FreeWave LRS400S User manual

LRS400S Data Transceiver Manual
LUM0025AA Rev A Version 1.0 i
FreeWave Technologies
LRS400S
Data Transceiver
Version 1.0
FreeWave Technologies, Inc.
1880 South Flatiron Court
Boulder, CO 80301
[phone]
[phone] Fax
www.FreeWave.com

LRS400S Data Transceiver Users Manual
LUM0025AA Rev A Version 1.0 ii
LICENSED BAND WIRELESS DATA TRANSCEIVER USER MANUAL
Copyright © 1995-2010 by FreeWave Technologies, Inc. All rights reserved. Published 2010.
WARRANTY
FreeWave Technologies warrants your FreeWave® Wireless Data Transceiver against defects in
materials and manufacturing for a period of two years from the date of shipment. In the event of a
Product failure due to materials or workmanship, FreeWave will, at its option, repair or replace the
Product. The Product must be returned to FreeWave upon receiving a Return Material Authorization
(RMA) for evaluation of Warranty Coverage.
In no event will FreeWave Technologies Inc., its suppliers, and its licensors be liable for any damages
arising from the use of or inability to use this Product. This includes business interruption, loss of
business information, or other loss which may arise from the use of this Product. Please be advised that
OEM customer’s warranty periods may vary.
Warranty Policy may not apply:
1. If Product repair, adjustments or parts replacements is required due to accident, neglect, unusual
physical, electrical or electromagnetic stress.
2. If Product is used outside of FreeWave specifications.
3. If Product has been modified, repaired or altered by Customer unless FreeWave specifically
authorized such alterations in each instance in writing. This includes the addition of conformal
coating.
Special Rate Replacement Option
A special rate replacement option is offered to non-warranty returns or upgrades. The option to purchase
the replacement unit at this special rate is only valid for that RMA. The special replacement rate option
expires if not exercised within 30 days of final disposition of RMA.
RESTRICTED RIGHTS
Any product names mentioned in this manual may be trademarks, or registered trademarks of their
respective companies and are hereby acknowledged.
Information in this manual is subject to change without notice and is proprietary and confidential to
FreeWave Technologies, Inc.
This manual is for use by purchasers and other authorized users of the FreeWave® Wireless Data
Transceiver only.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic or
mechanical, or for any purpose without the express written permission of FreeWave Technologies, Inc.
FreeWave’s Wireless Data Transceivers are designed and manufactured in the United States of America.
Printed in the United States of America.

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CAUTION: The LRS400S series transceiver have maximum transmitted output power of 2W. It is
recommended that the transmit antenna be kept at least 71 cm away from nearby persons to satisfy FCC
RF exposure requirements.

