Technical BulletinProduct Information Overview

2 . 4 - G H zS P R E A DS P E C T R U MW I R E L E S SN E T W O R K

May 2001

M a s t e r L i n k ™ 2 .4 - G H z S p r e a d S p ec t r u m W i re l e ss Ne t wo r k

2.4-GHzSPREAD SPECTRUMWIRELESS NETWORK

From the innovators of DISPATCH®

Table of Contents

What is the MasterLink™ System?...........................................1The MasterLink™ System Difference ........................................1System Components ............................................................2

MasterLink™ 2.4-GHz Mobile Computer System .......................2MasterLink™ 2.4-GHz Repeater System.................................5

Deploying the MasterLink™ System .........................................7MasterLink™ System Advantages............................................8

Advantages of DSSS over FHSS ...........................................9Why Modular’s Design is Superior ......................................10

Specifications ..................................................................10Radio Channels & Regulations..............................................11Future Applications............................................................11Glossary.........................................................................12

Figure 1 MasterLink™ 2.4-GHz Wireless Network Overview ........2Figure 2 Haul Truck Showing Installation of MasterLink™

2.4-GHz Radios...................................................4Figure 3 MasterLink™ Hub Installed Inside Haul Truck Cab.........4Figure 4 MasterLink™ Hub Installed Inside NEMA Box

on Mobile Repeater..............................................6Figure 5 MasterLink™ Mobile Repeater.................................6

Abbrevi a ti ons and ac ronyms appe a ring in this doc u m ent are def i n ed in the Glossary.

Table of Figures

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What is the MasterLink™ System?

Modular’s MasterLink™ system is a dynamic, new 2.4-GHz spreadspectrum wireless communications network for mines. It is designed tosignificantly increase the amount of information that can be sent overthe radio channel, as compared with 9600-baud narrow-band systems.Using a radio based on Direct Sequence Spread Spectrum (DSSS) at 2.4GHz, the system attains a 2-Mb/s data rate. This yields an overallperformance increase of roughly 50 times over 9600-baud systems.This increase in bandwidth reduces data telemetry congestion in mineswith large equipment fleets and enables data-intensive use of the radiochannel for graphics, equipment-health diagnostics, equipment locationmonitoring, high-precision GPS applications—even emergingautonomous truck systems.

With MasterLink™, mines can minimize interference, take advantage ofthe latest mine productivity tools available, and maintain vital communications links between decision-makers and the equipment they monitor and control.

The MasterLink™ system’s DSSS technology provides a substantiali m provem ent in sign a l - to - n oise perform a n ce over conven ti onal modu l a ti ontechniques. Operating in the ISM 2.4- to 2.4835-GHz frequency band,the transmitted signal is spread within the frequency domain by usingan 11-bit Barker sequence chipping code to obtain a transmissionbandwidth of 22 MHz and data rates of 1 Mb/s with DBPSK and 2 Mb/swith DQPSK. The received signal is strengthened by a processing gain of 10.4 dB, thereby increasing the signal’s resistance to interference.

This improved radio performance and increased bandwidth provides thewi reless capac i ty for high - va lue app l i c a ti ons that boost mine produ ctivi ty.MasterLink™ enables:

» Intensive use of high-precision GPS applications, which provide real-time distributed data for shovels, loaders, drills, and dozers, as well asmine-wide distribution of original planned and actual topography.

» Mobile Foreman app l i c a ti on s , with access to current high - prec i s i on GPSand dispatching data anywhere, including low-latency DISPATCH®operations.

» Interactive maintenance management systems with high-speed,on-line telemetry and use of commercial off-the-shelf (OTS) PCsand handheld computers.

The MasterLink™ System Difference

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System Components

Figure 1MasterLink™ 2.4-GHz Wireless Network Overview

The MasterLink™ system consists of two major subsystems: a 2.4-GHzmobile computer system and a 2.4-GHz repeater system. The primaryhardware includes MasterLink™ Hubs, radio-antenna modules, andmobile repeater stations. MasterLink™ uses several small repeaters thatare each a fraction of the cost and size of conventional repeater units.Figure 1 shows the typical system architecture.

MasterLink™ 2.4-GHz Mobile Computer System

Where the application dictates, each truck, shovel, dozer, drill, or othermine equipment in the network requires a mobile computer system.This system consists of:

» Two MasterLink™ 2.4-GHz radio-antennas

» A MasterLink™ Hub

For IntelliMine® applications, including DISPATCH®, a CAN-basedColor Graphics console (CGC) and a GPS antenna are essential onmobile units and provide the equipment operator with an intuitiveuser interface and GPS location, respectively.

