AvaLAN AW900R2-PAIR User`s manual

900 MHz Wireless RS-232 Module
Evaluation Kit
Industrial-grade, long-range wireless systems
AW900R2-EVAL User’s Manual
Thank you for your purchase of the AW900R2-EVAL Wireless RS-232 Module Evaluation
If you have any questions when configuring your AvaLAN system, the best place to
get answers is to visit www.avalanwireless.com. You will also find the latest updates
If more assistance is needed, send email to support@avalanwireless.com.
To speak to a live technician, please call technical support at the number below
during normal business hours.
Limited Warranty
This product is warranted to the original purchaser for normal use for a period of 360 days
from the date of purchase. If a defect covered under this warranty occurs, AvaLAN will repair
or replace the defective part, at its option, at no cost. This warranty does not cover defects
resulting from misuse or modification of the product.
© 2010 by AvaLAN Wireless Systems Inc. All rights reserved.
Revision 06.23.2010
125A Castle Drive
Madison, AL 35758
Sales: (866) 533-6216
Technical Support: (650) 384-0000
Customer Service: (650) 641-3011
Fax: (650) 249-3591
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User’s Manual
Operational summary
RS-232 is a point-to-point serial data connection that requires just three wires:
Transmit Data, Receive Data and Ground. Because there is no handshake involved,
both ends must be configured for matching data timing and protocol or communication will not occur. Also, it is possible to lose data if the receiving device cannot
keep up with the sending device. The AW900R2 supports data rates from 9600 Baud
to 115,200 Baud and has a 4 KB data buffer. When properly configured, a pair of
AW900R2 modules behave just like an RS-232 cable but without the length constraint and without a physical wire.
Configuring a wireless link with the AW900R2 requires the establishment of six
• One radio must be configured as the Access Point (AP) and the other one must
be configured as the Subscriber Unit (SU).
• Both radios must share a common Network Name, a 32-bit identifier.
• Both radios must share a common 128-bit encryption key.
• The AP and SU must agree on which radio frequency channel they are using.
This can be manually set or allowed to change automatically.
• The serial port settings: Baud rate, number of data and stop bits and sense of
Parity bit, must match between each radio and the RS-232 device wired to it,
although the radio link may have different settings at each end.
• The AP and SU must share a common set of tuning parameters: Next Byte
Delay, Minimum Packet Size and Maximum Packet Size.
AW900R2 modules are configured through a built-in USB port with a utility program
from AvaLAN. The LED display on the module PC board is also a very useful indicator
of the condition of the wireless connection.
The access point (AP) automatically scans for the best of the 12 available radio
frequency channels, encrypts RS-232 data received, and transmits it wirelessly to
the subscriber unit (SU). The AP is constantly monitoring the radio link and can
automatically change the channel if performance is degraded due to interference.
If two AP units are very close to one another, they may interfere if operating on
adjacent frequency channels. Place them at least 10 feet apart or manually select
non-adjacent channels for their operation. Also, the SU should be placed at least 10
feet from the AP to avoid overloading the radio’s receiver.
At each end of the wireless link, the RS-232 device wired to the AW900R2 must have
its transmit signal connected to the module’s receive and vice versa. Mis-wiring will
not cause damage, but will prevent communication.
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AW900R2-EVAL User’s Manual
Electrical Connections
The AW900R2-EVAL 900 MHz Wireless RS-232 Module Evaluation Kit contains two
each of the following items:
• AW900R2 Wireless Ethernet Modules
• AW2-900 Omnidirectional Antennas
• AW-P8 Antenna to Radio Connectors
• 20” USB to Mini-USB Adapter Cables
• 120VAC to 6 VDC Wall Hanger Power Supplies
Additional quantities of any of these components may be purchased from AvaLAN
Wireless or our distributors.
To power up a radio module, make connections to it as shown in this diagram:
PC with
Windows XP
or later
900 MHz
Status LEDs
Plain black wire
White-striped wire
Reset Switch
(cycles power)
The USB connection is not needed after the link is
configured and operating normally. If the USB cable
is connected, the module can draw its power from
it. (A high-power USB port is required.)
Provide some physical separation between two radio module antennas — at least
ten feet. If their antennas are in close proximity, the module radio receivers will be
overloaded, causing degradation in the bit error rate and slower link performance.
