Murata WIT2411 Quick setup guide

Revision History
Revision Date Author Change Description
1 10/18/2005F. Perkins Rev C
2 11/19/2015 R. Willett Rev D, Reformatted to comply with new Murata V.I.
RFM products are now
Murata products.
WIT2411
2.4GHz
Spread Spectrum
Wireless Industrial
Transceiver
Integration
Guide
©2010-2015 by Murata Electronics N.A., Inc.
WIT2411 Integration Guide11/30/15
www.murata.com

Important Regulatory Information
Cirronet Product FCC ID: HSW-2411
IC 4492A-2411
Note: This unit has been tested and found to comply with the limits for a Class A digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference when the equipment is operated in a commercial environment. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed and used
in accordance with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at their expense.
FCC s MPE Requirements
Information to user/installer regarding FCC s Maximum Permissible Exposure (MPE) limits.
Notice to users/installers using the 24 dBi parabolic dish antenna in conjunction with all Murata
products.
FCC rules limit the use of this antenna, when connected to Murata products for point-to-point
applications only. It is the responsibility of the installer to ensure that the system is prohibited from
being used in point-to-multipoint applications, omni-directional applications, and applications where
there are multiple co-located intentional radiators transmitting the same information. Any other mode of
operation using this antenna is forbidden.
Notice to users/installers using the following fixed antennas, with Murata products:
Andrews 24dBi parabolic dish
Andrews 18dBi parabolic dish
Cushcraft 15dBi Yagi,
Mobile Mark 14dBi Corner Reflector,
Mobile Mark 9dBi Corner Reflector
The field strength radiated by any one of these
antennas, when connected to Murata products,
may exceed FCC mandated RF exposure
limits. FCC rules require professional
installation of these antennas in such a way
that the general public will not be closer than 2
m from the radiating aperture of any of these
antennas. End users of these systems must
also be informed that RF exposure limits may
be exceeded if personnel come closer than 2
mto the apertures of any of these antennas.
Notice to users/installers using the following mobile antennas, with Murata products:
Mobile Mark 12dBi omni-directional,
Mobile Mark 9dBi omni-directional,
MaxRad 5dBi whip,
Cirronet Patch antenna,
Ace 2dBi dipole,
Mobile Mark 2dBi Stub
The field strength radiated by any one of these
antennas, when connected to Murata
products, may exceed FCC mandated RF
exposure limits. FCC rules require
professional installation of these antennas in
such a way that the general public will not be
closer than 20 cm from the radiating aperture
of any of these antennas. End users of these
systems must also be informed that RF
exposure limits may be exceeded if personnel
come closer than 20 cm to the apertures of
any of these antennas.
©2010-2015 by Murata Electronics N.A., Inc.
WIT2411 Integration Guide11/30/15
www.murata.com

Declaration of Conformity
Warning! The RLAN transceiver within this device uses a band of frequencies that are not completely harmonized
within the European Community. Before using, please read the European Operation Section of the Products User’s
Guide for limitations.
0889 is the identification number of RADIO FREQUENCY INVESTIGATION LTD - Ewhurst Park, Ramsdell RG26
5RQ Basingstoke, United Kingdom – the Notified Body having performed part or all of the conformity assessment on
the product.
The WIT2411 to which this declaration relates is in conformity with the essential requirements of the R&TTE
directive 1999/5/EC and complies with the following standards and/or other normative documents:
For Interfaces For RLAN Transceiver
EN 55022
EN 55024 EN 300 328 EN 301 489 -1, -17
EN 60950
Canadian Department of Communications Industry Canada (IC) Notice
Canadian Department of Communications Industry Canada (IC) Notice
This apparatus complies with Health Canada’s Safety Code 6 / IC RSS 102.
"To prevent radio interference to the licensed service, this device is intended to be
operated indoors and away from windows to provide maximum shielding. Equipment (or
its transmit antenna) that is installed outdoors may be subject to licensing."
ICES-003
This digital apparatus does not exceed the Class B limits for radio noise emissions from
digital apparatus as set out in the radio interference regulations of Industry Canada.
Le présent appareil numérique n'émet pas de bruits radioélectriques dépassant les limites applicables aux appareils
numériques de Classe B prescrites dans le règlement sur le brouillage radioélectrique édicté par Industrie Canada.
©2010-2015 by Murata Electronics N.A., Inc.
WIT2411 Integration Guide11/30/15
www.murata.com