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A unique arrangement using two radio-antennas with patented antennadesign provides full 360-degree coverage around mobile equipment.This sys tem de s i gn overcomes the practical mounting limitati ons assoc i a tedwith single-antenna deployment because each radio-antenna provides1 9 0 - degree hori zontal beam widths that com bine to provi de com preh en s ivecoverage. Dual radios combat multipath effects in areas where oneradio-antenna alone would be unable to receive the signal. Dual radiosalso enable reception when line-of-sight (LOS) coverage is not possible.On a typical truck installation, for example, the radios are mounted oneeach on the front left and right corners of the truck (Figure 2). In thedual antenna system utilized by MasterLink™, both radios receivenetwork messages, t h ereby increasing sys tem rel i a bi l i ty thro u gh an ef fectivel evel of redu n d a n c y. Intelligent signal detection allows the system totransmit only on the radio-antenna that has optimum transmission tothe repeater, ensuring reliable and complete coverage.

The MasterLink™ system is compliant with IEEE 802.11 standards.

The mobile computer system’s rugged design provides environmentalprotection against the harsh environments common to mine sites. Boththe Hub and radios are watertight and sealed to NEMA standards toprotect against such environmental hazards as dust, moisture, andextremes of heat and cold. Shock mounts provide vibration protection.

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The Hub and radio-antenna units are small and lightweight, enablingeasy install a ti on on any veh i cl e . Ad d i ti on a lly, the Hub (Figure 3) iss i gn i f i c a n t ly faster than the conven ti onal rad i o - equ i pped Hu b,providing smoo t h er tra n s i ti on of d a t a , less net work con ge s ti on ,and increased productivity.

Two digital I/O ports (contact closures) available on the Hub acceptdiscrete inputs from devices such as foot switches or tray-up switches.Status LEDs on the top of the Hub convey important information, suchas power, status of both radio-antenna links, GPS availability, and radiocommunications network status. Additionally, the GPS LED flashes the

System Components

Figure 2Haul Truck ShowingInstallation of MasterLink™2.4-GHz Radios

Figure 3MasterLink™ Hub InstalledInside Haul Truck Cab

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number of satellites currently being tracked. The LED signal is a convenient visual indicator that provides immediate notice of properoperation and change of status, and allows maintenance personnel totake the appropriate action. This saves time and money by providing aquick diagnostic indication of system performance. The Hub electronicsand associated connectors support the following functions:

MasterLink™ 2.4-GHz Repeater System

Rather than installing one or two conventional narrow-band repeaters,the Ma s terLink™ sys tem uses several small repe a ters . The repe a ters provi deLOS radio covera ge within the de s i red covera ge are a . Ad d i ti onal repe a terscan provide redundancy, improving system reliability. Modular offers am obile vers i on of the repe a ter to easily dep l oy covera ge to new work are a s .

E ach repe a ter ex tends the base stati on’s area of covera ge and com mu n i c a te swith the base station by way of other repeaters or directly by way of afiber optic cable, if available.

The base station uses redundant radios to ensure continued operationin the event of signal loss. Likewise, primary routing paths betweenrepeaters incorporate alternative routing paths to achieve coverageshould a lost signal situation occur. Additional repeaters can be addedto provide redundancy to whatever extent is desired.

The repeater system consists of:

» An environmental enclosure containing a MasterLink™ repeater Hubwith a 1-watt, DSSS, 2.4-GHz radio

» An omnidirectional 6-dB antenna with a 12-, 18-, or 24-foot mast

» A lightning diverter

» GPS capability to facilitate system deployment and coverage analysis

The repeater Hub resides in a weatherproof enclosure (Figure 4). Theentire unit is attached to a support pole with brackets. The electronicsare similar to the mobile computer system Hub and reside in a similarenclosure.

Both fixed and mobile versions of the 2.4-GHz repeaters are available.The mobile version (Figure 5) permits rapid deployment to achieveadditional coverage or improve coverage as the mining progresses.