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Physical Dimensions
66 mm
23 mm
18 mm
55 mm
63 mm
18 mm
58 mm
15 mm
33 mm
25 mm
900 MHz Channels
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Center Frequency
Auto Mode
903.12500 MHz
905.20833 MHz
907.29167 MHz
909.37500 MHz
911.45833 MHz
913.54167 MHz
915.62500 MHz
917.70833 MHz
919.79167 MHz
921.87500 MHz
923.95833 MHz
926.04167 MHz
AW900R2-EVAL User’s Manual
Setting or changing the configuration (Baud rate, etc.) of the AW900R2 module is
done via the USB interface on the board. Follow these steps:
1. The PC that you will connect via USB to the module must have a USB 2.0 or later
port available and be running MS Windows XP or later. In addition, three critical
pieces of software must be installed; a driver, a utility and a dll.
2. Your PC requires a virtual COM port driver to allow communication with the USB
interface chip in the module. This driver may be downloaded from the chip manufacturer’s website, http://www.ftdichip.com. On their site menu, select “Drivers”
and “VCP” (Virtual COM Port). Next, choose the driver corresponding to your PC’s
operating system and our chip, which is an FT232R. At this manual’s writing, the
correct choice was Driver Version 2.06.02, dated 31 March 2010. Download the zip
file from their site. You would also be advised to download the installation guide
for your operating system, available from the link at the top of the driver selection
page. Extract the driver zip file to a folder of your choice, connect the module to
your PC using the supplied USB cable and follow the instructions in the installation
guide. Once you are successful, you should be able to navigate to your device manager and see something like this in the “Ports” section:
The device labeled “USB Serial Port (COM6) is the connection to the AW900R2 module. Windows chooses which COM port number to assign, so yours is unlikely to be
COM6. In fact, every time you plug and unplug the USB or restart your computer,
the assigned COM port number will probably be different. So your first step when
up and running should be to call up the device manager and find out what the right
port number is.
3. Next, you will need a configuration utility and its associated dll file from AvaLAN.
Go to our website, http://www.avalanwireless.com. Navigate to “Support” then
“Downloads.” Choose the “AvaLAN Evk Utility Lite” file and download the zip file.
This zip archive contains two files, EvkUtilityLite.exe and ZedGraph.dll. Extract both
of these to the same folder of your choice. The utility does not use the Windows
registry and can be placed anywhere, but the dll must be in the same folder. If Evk
Utility Lite refuses to run, check first to be sure the dll file is there.
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4. Run EvkUtilityLite.exe and you should see a window like this:
5. Use the dropdown menu labeled “Boot Config Serial Port” to select the virtual
COM port connected to your AW900R2 module. Note that the list is populated only
when EvkUtilityLite first starts. If you change your cable connection or plug in another module, restart the utility to see the changes. Next click the “Get” button
to fetch the current configuration from the module. 6. If you are satisfied with the
module’s configuration and status, stop here. If changes are needed, return to the
Boot Configuration tab and prepare to change the configuration of the module. Here
is an explanation of the parameters that may be set on the Boot Configuration page:
Radio Configuration
Radio buttons to select whether this module is the master or the client of
the pair. Each RS-232 wireless link must have an Access Point at one end and
a Subscriber Unit at the other.
Number of Subscriber
Units/Subscriber ID
A two digit number, leading zero required, that must be set to “01” for
these AW900R2 modules. (Other numbers are needed for multi-drop RS-485
Channel 00-12
The RF channel for the module. The frequencies corresponding to each channel are shown in the table on page 5. Choose “00” for automatic channel
selection or set “01” to “12” for a fixed choice.
Network Name
A 32-bit value (8 Hex digits, 0 to 9 and A to F) that must be the same for the
two radio modules of the link. If you have multiple links operating in the
same vicinity, give each link a unique value.
AES Private Key
A 128-bit value (32 Hex digits) that must be the same for the two radio modules in the link. This key is used to encrypt the transmitted data and decrypt
the received data.
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Serial Port Settings
These settings must match the RS-232 device wired to the module
Baud Rate
Drop down menu providing 6 choices from 9600 Baud to 115,200 Baud (serial
data rate).