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Table of Contents
ABOUT FREEWAVE TRANSCEIVERS.................................................................................................................6
CHOOSING A LOCATION FOR THE TRANSCEIVERS....................................................................................6
CHOOSING POINT-TO-POINT OR POINT-TO-MULTIPOINT OPERATION ........................................................................7
QUICK START ON A POINT-TO-MULTIPOINT NETWORK ..........................................................................8
POINT-TO-MULTIPOINT OPERATION LEDS................................................................................................................8
QUICK START ON A POINT-TO-POINT NETWORK........................................................................................9
POINT-TO-POINT OPERATION LEDS...........................................................................................................................9
SETTING UP A TRANSCEIVER...........................................................................................................................10
OPERATION MODE....................................................................................................................................................10
BAUD RATE..............................................................................................................................................................12
CALL BOOK..............................................................................................................................................................15
RADIO TRANSMISSION CHARACTERISTICS ...............................................................................................................16
EDIT RADIO TRANSMISSION CHARACTERISTICS.......................................................................................................16
Setting Xmit and Rcv Frequencies.......................................................................................................................16
(1) and (2) Max Packet Size and Min Packet Size...............................................................................................17
(3) Xmit Rate........................................................................................................................................................18
(4) RF Data Rate .................................................................................................................................................18
(5)RF Xmit Power................................................................................................................................................18
(6) Slave Security.................................................................................................................................................19
(7) RTS to CTS.....................................................................................................................................................19
(8) Retry Time Out...............................................................................................................................................19
(9) Lowpower Mode.............................................................................................................................................20
(C) Remote LED ..................................................................................................................................................21
MULTIPOINT PARAMETERS ......................................................................................................................................22
EDIT MULTIPOINT PARAMETERS..............................................................................................................................22
(0) Repeaters........................................................................................................................................................22
(1) Master Packet Repeat ....................................................................................................................................22
(2) Max Slave Retry.............................................................................................................................................23
(3) Retry Odds .....................................................................................................................................................23
(4) DTR Connect..................................................................................................................................................23
(6) Network ID.....................................................................................................................................................23
(8) MultiMaster Sync...........................................................................................................................................23
(9) 1 PPS Enable/Delay.......................................................................................................................................23
(A) Slave/Repeater...............................................................................................................................................24
(B) Diagnostics....................................................................................................................................................24
(C) Subnet ID.......................................................................................................................................................24
(D) Radio ID........................................................................................................................................................25
(E) Local Access..................................................................................................................................................25
(G) Radio Name...................................................................................................................................................25
RADIO INFORMATION ...............................................................................................................................................26
Number of Disconnects........................................................................................................................................26
Antenna Reflected Power.....................................................................................................................................26
Average Noise Level............................................................................................................................................26
Average Signal Level...........................................................................................................................................27
Overall Rcv Rate (%)...........................................................................................................................................27
Radio Temperature..............................................................................................................................................27
FACTORY DEFAULT SETTINGS.........................................................................................................................28
OPERATIONAL RS-422 AND RS-485 INFORMATION .................................................................................................29
RS-422 and RS-485 Full Duplex Pin-Outs..........................................................................................................30

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RS-485 Half Duplex Pin-Outs..............................................................................................................................30
RS232 PIN ASSIGNMENTS ........................................................................................................................................30
RF BOARD PINOUT...................................................................................................................................................31
FREEWAVE TECHNICAL SUPPORT ............................................................................................................................31

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About FreeWave Transceivers
FreeWave transceivers operate in virtually any environment where RS232 data communications occur. A
pair of transceivers function as a 9-pin null modem cable. If the FreeWave transceivers are to be used in
an application where a null modem cable is used, such as communication between two computers, then
the FreeWave transceivers can be connected directly. If FreeWave transceivers are to be used to replace
a straight-through RS232 cable, then a null modem cable must be placed between the transceiver and
the DTE instrument to which it is connected.
Choosing a Location for the Transceivers
Placement of the FreeWave transceiver is likely to have a significant impact on its performance. The key
to the overall robustness of the radio link is the height of the antenna. In general, FreeWave units with a
higher antenna placement will have a better communication link. In practice, the transceiver should be
placed away from computers, telephones, answering machines and other similar equipment. The RS232
cable included with the transceiver usually provides ample distance for placement away from other
equipment. To improve the data link, FreeWave Technologies offers directional antennas with cable
lengths ranging from 3 to 200 feet. When using an external antenna, placement of that antenna is critical
to a solid data link. Other antennas in close proximity are a potential source of interference; use the Radio
Statistics to help identify potential problems. The Show Radio Statistics page is found in option 4 in the
Main Menu. An adjustment as little as 2 feet in antenna placement can resolve some noise problems. In
extreme cases, band pass filter may reduce the out-of-band noise.

