AP not only mediates wireless network traffic in the immediate neighbourhood, but also
provides communication with the wired network. See Ad-Hoc and AP.
I/O
Input / Output. The term used to describe any operation, program or device that transfers data to or from a
computer.
Internet
appliance
A computer that is intended primarily for Internet access is simple to set up and usually does not support
installation of third-party software. These computers generally offer customized web browsing, touchscreen navigation, e-mail services, entertainment and personal information management applications.
IP
Internet Protocol. A set of rules used to send and receive messages across local networks and the Internet.
IP telephony
Technology that supports voice, data and video transmission via IP-based LANs, WANs, and the Internet.
This includes VoIP (Voice over IP).
IP address
A 32-bit number that identifies each sender or receiver of information that is sent across the Internet. An
IP address has two parts: an 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.
IPX-SPX
Internetwork Packet Exchange, a networking protocol used by the Novell NetWare operating systems.
Like UDP/IP, IPX is a datagram protocol used for connectionless communications. Higher-level
protocols, such as SPX and NCP, are used for additional error recovery services. Sequenced Packet
Exchange, SPX, a transport layer protocol (layer 4 of the OSI Model) used in Novell Netware networks.
The SPX layer sits on top of the IPX layer (layer 3) and provides connection-oriented services between
two nodes on the network. SPX is used primarily by client/server applications.
ISDN
A type of broadband Internet connection that provides digital service from the customer's premises to the
dial-up telephone network. ISDN uses standard POTS copper wiring to deliver voice, data or video.
ISO Network
Model
A network model developed by the International Standards Organization (ISO) that consists of seven
different levels, or layers. By standardizing these layers, and the interfaces in between, different portions
of a given protocol can be modified or changed as technologies advance or systems requirements are
altered. The seven layers are: Physical , Data Link, Network, Transport, Session, Presentation,
Application.
LAN
Local Area Network. A system of connecting PCs and other devices within the same physical proximity
for sharing resources such as an Internet connections, printers, files and drives.
Receive
Sensitivity
The minimum signal strength required to pick up a signal. Higher bandwidth connections usually have
less receive sensitivity than lower bandwidth connections.
Router
A device that forwards data from one WLAN or wired local area network to another.
SNR
Signal to Noise Ratio. The number of decibels difference between the signal strength and background
noise.
245U-E Wireless Ethernet User Manual
Page 92 Dec 2011
Transmit Power
The power usually expressed in mW or dBm that the wireless device transmits at.
MAC Address
Media Access Control address. A unique code assigned to most forms of networking hardware. The
address is permanently assigned to the hardware, so limiting a wireless network's access to hardware -such as wireless cards -- is a security feature employed by closed wireless networks. But an experienced
hacker -- armed with the proper tools -- can still figure out an authorized MAC address, masquerade as a
legitimate address and access a closed network.
Every wireless 802.11 device has its own specific MAC address hard-coded into it. This unique identifier
can be used to provide security for wireless networks. When a network uses a MAC table, only the 802.11
radios that have had their MAC addresses added to that network's MAC table will be able to get onto the
network.
NAT
Network Address Translation: A network capability that enables a number of computers to dynamically
share a single incoming IP address from a dial-up, cable or xDSL connection. NAT takes the single
incoming IP address and creates new IP address for each client computer on the network.
NIC
Network Interface Card. A type of PC adapter card that either works without wires (Wi-Fi) or attaches to
a network cable to provide two-way communication between the computer and network devices such as a
hub or switch. Most office wired NICs operate at 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet) or
10/100 Mbps dual speed. High-speed Gigabit and 10 Gigabit NIC cards are also available. See PC Card.
Proxy Server
Used in larger companies and organizations to improve network operations and security, a proxy server is
able to prevent direct communication between two or more networks. The proxy server forwards
allowable data requests to remote servers and/or responds to data requests directly from stored remote
server data.
RJ-45
Standard connectors used in Ethernet networks. RJ-45 connectors are similar to standard RJ-11 telephone
connectors, but RJ-45 connectors can have up to eight wires, whereas telephone connectors have four.
Server
A computer that provides its resources to other computers and devices on a network. These include print
servers, Internet servers and data servers. A server can also be combined with a hub or router.