Connector/Ports Quantity Notes

2.4-GHz Radio 2 Connectors for 11-Mb/s data link to the radio-antennasSLIP 1 Serial port for configuration and updatePower 1 Hub source power (includes accessory switch input)CAN 2 CAN device connections with 24-V powerReserved 1 For future “Modular Ready™” interface applicationsGSP 1 Generic Serial Processor Expansion with 15-V isolated powerDigital I/O 1 2 digital inputs with 24-V wetting voltage for contact-

closure-type devices such as foot switchesGPS RF Input 1 TNC female connector for the GPSantenna

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System Components

Figure 5MasterLink™ MobileRepeater

Figure 4MasterLink™ Hub InstalledInside NEMA Box on Mobile Repeater

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The omnidirectional antenna greatly reduces the need for realignmentwith changing mine topography.

Other options for the repeater system include:

» Steel mounting base, including three stabilizing outriggers withadjustable jack stands and a support for the antenna mast, designedto fit the mobile trailer or as a stand-alone fixed unit

» Wheel option consisting of a steel frame with two 15-inch wheels andstandard trailer hitch that converts the fixed configuration to amobile configuration

The following power options are available for the repeater system:

» ac-to-dc power system with surge protector to support 50 and 60 Hzin the 100- to 200-V ac and 200- to 240-V ac ranges

» Solar panels, with a 24-V battery backup and surge protection,available in 150- and 300-W power ratings

Installation of the 2.4-GHz MasterLink™ spread spectrum wireless n et-work begins by cre a ting a Di gital Eleva ti on sof t w a re model from mine-provided topology data. Using this model, an LOS analysis is performedto obtain an estimate of the number of repeaters required, and theirl oc a ti on s , in order to provi de the de s i red level of covera ge . As a final step,Radio Frequ ency (RF) prop a ga ti on is mapped , ef fectively ‘f i n e - tu n i n g’ t h erepe a ter loc a ti on s .

In s t a lling the Ma s terLink™ sys tem hardw a re on mine equ i pm ent con s i s t sof i n s t a lling shock - resistant mounting brackets in pre - de s i gn a ted loc a ti on s ,and then mounting the radio-antennas and Hubs to the brackets. Cablesare then routed and the connections are made and checked. Neither theHub nor radios require being opened.

The repeater base and trailer require some assembly; then the antennamast and brackets are installed. After all the hardware is mounted, cableconnections are made and checked.

Solar panels ch a r ge the batteries in the 24-V solar- powered repe a ter sys temuntil they reach 28.2 to 29.0 V. Note, the batteries must be charged to25.4 to 26.6 V dc before the load is applied. When the batteries dischargeto 22.4 to 23.6 V, the load discon n ect s . On a fully ch a r ged set of b a t teri e s ,the repeater can continue operating without sunlight for several days.

As each mobile com p uter sys tem and repe a ter sys tem is install ed , opera ti n gand application software is downloaded from a laptop through the HubSLIP port . Th en the RF links to the base stati on or another com mu n i c a ti on sn ode are ch ecked to verify thro u gh p ut is accept a bl e .

The status of any and all repeaters in the system configuration can bemonitored from the central computer.

Deploying the MasterLink™ System

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DSSS technology at 2.4 GHz is an improvement over the more commonFHSS (Frequency Hopping Spread Spectrum) radio. It offers muchqu i cker synch ron i z a ti on time (lock - on ) , and is also mu ch less su s cepti bl eto interference. The range of transmission is substantially greater and itprovides a 2-Mb/s data transmission rate.

The system provides 1-watt of transmit power, which is 10 times morepowerful than most commercially available radios and permits the use ofcustom 190-degree, horizontal beam width, integrated antennas for full-a rea covera ge . The com bi n a ti on of i n c re a s ed power and paten ted anten n adesign makes available an 8-mile line-of-sight (LOS) node-to-noderange with 10 dB of fade margin in a full 360-degree antenna pattern.Ot h er com m erc i a lly ava i l a ble radio sys tem s , using high - gain unidirecti on a lantennas, are generally limited to very directional point-to-point links toachieve the same 8-mile ranges. In a typical MasterLink™ system usingmultiple repeaters, technicians can cascade many 8-mile nodes togetheron the same network, increasing the effective range even farther.

The 2-Mb/s data rate enables data intensive use of the radio channel forgraphics, on-line diagnostics, high-precision GPS applications, and theprecise data requirements of autonomous truck systems.

MasterLink™ is compliant with the IEEE 802.11 standard, a provenprotocol, which provides interoperability with other devices, such as alaptop or PDA with a wireless network card; seamless user support forroaming between multiple coverage areas; and high available bandwidththat utilizes a complex collision avoidance scheme, which allows thenetwork to perform well even when the usage is very high.