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Choosing Point-to-Point or Point-to-MultiPoint Operation
A Point-to-Point network is limited to one Master and one Slave transceiver.
In a Point-to-MultiPoint network (also referred to as MultiPoint network) the transceiver, designated as a
Master, is able to simultaneously communicate with numerous Slaves. In its simplest form, a MultiPoint
network functions with the Master broadcasting its messages to all Slaves and the Slaves responding to
the Master when given data by the device connected to the data port.
It is important to note the differences between Point-to-Point and MultiPoint networks. In a Point-to-Point
network all packets are acknowledged, whether sent from the Master to the Slave or from the Slave to the
Master. In a MultiPoint network, outbound packets from the Master to Slaves are sent a set number of
times determined by the user. The receiving transceiver will accept the first packet received that passes
the 32 bit CRC. However, the packet is not acknowledged. On the return trip to the Master, all packets
sent by the Slave are acknowledged or retransmitted until they are acknowledged. Therefore, the return
link in a MultiPoint network is generally very robust.
Note: In licensed band operation it is suggested to set the repeated master packets at 0 due to
the spectrum being quiet. This will maximize throughput and leverage the advantages of licensed
band operation.
Traditionally, a MultiPoint network is used in applications where data is collected from many instruments
and reported back to one central site. As such, the architecture of such a network is different from Point-
to-Point applications. The number of radios in a MultiPoint network is influenced by the following
parameters:
1. Size of the blocks of data. The longer the data blocks, the smaller the network capacity.
2. Baud rate.
3. The amount of contention between Slaves. Polled Slaves vs. timed Slaves.
For example, if the network will be polling Slaves once a day to retrieve sparse data, several hundred
Slaves could be configured to a single Master. However, if each Slave will be transmitting data at greater
levels, then fewer Slaves should be linked to the Master. The overall network will be closer to capacity
with fewer Slaves.
For examples and additional information on data communication links, see the section Examples
of Data Communication Links later in this document.

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Quick Start on a Point-to-MultiPoint Network
The following is a quick start guide for setting up two transceivers in Point-to-MultiPoint mode. This mode allows for a
Master to communicate with several Slaves simultaneously.
1. Connect the transceiver to the serial port of a computer either through a serial cable or via the diagnostics
cable. Make sure to connect the radio to a power source (typically, 6 to 30 VDC).
2. Open up a HyperTerminal session.
•Use the following settings in connecting with HyperTerminal
•Connect to COMx (where 'x' is the number of the com port being connected to)
•Set data rate to - 19,200, data bits - 8, Parity- none, Stop bits – 1, Flow control – none.
3. Press the Setup button on the radio. If using the diagnostics cable, press Shift-U (capital U).
•The three lights on the board should all turn green, indicating Setup mode.
•The main menu will appear on the screen.
4. Press 0to get into the Operation Mode menu.
•Press 2to set the radio as a point to MultiPoint Master.
•OR, Press 3 to set the radio as a point to MultiPoint Slave.
•Press Esc to get back to Main menu.
5. Press 1in the main menu to change the Baud Rate.
•The baud rate must be changed to match the baud rate of the device that the radio is to be attached to.
•Press Esc to get back to Main menu.
6. At the Main Menu, press 3.
•Set FreqKey, Max Packet Size, Min Packet Size, RF Data rate identical on all radios in the network.
Note: Changing these values may help to eliminate interference from other FreeWave networks.
•Press Esc to get back to Main menu.
7. At the Main Menu, press 5.
•Set the Network ID value to any value between 1 and 4095, except 255.
•Make sure this value is the same on every radio in the network.
Point-to-MultiPoint Operation LEDs.
Master Slave
Condition Carrier Detect
(CD) Transmit (TX) Clear to Send (CTS) Carrier Detect
(CD)
Transmit
(TX) Clear to Send
(CTS)
Powered, not linked Solid red
brightSolid red dimOff Solid red brightOff Blinking red
Slave linked to Master,
no data Solid red brightSolid red dimOff Solid greenOff * Solid red bright
Slave linked to Master,
Master sending data to
Slave
Solid red
brightSolid red dimOff Solid greenOff * Solid red bright
Slave linked to Master,
Slave sending data to
Master
Solid green
RCV data
or Solid red
bright
Solid red
dimIntermittent flash
redÑoÒ
Solid
greenIntermittent flash
redÑoÒ
* Solid red
bright
Master with diagnostics
program running Solid red
brightSolid red
dimIntermittent flash
redÑoÒ
Solid
greenIntermittent flash
redÑoÒ
* Solid red
bright
* Clear to Send LED will be solid redwith a solid link, as the link weakens the Clear to Send LED light on the Slave
will begin to flash\.