Site survey
The process whereby a wireless network installer inspects a location prior to installing a wireless network.
Site surveys are used to identify the radio- and client-use properties of a facility so that access points can
be optimally placed.
SSL
Secure Sockets Layer. A commonly used encryption scheme used by many online retail and banking sites
to protect the financial integrity of transactions. When an SSL session begins, the server sends its public
key to the browser. The browser then sends a randomly generated secret key back to the server in order to
have a secret key exchange for that session
Sub network or
Subnet
Found in larger networks, these smaller networks are used to simplify addressing between numerous
computers. Subnets connect together through a router.
Switch
A type of hub that efficiently controls the way multiple devices use the same network so that each can
operate at optimal performance. A switch acts as a networks traffic cop: rather than transmitting all the
packets it receives to all ports as a hub does, a switch transmits packets to only the receiving port.
TCP
Transmission Control Protocol. A protocol used along with the Internet Protocol (IP) to send data in the
form of individual units (called packets) between computers over the Internet. While IP takes care of
handling the actual delivery of the data, TCP takes care of keeping track of the packets that a message is
divided into for efficient routing through the Internet. For example, when a web page is downloaded from
a web server, the TCP program layer in that server divides the file into packets, numbers the packets, and
then forwards them individually to the IP program layer. Although each packet has the same destination
IP address, it may get routed differently through the network. At the other end, TCP reassembles the
individual packets and waits until they have all arrived to forward them as single message.
TCP/IP
The underlying technology behind the Internet and communications between computers in a network. The
first part, TCP, is the transport part, which matches the size of the messages on either end and guarantees
that the correct message has been received. The IP part is the user's computer address on a network. Every
computer in a TCP/IP network has its own IP address that is either dynamically assigned at startup or
permanently assigned. All TCP/IP messages contain the address of the destination network as well as the
address of the destination station. This enables TCP/IP messages to be transmitted to multiple networks
(subnets) within an organization or worldwide.
VoIP
Voice Over Internet Protocol. Voice transmission using Internet Protocol to create digital packets
Appendix B 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 93 93
distributed over the Internet. VoIP can be less expensive than voice transmission using standard analog
packets over POTS (Plain Old Telephone Service).
VPN
Virtual Private Network. A type of technology designed to increase the security of information transferred
over the Internet. VPN can work with either wired or wireless networks, as well as with dial-up
connections over POTS. VPN creates a private encrypted tunnel from the end user's computer, through
the local wireless network, through the Internet, all the way to the corporate servers and database.
WAN
Wide Area Network. A communication system of connecting PCs and other computing devices across a
large local, regional, national or international geographic area. Also used to distinguish between phonebased data networks and Wi-Fi. Phone networks are considered WANs and Wi-Fi networks are
considered Wireless Local Area Networks (WLANs).
WEP
Wired Equivalent Privacy. Basic wireless security provided by Wi-Fi. In some instances, WEP may be all
a home or small-business user needs to protect wireless data. WEP is available in 40-bit (also called 64bit), or in 108-bit (also called 128-bit) encryption modes. As 108-bit encryption provides a longer
algorithm that takes longer to decode, it can provide better security than basic 40-bit (64-bit) encryption.
Wi-Fi
Wireless Fidelity: An interoperability certification for wireless local area network (LAN) products based
on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard.