The small Hub size facilitates easy installation in tight quarters.

The integrated power protection and distribution scheme withimproved shielding provides interference-free and highly reliable operation. Each unit is completely shielded against EMI/RFI(Electromagnetic Interference/Radio Frequency Interference) andincludes internal power conditioning and isolation.

Installing the MasterLink™ system is expedient, in part, because thesystem operates in the license-free ISM frequency band. This eliminatesthe po ten tial del ays assoc i a ted with the radio frequ ency license app l i c a ti onprocess. Also, there are no licensing fees.

The system’s inherent architecture makes adding repeaters to aninstalled system practically effortless, and mobile repeaters are easilydeployed to cover new work areas as the mine’s topography changes.

MasterLink™ System Advantages

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Advantages of DSSS over FHSS

The primary benefit of DSSS over FHSS is that it has a significantperformance advantage in its power and range capability, which permitsthe DSSS radio to have more than twice the range and coverage overFHSS. Additional range and coverage means an 8-11 mile range ispossible using a 360-degree omnidirectional antenna with DSSStechnology. FHSS systems typically lessen range limitation by usingdirectional antennas, which result in a “cone” of coverage that must bedirected toward a specific location. This makes full mine coverage withFHSS difficult and requ i res more repo s i ti oning in order to accom m od a teroute changes. Because both technologies are limited to 1-watt of peakoutput power—most off-the-shelf radios only have 100-mW power—DSSS is the better choice.

DSSS also has the capability of higher data rates, faster synchronizationto channel changes, and rejection of narrow-band interference. TheDSSS radio has the advantage when transferring data because it can chipsequence in just a few bits, whereas an FHSS radio will spend more timeto search for the signal and lock on to it, resulting in longer latency time.Modular’s MasterLink™ system with DSSS provides for an additional10.4 dB of improvement to the SNR (Signal-to-Noise Ratio), whichhelps get more data through. FHSS does not spread each bit of the signalwith a chipping code and thus there is no signal processing gain. Wheremultiple networks are required, FHSS supports more independentnetworks than DSSS—thirteen instead of three—and rejects broadbandinterference better.

In an open environment such as a mine, interference should not be aproblem for either type of radio system. Moreover, the number ofnetworks located within the mine site is not a significant factor becauseMasterLink™ with DSSS technology only requires one network (andthus one channel) for operation. Because a mine requires only a singlenetwork, DSSS is the ideal choice. Modular chose DSSS technology forits MasterLink™ network to provide the mining industry with the mostrobust system available that meets the wireless communications needsspecific to the mine-site environment.

Additionally, DSSS is fast becoming the de facto standard for the wirelesscommunications industry.

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Why Modular’s Design is Superior

Modular’s MasterLink™ system increases the performance of high-precision applications. With a design based on the IEEE 802.11 standard,MasterLink™ utilizes the strength of a pro tocol te s ted and provent h ro u gh o ut the wi reless net work indu s try. From the ground up, the sys temhas been engineered to provide best-of-breed integrated technology,a ll owing a mine site to dep l oy and ad just qu i ck ly to ch a n ging con d i ti on s .

MasterLink™ is a fully scalable communications backbone upon whichyour mine’s network system can grow. As the industry leader in minemanagement technology, with over 20 years of experience in the miningi n du s try, Modular con ti nues to provi de proven rel i a bi l i ty and co s t - s avi n gsolutions. We stand behind our products. The MasterLink™ system isdesigned to withstand worst-case mining conditions in some of theroughest environments in the world, and it is customizable for each site.

MasterLink™ System Advantages

REPEATER SYSTEM TYPICAL UNITS

Power Inputs (from solar array or ac/dc converter) 24 (nominal) volts dcSolar Panel Power Rating 150 or 300 wattsPower Requirement 24 volts dcMast Height Options 12, 18, or 24 feet

MOBILE COMMUNICATIONS SYSTEM TYPICAL UNITS

Voltage Input Range 12 or 24 (nominal) volts dcPower Usage 20 to 50 wattsRadio Dimensions 8.7 X 6.5 X 13.5 inchesRadio Weight 3.5 poundsHub Dimensions 14.0 X 10.3 X 3.7 inchesHub Weight 9.5 poundsOperating Temperature Range -30 to +70 Celsius