Data Bits
Selectable 7 or 8 data bits (8 is the most common choice)
Selectable among “none”, “even”, “odd”, “mark” or “space” (“none” is the
most common choice)
Stop Bits
Select 1 or 2 stop bits (1 is the most common choice)
Tuning Parameters
These affect the behavior of the RF packet transmissions relative to the
incoming serial data. We suggest leaving these at the default values unless
the nature of the serial data or the requirements of the protocol being used
demand otherwise.
Next Byte Delay
The amount of time the bus must be idle after the Minimum Packet Size has
expired before the radio sends everything in it’s serial buffer. Values of 00 to
10 may be chosen, with a default of 00. Each unit of time is the reciprocal of
the Baud Rate (e.g. 104 µs at 9600 Baud).
Minimum Packet Size
Expected packet size bytes. Values of 01 to 99 may be chosen, with a default
of 01. Packets smaller than this will wait to see if additional packets arrive
during this time window. If additional packets arrive, they will be combined
into a single transmission.
Maximum Packet Size
Maximum number of bytes per transmission. Values from one more than
the Minimum Packet Size to 768 may be chosen with a default of 024 bytes.
Packets larger than this size will be sent over the RF as fragments and reassembled at the receiver radio.
7. Additional information about the tuning parameters. The data protocol you
are using may require certain groupings of the bytes or particular timing of the
• If you want minimum latency so that data is received as soon as possible after
it is sent, select a Next Byte Delay of 00 and a Minimum Packet Size of 01.
• If you are sending large blocks of data, a Minimum Packet Size of 01 can cause
the AW900R2’s buffer to overflow and bytes will be lost. The value can be increased to a maximum that depends on the Baud Rate, corresponding to about
5.3 milliseconds:
Baud Rate
Largest Minimum Packet Size
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• Dumping a large volume of data at a fixed high Baud rate runs the risk of data
corruption if anything (tuning, noise retries, channel switching, etc.) causes
the 4 KB buffer in the sending radio to be overwritten.
8. The AW900R2’s chosen configuration can be saved to a local data file for future
use by clicking the “Save” button. You might want to do this when configuring both
ends of the link since the AccessPoint/Subscriber Unit choice is the only difference.
The configuration can then be retrieved using the “Load” button. In each case, a file
explorer popup allows you to save and retrieve the config file to a location of your
choice. The default filename is EVK.conf.
9. When you are ready to upload the configuration to the AW900R2 module, click
the “Send” button. This uploads the configuration and causes the module to reboot.
You can reboot without upload by clicking “Reboot Target.” Keep straight which
COM port belongs to which USB interface. It is common to connect the two modules
of a link at the same time to two different USB ports and if you get confused about
which port is which, the wrong configuration can be overwritten.
10. After both modules of the link are configured and rebooted, they should successfully find each other and link. The successful accomplishment of this linkage
can be determined either by the Stats & Spectrum tab in EvkUtilityLite or by seeing
the correct pattern of LEDs on the modules.
11. Click the Stats & Spectrum tab at the top of the EvkUtilityLite window. Make
sure that you select the right COM port with the dropdown menu at the top. (It
will not change automatically to match the port selected on the Boot Configuration
tab.) This page will appear:
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12. A snapshot of the module’s status can be retrieved by clicking the “Get Stats”
button. Here is an explanation of the values returned:
Received Signal Strength Indication in dBm. This is useful when aligning
antennas or evaluating path attenuation.
Radio Block Error Rate
Percentage of radio data blocks that are incorrectly received.
Radio Failed Packets
Count of failed data packets since the last reboot. This may remain zero
because of retries even when the Radio Block Error Rate climbs because of
a poor connection.
Radio Passed Packets
Count of successful data packets since the last reboot.
Radio Total Packets
Total packets transmitted since last reboot.
Radio Average TX Size
Average bytes transmitted per packet, a function of the serial data source
and the selected tuning parameters.
Radio Average RX Size
Average bytes received per packet, a function of the serial data source and
the selected tuning parameters.
Current RF Channel
The RF channel currently in use. If a fixed channel is configured, this
number should match. If automatic selection, this number may change
from time to time as the radios look for the channel with the lowest block
error rate.
Connected Subscribers/
Subscriber Key
This number should always be 1 for the AW900R2.
RF Connected
True if the two radios are linked and able to exchange data. False otherwise.