245U-E Wireless Ethernet User Manual
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Appendix C CHANNELS
802.11b/g
Channel
Frequency
(MHz)
North
America
Europe
Australia
Japan
Most of
world
1
2412
Yes
Yes
Yes
Yes
Yes
2
2417
Yes
Yes
Yes
Yes
Yes
3
2422
Yes
Yes
Yes
Yes
Yes
4
2427
Yes
Yes
Yes
Yes
Yes
5
2432
Yes
Yes
Yes
Yes
Yes
6
2437
Yes
Yes
Yes
Yes
Yes
7
2442
Yes
Yes
Yes
Yes
Yes
8
2447
Yes
Yes
Yes
Yes
Yes
9
2452
Yes
Yes
Yes
Yes
Yes
10
2457
Yes
Yes
Yes
Yes
Yes
11
2462
Yes
Yes
Yes
Yes
Yes
12
2467
No
Yes
Yes
Yes
Yes
13
2472
No
Yes
Yes
Yes
Yes
14
2484
No
No
No
.11b only
No
802.11b/g Turbo
Channel
Frequency
(MHz)
North
America
Europe
Australia
Japan
Most of
world
6
2437
Yes
Yes
Yes
Yes
Yes
Appendix C 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 95 95
802.11a – Maximum Radio Transmitter Power
Channel
Freq
(MHz)
Europe max
TX Power
(Master)
Europe max
TX Power
(Slave)
Australia
max TX
Power
NZ max
TX
Power
USA max
TX
Power
36
5180
23 dBm
23 dBm
23 dBm
23 dBm
17 dBm
40
5200
23 dBm
23 dBm
23 dBm
23 dBm
17 dBm
44
5220
23 dBm
23 dBm
23 dBm
23 dBm
17 dBm
48
5240
23 dBm
23 dBm
23 dBm
23 dBm
17 dBm
52
5260
20 dBm
20 dBm
20 dBm
20 dBm
24 dBm
56
5280
20 dBm
20 dBm
20 dBm
20 dBm
24 dBm
60
5300
20 dBm
20 dBm
20 dBm
20 dBm
24 dBm
64
5320
20 dBm
20 dBm
20 dBm
20 dBm
24 dBm
100
5500
26 dBm
20 dBm
20 dBm
20 dBm
24 dBm
104
5520
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
108
5540
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
112
5560
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
116
5580
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
120
5600
26 dBm
20 dBm
n/a
20 dBm
24 dBm
124
5620
26 dBm
20 dBm
n/a
20 dBm
24 dBm
128
5640
26 dBm
20 dBm
n/a
20 dBm
24 dBm
132
5660
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
136
5680
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
140
5700
26 dBm
20 dBm
24 dBm
20 dBm
24 dBm
149
5745
n/a
n/a
26 dBm
26 dBm
26 dBm
153
5765
n/a
n/a
26 dBm
26 dBm
26 dBm
157
5785
n/a
n/a
26 dBm
26 dBm
26 dBm
161
5805
n/a
n/a
26 dBm
26 dBm
26 dBm
165
5825
n/a
n/a
26 dBm
26 dBm
26 dBm
802.11a Turbo - Maximum Radio Transmitter Power
Channel
Freq
(MHz)
Europe max
(Master)
Europe max
(Slave)
Australia
max
NZ max
USA
max
42
5210
23 dBm
23 dBm
23 dBm
23 dBm
17 dBm
152
5755
n/a
n/a
26 dBm
26 dBm
26 dBm
160
5795
n/a
n/a
26 dBm
26 dBm
26 dBm
245U-E Wireless Ethernet User Manual
Page 96 Dec 2011
Appendix D 802.11a & TX Power
Band &
Frequency
EU &
South Africa
USA
Australia
New Zealand
U-NII
Band
Frequency
(MHz)
No DFS
DFS
No DFS
DFS
No DFS
DFS
No DFS
DFS
1
5150-5250
200 mW
–
50 mW
–
200 mW
–
200 mW
–
2
5250-5350
–
100 mW
–
500 mW
–
100 mW
–
100 mW
3
5470-5725
–
500 mW
–
500 mW
–
250 mW
–
500 mW
4
5725-5825
– – 4 W – 4 W – 4 W
–
All Power levels are shown as EIRP (Effective Isotropic Radiated Power)
dB to mWatt Conversion
Watts
dBm
Watts
dBm
10 mW
10 dB
200 mW
23 dB
13 mW
11 dB
316 mW
25 dB
16 mW
12 dB
398 mW
26 dB
20 mW
13 dB
500 mW
27 dB
25 mW
14 dB
630 mW
28 dB
32 mW
15 dB
800 mW
29 dB
40 mW
16 dB
1.0 W
30 dB
50 mW
17 dB
1.3 W
31 dB
63 mW
18 dB
1.6 W
32 dB
79 mW
19 dB
2.0 W
33 dB
100 mW
20 dB
2.5 W
34 dB
126 mW
21 dB
3.2 W
35 dB
158 mW
22 dB
4.0 W
36 dB
Appendix E 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 97 97
Appendix E External Iperf Test
This Appendix shows how to set up and use the Iperf application to test the throughput of Ethernet Modems.