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Quick Start on a Point-to-Point Network
When purchased as a pair, the FreeWave® Wireless Data Transceivers are shipped from the factory pre-
configured to operate in Point-to-Point applications. To establish communications between a pair of
FreeWave Wireless Data Transceivers just received from the factory:
1. Connect antennas to the transceivers. Freewave Technologies recommends that the antenna
port be loaded at all times to prevent damage to the LRS400S radios. Noise potential may be
reduced on the bench by lowering the Xmit power.
2. Connect the transceiver to the instrument with the RS232 cable and also attach power. The
cable supplied with enclosed transceivers (except Waterproof) is a 9-pin male serial; professional
board level transceivers will need a separate programming cable (sold separately).
3. Set the Modem mode in each transceiver. One should be set as a Point-to-Point Master (Mode
0) and the other set as a Point-to-Point Slave (Mode 1).
4. Set the baud rate on each transceiver to match the baud rate of the instrument to which it is
attached. Please note, when setting the transceiver's baud rate, its RS232 data rate is set. The
baud rate does not have to be on the same setting for the two transceivers.
5. Edit the Call Book. Enter the Slave serial number in the Master’s Call Book. Enter the Master’s
Serial number in the Slave’s Call Book, or disable Slave Security (in the Slave).
6. Shortly after both transceivers are plugged in, they should establish a communications link with
each other and the connection is complete. Using the table below, verify that the radios are
operating as expected.
Point-to-Point Operation LEDs
Master Slave
Condition Carrier
Detect
(CD)
Transmit
(TX) Clear to Send (CTS) Carrier Detect (CD) Transmit (TX) Clear to Send (CTS)
Powered, no link Solid red
bright Solid red brightSolid red brightSolid red
brightOff Blinking red
\
Linked, sending
sparse data Solid greenIntermittent flash
redÑoÒ
Intermittent
flash
redÑoÒ
Solid
greenIntermittent flash
redÑoÒ
Intermittent
flash
redÑoÒ
Master calling
Slave Solid red brightSolid red dimSolid red brightSolid red brightOff Blinking red
\
Mode 6 - waiting
for ATD command Solid red brightOff Blinking red\Solid red brightOff Blinking red
\
Setup Mode Solid
greenSolid greenSolid greenSolid greenSolid greenSolid green

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Setting up a Transceiver
Operation Mode
The Operation Mode option designates the method FreeWave transceivers use to communicate with
each other. FreeWave transceivers operate in a Master to Slave configuration. Before the transceivers
can operate together, they must be set up to properly communicate.
In a Point-to-Point configuration, Master or Slave Mode may be used on either end of the communication
link without performance degradation. When setting up the transceiver, remember that a number of
parameters are controlled by the settings in the Master. Therefore, deploying the Master on the
communications end where it will be easier to access is advised, but not necessary.
Operation
Mode Description
Point-to-Point
Master (0) This mode designates the transceiver as the Master in Point-to-Point mode. The Master may call any or all Slaves designated in its Call Book.
In Point-to-Point mode the Master determines the setting used for most of the
radio transmission characteristics, regardless of the settings in the Slave. The
settings not determined by the Master are: RF Xmit Power, Slave Security, Retry
Time Out, and the Hop Table settings.
A quick method of identifying a Master is to power the transceiver. Prior to
establishing a communication link with a Slave, all three of the Master’s LEDs
will be solid red.
Point-to-Point
Slave (1) This mode designates the transceiver as a Slave in Point-to-Point mode. The Slave communicates with any Master in its Call Book.
When functioning as a Slave, the Entry to Call feature in the transceiver’s Call
Book is not operational. The Call Book may be bypassed in the Slave by setting
Slave Security to 1. See the Slave Security section later in this manual.
Point–to-
MultiPoint
Master (2)
This mode designates the transceiver as a Master in MultiPoint mode. This
mode allows one Master transceiver to simultaneously be in communication with
numerous Slaves.
A Point-to-MultiPoint Master communicates only with other transceivers
designated as Point-to-MultiPoint Slaves.
Point-to-
MultiPoint This mode designates the transceiver as a Slave in MultiPoint mode. This mode allows the Slave to communicate with a MultiPoint Master. The Slave may

