AvaLAN Wireless AW900R2 User Manual

AvaLAN

W I R E L E S S

AW900R2-EVAL

USER’S MANUAL

900 MHz Wireless RS-232 Module

Evaluation Kit

Industrial-grade, long-range wireless systems

AW900R2-EVAL

Thank you for your purchase of the AW900R2-EVAL Wireless RS-232 Module Evaluation
Kit.

If you have any questions when conguring your AvaLAN system, the best place to
get answers is to visit www.avalanwireless.com. You will also nd the latest updates
there.

If more assistance is needed, send email to [e-mail].

To speak to a live technician, please call technical support at the number below
during normal business hours.

User’s Manual

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 modication of the product.

© 2010 by AvaLAN Wireless Systems Inc. All rights reserved.

Revision 06.28.2010

125A Castle Drive

Madison, AL 35758

Sales: [phone]

Technical Support: [phone]

Customer Service: [phone]

Fax: [phone]

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PAGE 2

User’s Manual AW900R2-EVAL

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 congured 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 congured, a pair of
AW900R2 modules behave just like an RS-232 cable but without the length con­straint and without a physical wire.

Conguring a wireless link with the AW900R2 requires the establishment of six
elements:

• One radio must be congured as the Access Point (AP) and the other one must
be congured as the Subscriber Unit (SU).

• Both radios must share a common Network Name, a 32-bit identier.

• 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 congured 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

Status LEDs

USB

900 MHz
Antenna

Plain black wire

White-striped wire

Reset Switch

(cycles power)

RS-232

Data

Source

Transmit

Receive

Ground

Note:

The USB connection is not needed after the link is
congured 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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User’s Manual AW900R2-EVAL

Physical Dimensions

66 mm

23 mm

58 mm

18 mm

55 mm

63 mm

15 mm

25 mm

33 mm

18 mm

900 MHz Channels

Channel Center Frequency

0 Auto Mode
1 903.12500 MHz
2 905.20833 MHz
3 907.29167 MHz
4 909.37500 MHz
5 911.45833 MHz
6 913.54167 MHz
7 915.62500 MHz
8 917.70833 MHz

9 919.79167 MHz
10 921.87500 MHz
11 923.95833 MHz
12 926.04167 MHz

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AW900R2-EVAL

User’s Manual

Conguration

Setting or changing the conguration (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
le 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 le 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 open Windows 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 rst step when up and
running should be to open Device Manager to determine the correct port number.

3. Next, you will need a conguration utility and its associated dll le from AvaLAN.
Go to our website, http://www.avalanwireless.com. Navigate to “Support” then
“Downloads.” Choose the “AvaLAN Evk Utility Lite” le and download the zip le.
This zip archive contains two les, 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 rst to be sure the dll le is there.

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User’s Manual AW900R2-EVAL

4. Run EvkUtilityLite.exe and you should see a window like this:

5. Use the dropdown menu labeled “Boot Cong Serial Port” to select the virtual
COM port connected to your AW900R2 module. Note that the list is populated only
when EvkUtilityLite rst 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 conguration from the module.

6. If you are satised with the module’s conguration and status, stop here. If
changes are needed, here is an explanation of the parameters that may be set on
the Boot Conguration page:

Radio Conguration Meaning

AccessPoint/Subscriber
Unit

Number of Subscriber
Units/Subscriber ID

Channel 00-12 The RF channel for the module. The frequencies corresponding to each chan-

Network Name A 32-bit value (8 Hex digits, 0 to 9 and A to F) that must be the same for the

AES Private Key A 128-bit value (32 Hex digits) that must be the same for the two radio mod-

Technical support [phone] www.avalanwireless.com

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.

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
versions.)

nel are shown in the table on page 5. Choose “00” for automatic channel
selection or set “01” to “12” for a xed choice.

two radio modules of the link. If you have multiple links operating in the
same vicinity, give each link a unique value.

ules in the link. This key is used to encrypt the transmitted data and decrypt
the received data.

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AW900R2-EVAL

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 Bits Selectable 7 or 8 data bits (8 is the most common choice)

Parity Selectable among “none”, “even”, “odd”, “mark” or “space” (“none” is the

Stop Bits Select 1 or 2 stop bits (2 is the most common choice)

Tuning Parameters These affect the behavior of the RF packet transmissions relative to the

Next Byte Delay The amount of time the bus must be idle after the Minimum Packet Size has

Minimum Packet Size Expected packet size bytes. Values of 01 to 99 may be chosen, with a default

Maximum Packet Size Maximum number of bytes per transmission. Values from one more than

User’s Manual

data rate).

most common choice)

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.

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).

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.