RADIO OPERATION & PERFORMANCE TYPICAL UNITS

Output Power Range (8 Bit DAC = 256 steps) 2-30 dBmTX Distance Range (set to 30 dBm) 8.0 milesB.E.R. (Bit Error Rate) 1 X 10-6 bitsReceiver Sensitivity ( = Noise Floor + SNR) -92.87 dBmDynamic Range (TX PWR - Receiver Sensitivity) 122.87 dBTX & RX Data Rates using DQPSK 2 Mb/sTX & RX Data Rates using DBPSK 1 Mb/sChipping Code 11 bitsData Scrambling EnabledAntenna gain 6 dB

(360-degree horizontal coverage mobile repeater)

Specifications

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Radio Channels & Regulations

Future Applications

Regulatory Domains

X'10' X'20' X'30' X'31' X'32' X'40'Frequency FCC IC ETSI MKK

ID (MHz) U.S.A. Canada Europe Spain France Japan

1 2412 X X X - - X2 2417 X X X - - X3 2422 X X X - - X4 2427 X X X - - X5 2432 X X X - - X6 2437 X X X - - X7 2442 X X X - - X8 2447 X X X - - X9 2452 X X X - - X10 2457 X X X X X X11 2462 X X X X X X12 2467 - - X - X X13 2472 - - X - X X14 2484 - - - - - X

As of April 2001. Please contact your local regulatory domain agency for the most up-to-date information.

USA: ISM BAND 2400 - 2483.5 MHz (same for Europe – ETSI)Power 1-watt maximum (30 dBm) for DSSS with

6 dB of antenna gain

JAPAN: ISM BAND 2400 – 2497 MHzPower 10 mW / MHz

The radio system operates onany legal channel on a mine-by-mine basis (completely atthe customers’ discretion). With this multichannel capability,a mine could operate a separateand independent system usinganother channel. The transmitspectrum bandwidth of achannel is 17 MHz centeredon the channel frequency.

With the MasterLink™ system, the future is wide open. Consider thepossibilities for additional service applications to improve mine-siteproductivity, such as IP addressing, improved routing, and ObjectMessaging (OMS), all of which will greatly improve how data movesthrough the site and potentially provide an integral link to outsidenetworks and the Internet. Imagine e-mail and messaging services builtin to the system, intranet and Internet connectivity that enables access toaccount information from your vendor and OEM sites, or access tocorporate enterprise data. Would you like to be able to predict when apart will fail, enabling repairs to be scheduled well in advance of acom p l ete bre a k down , t h ereby, s aving time and reducing co s t ly rep l acem en t sthat may not be necessary? Envision your mine site running onAutonomous Haulage, or obtaining data from the site on your handheldcomputer or PDA (Personal Digital Assistant) without ‘plugging in.’These are only some of the future applications that may become commonplace over the next decade. What does the future hold? No onek n ows for cert a i n , but Modular wi ll be there con ti nuing to of fer innova tivesolutions and cutting-edge technology that provide mine sites across theworld with incre a s ed cost savi n gs and a maximized retu rn on inve s tm en t .We find the prospects exciting! Want to come with us? What will thefuture be like at your mine site?

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Autonomous Haulage The navi ga ti on of an unmanned veh i cle using po s i ti on - b a s ed path track i n g.Modular’s Autonomous Haulage project utilizes the IntelliMine® minemanagement system, including DISPATCH®, to act as the real-timesupervisory system for unmanned haul trucks.

Barker Sequence The 11-bit chipping code required for compliance with the IEEE 802.11standard for wireless LANs.

Baud A measu re of the nu m ber of times per second a signal in a com mu n i c a ti on schannel varies.

BER Bit Error Rate.

CAN Controller Area Network.

CGC Color Graphics Console.

Chipping Code A particular bit pattern in wh i ch each tra n s m i t ted bit is mu l ti p l i ed . Th i sbit pattern (or bi n a ry sequ en ce) spre ads the tra n s m i t ted signal over a wi def requ ency ra n ge . The receiver uses the same ch i pping code to recon s tru ctthe ori ginal sign a l . This recon s tru cti on provi des the 10.4-dB processing ga i n .

DAC Digital-to-Analog Converter.

dB Dec i bel ; a loga rithmic unit used to ex press the rel a tive differen ce in powerusually between acoustics or electric signals.

DISPATCH® The on ly tru ly proven dispatching sys tem . Cre a ted by Modu l a r, it integra te sthe complete mining process by providing automatic, optimized haultruck assignments.

DBPSK Di f feren tial Bi n a ry Phase Shift Keyi n g, su pports 1-Mb/s data ra te .