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Slave (3) communicate with its Master.
Point-to-Point
Repeater (5) FreeWave allows the use of one repeater in a Point-to-Point communications link, significantly extending the operating range. When designated as a
Repeater, a transceiver behaves as a pass-through link. All settings for the call
book, baud rates and radio transmission characteristics are disabled. A Repeater
will connect with any Master that calls it. The Repeater must be set up properly
in the Master's call book.
Point-to-Point
Slave/Master
Switchable (6)
Mode 6 allows the transceiver to be controlled entirely through software
commands. A number of key parameters in FreeWave's user interface may be
changed either directly with a program such as Windows Terminal or through the
use of script files. Additionally, when the Point-to-Point Slave/Master Switchable
option is selected and the transceiver is not calling a Slave, it will function as a
Slave and accept any appropriate calls from other transceivers.
Point-to-
MultiPoint
Repeater (7)
This option allows the transceiver to operate as a Repeater in a MultiPoint
network. See the MultiPoint parameters section for details on enabling
MultiPoint Slave/Repeater mode.
Note: The use of repeaters in Point to Multipoint Networks is restricted to one
repeater per network.

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Baud Rate
This setting is the communication rate between the transceiver and the instrument to which it is
connected. It is important to note that this is independent of the baud rate for the other transceiver(s) in
the network. For example, a pair of transceivers may be used in an application to send data from remote
process instrumentation to an engineer's computer. In this application, the baud rate for the transceiver
on the instrumentation might be set to 9600, and the transceiver on the engineer’s computer might be set
to 57,600.
Set Baud Rate
1. Select the appropriate baud rate to match the attached device.

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Baud Rate Description
Actual Baud Rate
(selections 0-9) The actual baud rate for the transceiver’s data port.
It is desirable to set the baud rate to the highest level supported by the device to
which it is connected. In certain circumstances, however, this may actually result
in slower data communications.
Data, Parity There are six data word length and parity configurations available to be used with
FreeWave transceivers. The default setting is 0 (8, N, 1) and is the most commonly
used serial communications protocol. Select the appropriate option to
communicate with the end device.
Data Bits Parity Stop Bits
8 None 1
7 Even 1
7 Odd 1
8 None 2
8 Even 1
8 Odd 1
Modbus RTU Support for Modbus RTU protocol is available. The default setting for Modbus
RTU is 0 (Not Enabled).
To enable Modbus capability, set Modbus RTU to 1.
Note: When using the transceiver in Modbus RTU mode, the Master Packet
Repeat must be set the same in all radios whether the network is in Point-to-Point o
r
MultiPoint mode. The Modbus RTU mode must be selected when transceivers are
configured in RS485 or RS422 mode.
Serial Interface In products for which the protocol of the data port is software selectable, use this
menu to set the protocol of the data port. In the TTL RF board product this setting
must be "0".
Protocol Additional Information
RS232 Also used for TTL transceivers.
RS422 Modbus RTU mode must be enabled. See above.
RS485 Modbus RTU mode must be enabled. See above.
DOT Special for the Department of Transportation.
Note: When DOT mode is enabled, the TimeDelay settings operate the same as
in the RS485/422 mode.
Note: RS4xx mode must have Modbus RTU enabled, and TurnoffDelay set to at
least 4.
Setup Port Note: DO NOT change this setting unless the correct programming cable is
available for the new setting.
This setting determines which port, Main or Diagnostics, is used to enter the Setup
Main Menu.
Port Additional Information
Main Only The terminal is connected to the Main Data Port.
Diagnostics Only The terminal is connected to the Diagnostic Port.