Iperf is a tool used to measure the throughput and quality of a network link. Jperf is used in conjunction with
Iperf and displays the Iperf data results graphically. This instruction covers both Iperf and Jperf, it does not
cover the setup and configuration of the modems. Details of this can be found in previous sections.
Materials
2 x Ethernet Modems configured as a bridge
2 x PC Computers with Ethernet Ports
Suitable Power Supplies for the Ethernet Modems
Straight through Ethernet cables
Iperf / Jperf Application
Installation
The Application can be downloaded from the following link http://www.elprotraining.com/ethernet.html,
download and save to a location on your PC.
Extract to zip file to the ROOT directory on your PC, i.e. C:\. This folder contains the main Iperf application as
well as the Jperf graphical interface.
Copy this folder to the 2nd PC or download to the second PC and extract as per above instructions.
Iperf Applications
The Iperf /Jperf application needs to be run on the PC or laptop at each end of the wireless link that is to be
tested.
At the Server PC open a Command prompt by selecting Windows Start/run and enter ―CMD‖.
When command prompt appears we need to set the directory to where the Iperf application resides, i.e. where it
was saved above, and from here run the Iperf server command ―iperf – s‖. See Figure 1
Figure 1
Note: If you get a security pop up on PC select Unblock for the application to run.
Iperf server application is now running and waiting for a Client connection.
On the Client PC open up a CMD prompt and change the directory to jperf-2.0.2\bin as performed above for the
server.
This time enter the Iperf command to start the client communication to the server. ―Iperf –c <IP address of
Server PC> -w 65535. See Figure 2
245U-E Wireless Ethernet User Manual
Page 98 Dec 2011
Figure 2
This will run a test over the Wi-Fi Link to the Server PC and report back results as seen in Figure 3.
These results show the Bandwidth (Throughput) of the test as 16.2Mbits/sec.
Figure 3
Using the Theoretical throughput calculations in Table 1 you can compare the results with the measured to give
an indication of the difference between expected and measured. Remembering that the theoretical calculations
are best case possible results
240U-E
245U-E-G
245U-E-A
945U-E
(20Mhz)
905U-E
805U-E
54Mbps
27Mbps
27Mbps
27Mbps
11Mbps
5Mbps
5Mbps
5Mbps
5Mbps
1Mbps
500Kbps
500Kbps
500Kbps
500Kbps
200Kbps
80Kbps
100Kbps
40Kbps
78Kbps
37Kbps
19.2Kbps
7.8Kbps
6.9Kbps
Table 1
In the command line for the Client mapping we established the Server IP address followed by the –w 65535, -w
is the window size and the maximum TCPIP window size is 65535bytes.
Another entry that can be added is –t <seconds> to run the test for a specific time period. Example of this is in
figure 5 where the same test is run for 30 seconds.
Appendix E 245U-E Wireless Ethernet
man_245UE_V1.8.1.docx Page 99 99
JPerf Application
Jperf is a graphical interface that runs over the top of Iperf. It will display a graph result from the Iperf test.
To run Jperf open a CMD prompt and change to the ―jperf-2.0.2: directory and run the ―Jperf‖ application as
shown in Figure 4. The CMD screen will disappear and the Jperf Screen will appear as seen in Figure 5.
Figure 4
Figure 5
When Jperf screen appears select Client Mode, enter in IP address of the Server PC; leave Port as default and
press Run Iperf button. The test will run again and the Bandwidth (Throughput) display will show results of the
test.
Note: Jperf runs using Java technology and depending on PC setup further installation of Java software may be
required.
245U-E Wireless Ethernet User Manual
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Appendix F GNU Free Doc Licence
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License
is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This General
Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it.
(Some other Free Software Foundation software is covered by the GNU Lesser General Public License instead.) You can apply it to your
programs, too.
When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if
you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These
restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have.
You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free
software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original,
so that any problems introduced by others will not reflect on the original authors' reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will
individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be
licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and modification follow.
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION0.
This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under
the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program"
means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either
verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term
"modification".) Each licensee is addressed as "you".
Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running
the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program
(independent of having been made by running the Program). Whether that is true depends on what the Program does.
1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices
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You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
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These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can
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