Radio Active
True if the radio has a valid configuration and is linked or searching for a
link. False otherwise.
Radio Version
900 MHz Full Band for this product.
Radio Firmware Release
The version of the firmware running in this module. Check www.avalanwireless.com from time to time to see if a later version is available.
13. The Spectrum Scan may be used to identify interference issues. When “Get
Spectrum Scan” is clicked, the module’s transmitter is disabled, interrupting the
serial data flow. The receiver is tuned across the 900 MHz band and the RSSI is plotted for each frequency. You can select the frequency step size and the number of
samples to be taken and averaged at each frequency. The smaller the step size and
the larger the number of samples averaged, the longer the scan will take. If you
perform a scan from the Subscriber Unit, you will see large transient spikes caused
by the Access Point scanning the channels because the Subscriber Unit has gone off
line. Scanning from the Access Point will show a better picture of external interference sources. After a spectrum scan, the radio will resume normal operation.
14. The LEDs on the AW900R2 PC board can be very useful in determining whether
the link is operating normally or if not, where the trouble might be. The next page
shows where these LEDs are located and the meaning of each.
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Reset Switch:
Press momentarily to
cycle power and reboot
the module.
DIP Switches
(only used
during factory testing)
Shows link quality (more
lit the better) or indicates
“key exchange mode” if
blinking sequentially
Blinks when module is receiving RS-232 data
Blinks when module is transmitting RS-232 data
Blinks when module is receiving RF data
Blinks when module is transmitting RF data
By adding the numbers that are lit, you can determine the current radio channel. Valid channels are 1 to 12, CH16 and CH32
are not used. For the frequency of each channel, see the table
on page 5.
Excellent link quality: no retransmissions
Very good link quality: few retransmissions
Good link quality: occasional retransmissions
Fair link quality: some retransmissions
Poor link quality: frequent retransmissions
No link quality: no link available
Lit when the module has DC power
Located between the USB and power connectors, these LEDs
indicate activity through the USB port.
If LEDs CH1 to CH8 are cycling in a binary count and only the bottom link quality
LED is lit, the radio is active and searching for another module to link to. When link
is accomplished, the Channel LEDs will stop, showing the RF channel selected and
the link quality LEDs will show the signal strength.
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AW900R2-EVAL User’s Manual
Example Test Method
If you already have a suitable RS-232 data source and an equally suitable destination, you will probably want to evaluate the AW900R2 capability with those. If you
do not, you might consider using USB to Serial converters and hyperterm or some
other terminal emulator program.
Here is a block diagram of a possible evaluation test setup:
USB Configuration & Status
USB Data
USB to RS-232
RS-232 Data
RF Data
USB Configuration & Status
USB Data
USB to RS-232
RS-232 Data
Notes about this test setup:
1.One PC could be used rather than two, but you then need 4 available high
power USB 2.0 ports and it is difficult to physically separate the radio antennas
2.The PCs need to be running Windows XP or later.
3.There are a number of inexpensive USB to RS-232 converters on the market.
We used a pair of GC-ATC-810 USB-High Speed Serial Converters available from
Grid Connect (www.gridconnect.com). These converters have a driver CD included and have a 9-pin DB9 connector plus a screw terminal breakout adapter.
Pin 2 is RXD and should be connected to the TX terminal on the AW900R2. Pin 3
is TXD and should be connected to the RX terminal. Pin 5 is ground and should
be connected to the GND terminal on the AW900R2.
4.You will need to install Virtual COM Port drivers for both the USB to RS-232
converters and for the configuration and status port on the AW900R2. In device
manager on your PC, you will see COM ports for both the serial converter and
the AW900R2. Connect these one at a time and note the assigned port numbers
to keep them straight.
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5.You will need to install EvkUtilityLite.exe and zedgraph.dll on the PC. If you
attempt to select the serial converter’s COM port with the utility, you will get
a “port closed” error, but no harm will be done.
6.You will need a serial data source program installed on your PC. If you are running Windows XP, hyperterm is already there and makes a good data source.