TABLE OF CONTENTS
1. INTRODUCTION ......................................................................................................................1
1.1. Why Spread Spectrum? ........................................................................................................1
1.2. Frequency Hopping vs. Direct Sequence..............................................................................2
2. RADIO OPERATION................................................................................................................5
2.1. Synchronization and Registration........................................................................................5
2.2. Data Transmission ...............................................................................................................6
2.2.1. Point-to-Point.............................................................................................................6
2.2.2. Point-to-Multipoint ....................................................................................................7
2.2.3. Handle Assignment....................................................................................................7
2.2.4. TDMA Operation.......................................................................................................8
2.2.5. Full Duplex Communication....................................................................................10
2.2.6. Error-free Packet Transmission Using ARQ............................................................10
2.3. Modes of Operation...........................................................................................................12
2.3.1. Control and Data Modes ..........................................................................................12
2.3.2. Sleep Mode ..............................................................................................................12
2.3.4. RF Flow Control Mode............................................................................................13
3. PROTOCOL MODES ..............................................................................................................14
3.1.3. Connect Packet.........................................................................................................16
3.1.4. Disconnect Packet (base only, receive only) ..........................................................16
4. MODEM INTERFACE............................................................................................................17
4.1. Interfacing to 5 Volt Systems ............................................................................................18
4.2. Evaluation Unit and Module Differences..........................................................................18
4.3. Three-Wire Operation........................................................................................................18
5. MODEM COMMANDS...........................................................................................................19
5.1. Serial Commands...............................................................................................................19
5.2. Network Commands..........................................................................................................20
5.3. Protocol Commands...........................................................................................................21
5.4. Status Commands ..............................................................................................................23
5.5. Memory Commands ..........................................................................................................24
5.6. Modem Command Summary.............................................................................................25
6. WIT2411 DEVELOPER’S KIT ...............................................................................................26
7. WinCOM...................................................................................................................................28
7.1. Starting the program ..........................................................................................................30
7.2. Function Keys....................................................................................................................33
7.3. WinCom Tools...................................................................................................................34
7.4. Script Commands...............................................................................................................36
7.5. Demonstration Procedure ..................................................................................................38
8. Troubleshooting........................................................................................................................39
©2010-2015 by Murata Electronics N.A., Inc.
WIT2411 Integration Guide11/30/15
www.murata.com

9. APPENDICES ..........................................................................................................................41
9.1. Technical Specifications....................................................................................................41
9.1.1. Ordering Information...............................................................................................41
9.1.2. Power Specifications................................................................................................41
9.1.3. RF Specifications.....................................................................................................41
9.1.4. Mechanical Specifications .......................................................................................41
9.2. Serial Connector Pinout.....................................................................................................42
9.3. Approved Antennas ...........................................................................................................42
9.4. Technical Support..............................................................................................................43
9.5. Reference Design...............................................................................................................44
9.6. Mechanical Drawing – WIT2411D ...................................................................................45
10. Warranty .................................................................................................................................46
©2010-2015 by Murata Electronics N.A., Inc.
WIT2411 Integration Guide11/30/15
www.murata.com