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. Here is additional information about the tuning parameters. The data protocol
you are using may require certain groupings of the bytes or particular timing of the
information:

• 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 overow 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

9600 5

19200 10

38400 20

57600 30

76800 40

115200 60

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User’s Manual AW900R2-EVAL

• Dumping a large volume of data at a xed 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 conguration can be saved to a local data le for future
use by clicking the “Save” button. You might want to do this when conguring both
ends of the link since the AccessPoint/Subscriber Unit choice is the only difference.
The conguration can then be retrieved using the “Load” button. In each case, a le
explorer popup allows you to save and retrieve the cong le to a location of your
choice. The default lename is EVK.conf.

9. When you are ready to upload the conguration to the AW900R2 module, click
the “Send” button. This uploads the conguration 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 conguration can be overwritten.

10. After both modules of the link are congured and rebooted, they should suc­cessfully nd 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 Conguration
tab.) This page will appear:

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AW900R2-EVAL

User’s Manual

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:

Name Meaning

RSSI Received Signal Strength Indication in dBm. This is useful when aligning

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

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

Radio Average RX Size Average bytes received per packet, a function of the serial data source and

Current RF Channel The RF channel currently in use. If a xed channel is congured, this

Connected Subscribers/
Subscriber Key

RF Connected True if the two radios are linked and able to exchange data. False other-

Radio Active True if the radio has a valid conguration and is linked or searching for a

Radio Version 900 MHz Full Band for this product.

Radio Firmware Release The version of the rmware running in this module. Check www.avalan-

antennas or evaluating path attenuation.

because of retries even when the Radio Block Error Rate climbs because of
a poor connection.

and the selected tuning parameters.

the selected tuning parameters.

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.

This number should always be 1 for the AW900R2.

wise.

link. False otherwise.

wireless.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 ow. 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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User’s Manual AW900R2-EVAL

Reset Switch:

Press momentarily to
cycle power and reboot
the module.

DIP Switches

(only used
during factory testing)

LEDs

LED Function Color

SER RX Blinks when module is receiving RS-232 data Green
SER TX Blinks when module is transmitting RS-232 data Green
RF RX Blinks when module is receiving RF data Green
RF TX Blinks when module is transmitting RF data Green
CH1 By adding the numbers that are lit, you can determine the cur­CH2
CH4
CH8
CH16
CH32
Shows link quality (more

lit the better) or indicates
“key exchange mode” if
blinking sequentially

PWR Lit when the module has DC power Red
USB RX Located between the USB and power connectors, these LEDs
USB TX Amber

rent 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 Green
Very good link quality: few retransmissions Green
Good link quality: occasional retransmissions Amber
Fair link quality: some retransmissions Amber
Poor link quality: frequent retransmissions Red
No link quality: no link available Red

indicate activity through the USB port.

Green

Amber

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 Conguration & Status

PC

PC

USB to RS-232

USB Data

USB Data

Converter

USB Conguration & Status

USB to RS-232

Converter

RS-232 Data

RS-232 Data

AW900R2

RF Data

AW900R2

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 difcult to physically separate the radio antennas
sufciently.

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 conguration 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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User’s Manual AW900R2-EVAL

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 congured 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 conguration 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 le 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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User’s Manual

Notes

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User’s Manual AW900R2-EVAL

Technical specications

Characteristic Specication/Description

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

Range 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 lter attenuates cellular and pager interfer-

Error correction Sub-block error detection and retransmission

Encryption 128-bit AES, meets FIPS 197 Standard

Evk Utility Management Tools Serial port conguration, encryption keys, tuning param-

Status LEDs power, RF activity, serial data activity, channel, link qual-

Connectors RF: RPSMA Female, RS-232, power: Phoenix screw termi-

Power consumption Transmit: 0.54 Watts, Receive: 0.45 Watts

Voltage 5-45 VDC

Power regulation Switching regulator

Transmit current draw 175 ma at 9 VDC

Operating Temperature Range -40 ºC to +80 ºC

Size 99 by 66 by 23 mm, 46 grams, connectors included

bandwidth

ence

eters, QoS statistics, spectrum analyzer

ity

nals

140 ma at 12 VDC
35 ma at 48 VDC

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PAGE 15

AW900R2-EVAL

User’s Manual

FCC Certication

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 certied by the FCC for use with
other products without any further certication (as per FCC section 2.1091). Changes or
modications not expressly approved by AvaLAN could void the user’s authority to operate
the equipment.
IMPORTANT: OEMs must test their nal product to comply with unintentional radiators
(FCC section 15.107 and 15.109) before declaring compliance of their nal product to Part 15
of the FCC Rules.
IMPORTANT: The AW900R2 OEM RF Modules have been certied for xed 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 Certication, 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 nal product enclosure that
displays the contents shown in the box above.

User’s Manual Requirements

In order to inherit AvaLAN’s FCC Certication, 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 modications 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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PAGE 16