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Both Ports The terminal may be connected to either port.
Setup mode is invoked by sending a "U" (capital) to the Diagnostics port or by
pressing/toggling the Set-up button/switch, if available. OEM boards may also
enter Setup when Pin 2 is grounded.
The Main Data Port is the RS232 port. The OEM modules use a 2-row, 2 mm
female connector. The diagnostic cable for this port (ASC2009DC) is available from
FreeWave.
TurnOn/OffDelay TurnOnDelay- Sets the delay between when the line drivers are turned on and
when the data leaves the data port. This setting can be adjusted for a 1-9 mS
delay.
TurnOffDelay- This setting specifies the time after the end of transmission of a
character to the RS485 bus that the transceiver stops driving the bus and releases
the bus to other devices. The units are ¼ of a character with a range of 0-9. An
entry of 4 means a delay equivalent to the duration of a full character. Default is
zero delay.
For data rates of 1200 bits/S or slower, avoid setting the TurnoffDelay parameter
higher than 4. At those rates the functionality of the microprocessor changes so
that a TurnoffDelay of 5 will have the same effect as if set to 1, and a setting of 6
will have the same effect as 2, and so on.
Note: TurnOffDelay must be set to a value of at least 4 for RS4xx operation.
FlowControl This menu specifies the hardware flow control for the Data port. The options for 0-3
are described below.
Port Additional Information
None Default - Uses software control (XON XOFF)
RTS
DTR
DOT

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Call Book
The Call Book is required to be used in Point-to-Point networks. The instructions provided in this section
are for Point-to-Point mode only.
Using the Call Book offers both security and flexibility in determining how FreeWave transceivers
communicate with each other.
Three settings must be made for two FreeWave transceivers to communicate in Point-to-Point mode:
1. The Master’s serial number must be listed in the Slave's Call Book or Slave Security is turned off
in the Slave.
2. The Slave’s serial number must be listed in the Master's Call Book.
3. The Master must be programmed to call the Slave.
The Call Book allows users to incorporate up to 10 FreeWave transceivers, and designate which Slave the
Master will call. To set the Entry to Call option, select the appropriate option in the drop down.

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Radio Transmission Characteristics
The Edit Radio Transmission Characteristics option allows the user to modify several different parameters
in the transceiver. Many of these parameters must be maintained throughout the network for proper
functionality.
Note: This menu is only for the sophisticated user who has a good understanding of the principles of
radio data transmission.
The settings for the Slave(s) not determined by the Master are RF Xmit Power, Slave Security, Retry
Time Out and Hop Table Size, Hop Table Version, and Hop Table Offset.
Note: Above image from LRS455. Configuration will be the same.
Edit Radio Transmission Characteristics
SETTING XMIT AND RCV FREQUENCIES
The 400MHz Data Transceiver has the option to operate in a Frequency Division Duplex mode by
transmitting on one frequency and receiving on another.
The LRS400S transceivers must be programmed to operate on the appropriate frequency. To program
the transceiver for single channel operation, enter the frequency, in Megahertz, into the TX and RX
Frequency slots.
If the transceivers are to operate in Frequency Division Duplex, the TX and RX Frequency slots will have
different frequencies assigned.

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(1) AND (2) MAX PACKET SIZE AND MIN PACKET SIZE
The Max and Min Packet Size settings and the RF Data Rate determine the number of bytes in the
packets. Throughput can be enhanced when packet sizes are optimized.
The following 3 tables provide the information to determine optimum setting values.
Minimum Packet Size Definition
Min Setting Min Packet Size
0 0
1 16
2 32
3 48
4 64
5 80
6 96
7 112
8 128
9 144
Maximum Packet Size (2 level FSK)
Max Setting Max Packet Size
0 32
1 48
2 64
3 80
4 96
5 112
6 128
7 135
8 135
9 135
Maximum Packet Size (4 level FSK)
Max Setting Max Packet Size
0 32
1 48
2 64
3 80
4 96
5 112
6 128
7 144
8 160
9 176