WIT2411
1. INTRODUCTION
The WIT2411 radio transceiver provides reliable wireless connectivity for either
point-to-point or multipoint applications. Frequency hopping spread spectrum
technology ensures maximum resistance to noise and multipath fading and robustness in
the presence of interfering signals, while operation in the 2.4GHz ISM band allows
license-free use and worldwide compliance. A simple serial interface supports
asynchronous data up to 921600 bps. An on-board 12 KB buffer and an error-correcting
over-the-air protocol provide smooth data flow and simplify the task of integration with
existing applications.
-Multipath fading impervious
frequency hopping technology
with 43 frequency channels
(2401-2475 MHz).
- Supports point-to-point or
multipoint applications.
- Meets FCC rules 15.247 and ETS
300.328 for worldwide license-
free operation.
- Superior range to 802.11 wireless
LAN devices.
- Transparent ARQ protocol
w/12KB buffer ensures data
integrity.
- Digital addressing supports up to
64 networks, with 62 remotes per
network.
- Low power 3.3v CMOS signals
- Fast acquisition typically locks
to hopping pattern in 2 seconds
or less.
- Selectable 8 mW or 18 mW
transmit power.
- Built-in data scrambling reduces
possibility of eavesdropping.
- Nonvolatile memory stores
configuration when powered
off.
- Smart power management
features for low current
consumption.
- Dynamic TDMA slot
assignment that maximizes
throughput.
Simple serial interface handles
both data and control at 115,200
or 921600 bps.
1.1. Why Spread Spectrum?
The radio transmission channel is very hostile, corrupted by noise, path loss and
interfering transmissions from other radios. Even in a pure interference-free
environment, radio performance faces serious degradation through a phenomenon
known as multipath fading. Multipath fading results when two or more reflected
rays of the transmitted signal arrive at the receiving antenna with opposing phase,
thereby partially or completely canceling the desired signal. This is a problem
particularly prevalent in indoor installations. In the frequency domain, a multipath
fade can be described as a frequency-selective notch that shifts in location and
intensity over time as reflections change due to motion of the radio or objects within
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WIT2411
its range. At any given time, multipath fades will typically occupy 1% - 2% of the
2.4 GHz band. This means that from a probabilistic viewpoint, a conventional radio
system faces a 1% - 2% chance of signal impairment at any given time due to
multipath.
Spread spectrum reduces the vulnerability of a radio system to interference from
both jammers and multipath fading by distributing the transmitted signal over a
larger region of the frequency band than would otherwise be necessary to send the
information. This allows the signal to be reconstructed even though part of it may be
lost or corrupted in transit.
Figure 1
Narrowband vs. spread spectrum in the presence of interference
1.2. Frequency Hopping vs. Direct Sequence
The two primary approaches to spread spectrum are direct sequence (DS) and
frequency hopping (FH), either of which can generally be adapted to a given
application. Direct sequence spread spectrum is produced by multiplying the
transmitted data stream by a much faster, noise-like repeating pattern. The ratio by
which this modulating pattern exceeds the bit rate of the baseband data is called the
processing gain, and is equal to the amount of rejection the system affords against
narrowband interference from multipath and jammers. Transmitting the data signal
as usual, but varying the carrier frequency rapidly according to a pseudo-random
pattern over a broad range of channels produces a frequency hopping spectrum
system.
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WIT2411
Figure 2
Forms of spread spectrum
One disadvantage of direct sequence systems is that due to spectrum constraints and
the design difficulties of broadband receivers, they generally employ only a minimal
amount of spreading (typically no more than the minimum required by the regulating
agencies). For this reason, the ability of DS systems to overcome fading and in-band
jammers is relatively weak. By contrast, FH systems are capable of probing the
entire band if necessary to find a channel free of interference. Essentially, this
means that a FH system will degrade gracefully as the channel gets noisier while a
DS system may exhibit uneven coverage or work well until a certain point and then
give out completely.
Because it offers greater immunity to interfering signals, FH is often the preferred
choice for co-located systems. Since direct sequence signals are very wide, they
tend to offer few non-overlapping channels, whereas multiple hoppers may
interleave with less interference. Frequency hopping does carry some disadvantage
in that as the transmitter cycles through the hopping pattern it is nearly certain to
visit a few blocked channels where no data can be sent. If these channels are the
same from trip to trip, they can be memorized and avoided; unfortunately, this is
generally not the case, as it may take several seconds to completely cover the hop
sequence during which time the multipath delay profile may have changed
substantially. To ensure seamless operation throughout these outages, a hopping
radio must be capable of buffering its data until a clear channel can be found. A
second consideration of frequency hopping systems is that they require an initial
acquisition period during which the receiver must lock on to the moving carrier of
the transmitter before any data can be sent, which typically takes several seconds. In
summary, frequency hopping systems generally feature greater coverage and channel
utilization than comparable direct sequence systems. Of course, other
implementation factors such as size, cost, power consumption and ease of
implementation must also be considered before a final radio design choice can be
made.
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WIT2411
As an additional benefit, RF spectrum has been set aside at 2.4 GHz in most
countries (including the U.S.) for the purpose of allowing compliant spread spectrum
systems to operate freely without the requirement of a site license. This regulatory
convenience alone has been a large motivation for the industry-wide move toward
spread spectrum.
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WIT2411
2. RADIO OPERATION
2.1. Synchronization and Registration
As discussed above, frequency hopping radios periodically change the frequency at
which they transmit. In order for the other radios in the network to receive the
transmission, they must be listening to the frequency over which the current transmission
is being sent. To do this, all the radios in the net must be synchronized and must be set to
the same hopping pattern.
In point-to-point or point-to-multipoint arrangements, one radio module is designated as
the base station. All other radios are designated remotes. One of the responsibilities of
the base station is to transmit a synchronization signal to the remotes to allow them to
synchronize with the base station. Since the remotes know the hopping pattern, once they
are synchronized with the base station, they know which frequency to hop to and when.
Every time the base station hops to a different frequency, it immediately transmits a
synchronizing signal.
When a remote is powered on, it rapidly scans the frequency band for the synchronizing
signal. Since the base station is transmitting over up to 43 frequencies and the remote is
scanning up to 43 frequencies, it can take several seconds for a remote to synch up with
the base station.
Once a remote has synchronized with the base station, it must request registration from
the base station. The registration process identifies to the base station the remotes from
which transmissions will be received and not discarded. Registration also allows tracking
of remotes entering and leaving the network. The base station builds a table of serial
numbers of registered remotes. To improve efficiency, the 24-bit remote serial number is
assigned a 6-bit “handle” number. Two of these are reserved for system use, thus each
base station can register 62 separate remotes. This handle is how user applications will
know the remotes. Note that if a remote leaves the coverage area and then re-enters, it
may be assigned a different handle.
To detect if a remote has gone offline or out of range, the registration must be “renewed”
once every 256 hops. Registration is completely automatic and requires no user
application intervention. When the remote is registered, it will receive several network
parameters from the base. This allows the base to automatically update these network
parameters in the remotes over the air. Once a parameter has been changed in the base, it
is automatically changed in the remotes. The parameters automatically changed are hop
duration and hop set.
At the beginning of each hop, the base station transmits a synchronizing signal. After the
synchronizing signal has been sent, the base will transmit any data in its buffer. The
amount of data that the base station can transmit per hop is determined by the base slot
size parameter. If there is no data to be sent, the base station will not transmit data until
the next frequency.
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