Unfortunately, Microsoft has discontinued inclusion of hyperterm and you will
need another alternative for later versions of Windows. There are many available for free or at low cost and they may be found by Internet search. The one
we used in our setup was Tera Term, a free terminal emulator whose latest version can be downloaded from sourceforge: ttssh2.sourceforge.jp. The terminal
emulator program should be configured to connect to the Virtual COM port of
the Serial Converter and its serial port properties like Baud rate, data bits, etc.
should match the configuration settings in the AW900R2s. It is also useful to set
local echo and CR-LF end-of-line for transmit and receive.
7.When everything is connected properly and all the software pieces are in
place, you should be able to type characters into the terminal emulator on
one PC and see them appear in the terminal emulator window on the other PC.
Tera Term also supports text file transfers if you want to send more data than
what you are willing to type or wish to explore the effect of the radio’s tuning
parameters on the data stream.
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Technical specifications
Serial Baud Rate
9600, 19200, 38400, 57600, 76800, 115200
RS-232 Signal Characteristics
See data sheet for Maxim 3221 chip (www.maxim-ic.com)
RF transmission rate
1.536 Mbps
RF Output Power
+21 dBm (4 Watts EIRP with 15 dBi antenna)
Receiver Sensitivity
-97 dBm at 10-4 Bit Error Rate
Radio Link Budget
148 dB with 15 dBi antennas
Up to 40 miles line-of-sight with 15 dBi antennas
RF channels/bandwidth
12 non-overlapping with 2.0833 MHz spacing and 1.75 MHz
Channel selection
Automatic or manual via USB interface
Adjacent band rejection
SAW receiver filter attenuates cellular and pager interference
Error correction
Sub-block error detection and retransmission
128-bit AES, meets FIPS 197 Standard
Evk Utility Management Tools
Serial port configuration, encryption keys, tuning parameters, QoS statistics, spectrum analyzer
Status LEDs
power, RF activity, serial data activity, channel, link quality
RF: RPSMA Female, RS-232, power: Phoenix screw terminals
Power consumption
Transmit: 0.54 Watts, Receive: 0.45 Watts
5-45 VDC
Power regulation
Switching regulator
Transmit current draw
175 ma at 9 VDC
140 ma at 12 VDC
35 ma at 48 VDC
Operating Temperature Range
-40 ºC to +80 ºC
99 by 66 by 23 mm, 46 grams, connectors included
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AW900R2-EVAL User’s Manual
FCC Certification
The AW900R2 OEM RF Module complies with Part 15 of the FCC rules and regulations.
Compliance with labeling requirements, FCC notices and antenna regulations is required.
IMPORTANT: The AW900R2 OEM RF Modules have been certified by the FCC for use with
other products without any further certification (as per FCC section 2.1091). Changes or
modifications not expressly approved by AvaLAN could void the user’s authority to operate
the equipment.
IMPORTANT: OEMs must test their final product to comply with unintentional radiators
(FCC section 15.107 and 15.109) before declaring compliance of their final product to Part 15
of the FCC Rules.
IMPORTANT: The AW900R2 OEM RF Modules have been certified for fixed base station
and mobile applications. If modules will be used for portable applications, the device must
undergo SAR testing.
Labeling Requirements
In order to inherit AvaLAN’s FCC Certification, compliance requires that the following be
stated on the device:
Contains FCC ID: R4N-AW900MR
The enclosed device complies with Part 15 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.
The Original Equipment Manufacturer (OEM) must ensure that FCC labeling requirements are
met. This includes a clearly visible label on the outside of the final product enclosure that
displays the contents shown in the box above.
User’s Manual Requirements
In order to inherit AvaLAN’s FCC Certification, compliance requires that the following be
stated in the user’s manual:
Compliance Statement ( Part 15.19 )
This device complies with Part 15 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.
Warning ( Part 15.21 )
Changes or modifications not expressly approved by the party responsible for compliance could void the user’s
authority to operate the equipment.
RF Exposure ( OET Bulletin 65 )
To comply with FCC RF exposure requirements for mobile transmitting devices, this transmitter should only be used
or installed at locations where there is at least 20cm separation distance between the antenna and all persons.
Information to the User - Part 15.105 (b)
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, may cause harmful interference to radio communications. However, there
is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment off and on, the
user is encouraged to try to correct the interference by one or more of the following measures:
--Reorient or relocate the receiving antenna.
--Increase the separation between the equipment and receiver.
--Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
--Consult the dealer or an experienced radio/TV technician for help.
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