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(3) XMIT RATE
FreeWave transceivers utilize a Master Transmit Beacon to provide low current consumption in the slave
radios. The slave radios will turn their receiver off when no data is being passed.
The Xmit Rate setting allows the duty cycle of the Master Transmit Beacon to be changed. A setting of 0
is the highest duty cycle and a setting of 9 is the lowest duty cycle.
(4) RF DATA RATE
FreeWave transceivers have five settings for the RF Data Rate (1, 2, 3, 4, 5 ). RF Data Rate should not
be confused with the serial port Baud Rate.
Setting 2 should be used when the transceivers are close together and data throughput needs to be
optimized. Setting 3 should be used when the transceivers are farther away and a solid data link is
preferred over data throughput.
Note: In MultiPoint networks, the RF Data Rate must be set identically in all transceivers. Any
transceiver with an RF Data Rate different from the Master will not establish a link.
In Point to Point networks the Master’s settings take precedence over the Slave.
RF Data Rate Setting Occupied Bandwidth Modulation Level
1 50kHz 2-level GFSK
2 25kHz 4-level GFSK
3 25kHz 2-level GFSK
4 12.5kHz 4-level GFSK
5 12.5kHz 2-level GFSK
(5)RF XMIT POWER
The RF Xmit Power parameter allows the user to control the output transmit power up to two watts
(+33dBm).
Note: For use in applications requiring greater than 70% transmit duty cycle, the LRS400S series of
radios must be attached to an appropriate heat sync.
The following table shows RF TX output versus the RF Xmit Power setting.
RF Xmit
Power RF TX Power
(dBm)
RF Xmit
Power RF TX Power
(dBm)
RF Xmit
Power RF TX Power
(dBm)
RF Xmit
Power RF TX Power
(dBm)
10 +33 7 +30 4 +27 1 +24
9 +32 6 +29 3 +26 0 +23
8 +31 5 +28 2 +25

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(6) SLAVE SECURITY
Slave security is a feature which allows Slave transceivers to accept transmissions from a Master not
included in the Call Book. The default setting is 0 (Slave Security enabled) which means, only Masters in
the Slaves’ Call Book may link to that Slave.
Slave Security may be disabled (setting of 1) allowing any Master to call the Slave. Slave Security has no
effect in Point-to-MultiPoint networks where the Network ID is not set to 255.
Slave Security must be set to 1 when the unit is operating in Mode 6 Slave/Master switchable or a Point-
to-Point network where the Slave may need to accept calls from more than 10 different Masters. When
Slave Security is set to 1, the transceiver will accept calls from any other FreeWave transceiver.
Additional network security measures may be taken to prevent unauthorized access, such as changing
default settings for FreqKey, Hop Table or Frequency Zones.
(7) RTS TO CTS
Menu selection RTS to CTS in the Radio Parameters menu provides the option of allowing the RTS line
on the Master transceiver to control the CTS line of the Slave. This pass-through control can be enabled
in both Point-to-Point and Point-to-MultiPoint. In MultiPoint networks, the Master RTS line will control all
Slaves’ CTS lines. When enabled, the CTS line ceases to function as flow control. It is not recommended
to enable this feature when operating at RS-232 speeds above 38.4kB.
The default setting of 0 disables this function, where as a setting of 1 enables RTS-CTS control.
RTS-CTS setting 2 is described in detail in the application note #5437 DTR to CTS Line Alarm Feature.
With an RTS to CTS setting of 1, the Master senses the RTS line prior to all scheduled packet
transmissions. If the state has changed, the Master will then transmit a message to the Slave with the
new status. This transmission will occur regardless of data being sent. If data is ready to be sent, the
RTS status message will be sent in addition to the data. In Point-to-Point mode, the Master will continue
sending the new status message until it receives an acknowledgment from the Slave. In MultiPoint mode,
the Master will repeat the message the number of times equal to the Master Packet Repeat value in the
MultiPoint Parameters menu.
Master transmit times are completely asynchronous to the occurrence of any change of the RTS line; the
latency time from RTS to CTS is variable. The Max and Min Packet Size parameters in the Radio
Parameter menu determine this duration. Setting both parameters to their maximum value of 9 will
produce a maximum latency time of approximately 21 ms. At the minimum settings for Max and Min
Packet Size (0), the time will be approximately 5.9 ms. Please note that this latency can increase
significantly if packets are lost between the Master and Slave. In Point-to-MultiPoint mode, there is no
absolute guarantee that the state change will be communicated to all Slaves in the unlikely event that all
repeated packets from the Master do not get through to all Slaves.
Note: If DTRConnect is enabled and set to 2, the RTS to CTS feature will not work.
Note: If the DTRConnect is enabled and set to 1, RTS to CTS mode takes precedence over the
functionality of the CTS line on the Slave relating to the DTRConnect feature.
Note: The RTS to CTS option is only available in RS232 mode.
(8) RETRY TIME OUT
The Retry Time Out parameter in a Slave sets the delay the unit will wait before dropping the connection
to a Master in MultiPoint mode. The factory default is set at the maximum of 255. The maximum setting
means that if 1 packet in 255 is sent successfully from the Master to the Slave, the link will be maintained.
The minimum setting is 8. This allows a Slave to drop a connection if less than 1 in 8 consecutive packets
is successfully received from the Master.

LRS400S Data Transceiver Users Manual
LUM0025AA Rev A Version 1.0 20
On the other hand, the function in the Master is effectively the same. With a setting of 255, the Master
will allow a Slave to stay connected as long as 1 packet in 255 is successfully received at the Master.
The Retry Time Out parameter is useful when a MultiPoint network has a roving Master or Slave(s). As
the link gets weaker, a lower setting will allow a poor link to break in search of a stronger one.
Note: Setting Retry Time Out to 20 is recommended in areas where several FreeWave networks exist.
This setting will allow Slaves to drop the connection if the link becomes too weak, while at the
same time prevent errant disconnects due to interference from neighboring networks.
While intended primarily for MultiPoint networks, the Retry Time Out parameter may also be modified in
Point-to-Point networks. However, the value in Point-to-Point mode should not be set to less than 151.
(9) LOWPOWER MODE
The Lowpower Mode feature allows a MultiPoint Slave to consume less power. When set to 2 through 31,
the transceiver will sleep between slots. For example, at a setting of 2 the transceiver sleeps 1 out of 2
slots; at a setting of 3 the transceiver sleeps 2 out of 3 slots, and so on.
The following table shows the changes at different Lowpower Mode settings. The actual current draw
depends on many factors. The table below gives only a qualitative indication of supply current savings. A
low number reduces latency and a high number reduces current consumption.
Setting Description
0 Lowpower, disabled
1 LEDs dimmed, transceiver remains awake, transceiver is listening to the
Master’s transmissions on every slot, and transceiver’s data port is shut
down if the RTS line is deasserted (low). In this case, the transceiver
needs to be awakened before it will be able to send data to the Master.
2 LEDs dimmed, transceiver sleeps every other slot
3 LEDs dimmed, transceiver sleeps 2 of 3 slots
4-31 LEDs dimmed, transceiver sleeps the number of slots corresponding to
the setting. For example, with a setting of 31 the transceiver sleeps 30 of
31 slots.
IMPORTANT NOTES
1. Lowpower Mode is used only in MultiPoint Slaves using serial protocol. Power savings occur only
when the Slave is linked. There are no power savings when the Slave is transmitting data.
Lowpower Mode is of little value when a Slave has a constant, high throughput. MCUSpeed must
be set to ‘0’ and RF Data Rate must be set to ‘3’ for Lowpower Mode to operate properly.
2. To communicate to an RS232 port of a transceiver that is in Lowpower Mode, the RTS line must
be held high to wake it up. The transceiver will wake up within approximately 20 milliseconds of
when RTS goes high.
3. If the RTS line on the Slave is held high, the transceiver will remain in normal operation
regardless of the Lowpower Mode setting. Once RTS is dropped the transceiver reverts to the
Lowpower Mode.
If the transceiver has the DTRConnect option set to 1 or 2 and if the Lowpower Mode enabled (set to 1-
31), the RTS line on the transceiver must be asserted for the ‘DTRConnect’ feature to operate properly.
Current Draw
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