DQPSK Di f feren tial Quad ra tu re Phase Shift Keyi n g, su pports 2-Mb/s data ra te .

DSSS Di rect Sequ en ce Spre ad Spectru m . A form of s pre ad spectrum tech n o l ogythat uses a very fast bi n a ry bit stream (ch i pping code) to mu l ti p ly (or mix)a gainst a modu l a ted RF data sign a l . The process splits each bit of tra n s m i t teddata into many fra gm en t s , wh i ch re sults in the signal being spre ad over amu ch wi der frequ ency band. This re sults in a mu ch more robust andi n terferen ce - resistant signal than the ori gi n a l , u n s pre ad ,m odu l a ted , R Fdata sign a l .

EMI/RFI Electromagnetic Interference / Radio Frequency Interference.

FHSS Frequency Hopping Spread Spectrum.A form of spread spectrumtech n o l ogy that relies on ‘h opp i n g’ bet ween ch a n n el s , using different carri erf requ encies at different ti m e s . The data signal is modu l a ted with a narrow -band c a rri er signal that ‘h op s’ in a ra n dom but known sequ en ce fromf requ en c y to frequency as a function of time.

GHz Giga-hertz; one billion cycles per second.

GPS Global Positioning System. Developed by the United States Departmentof Defense to simplify acc u ra te navi ga ti on . It uses satell i tes and com p utersto calculate precise positions on Earth.

GSP G en eric Serial Proce s s or. A built-in com pon ent of Modu l a r ’s In tell i Mi n e ®and DISPATC H ® systems that provide the serial communicationsinterface to third-party health-monitoring devices.

Glossary

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IEEE In s ti tute of E l ectrical and Electronics Engi n eers . Fo u n ded in 1884, the IEEEis an or ga n i z a ti on com po s ed of en gi n eers , s c i en ti s t s , and stu den t s . Be s tk n own for devel oping standards for the com p uter and el ectronics indu s try,in parti c u l a r, the IEEE 802 standards for local area and wi reless net work s .

IntelliMine® Modular’s innovative mine management system that optimizes theperformance of a mine’s critical assets. IntelliMine® incorporatesModular’s world-renowned DISPATCH® system and is the only ful lyi n tegra ted sys tem ava i l a ble for both open pit and under ground opera ti on s .

ISM Industrial, Scientific, and Medical bands. An FCC modification of part15 of the radio code that aut h ori zed licen s e - f ree opera ti on in the fo ll owi n gISM bands: 902 - 928 MHz, 2.4 - 2.4835 GHz, and 5.725 - 5.850 GHz.

LED Light-Emitting Diode.

LOS Line-of-Sight.

Mb/s Megabits per second; a data rate. One million bits per second.

MHz Mega-hertz; one million cycles per second.

Multipath Interference caused by reflected GPS signals arriving at the receiver,typically as a result of nearby structures or other reflective surfaces.Signals traveling longer paths produce higher (erroneous) pseudorangeestimates and, consequently, positioning errors.

NEMA National Electrical Manufacturer’s Association.

OTS Off-the-Shelf.

PDA Personal Digital Assistant.

PN Pseudo Noise. A digital signal with noise-like properties. Also a wide-band modu l a ti on , wh i ch imparts noi s e - l i ke ch a racteri s tics to an RF sign a l .

PWR Power.

Real time Re a l - time com mu n i c a ti ons in wh i ch inform a ti on sent is received instantlyby the other party in a continuous stream. For example, telephone callsare real time; e-mails are not.

RF Radio Frequency. Generally a frequency from 50 kHz to 3 GHz. RF isnormally referenced whenever a signal is radiated through the air.

RX Receive.

SLIP Serial Line In terf ace Pro toco l . Serial port on the Hub for configurationand update.

SNR Signal-to-Noise Ratio.

Spread Spectrum An RF modulation technique. Spreads a signal bandwidth over a widera n ge of f requ encies for tra n s m i s s i on , and then de - s pre ads it to the ori gi n aldata bandwidth at the receiver.

Synchronization time The time it takes to lock on to and begin receiving a signal.

TNC Threaded Normalized Connector.

TX Transmission or transmit.

Every effort has been made to provide reliableresults regarding information comparingModular’s technology and/or products withcompetitive offering(s). In addition, whereverpossible, the latest available specificationsheets and other material have been used, withthe full understanding that these are subject tochange without notice. This document maycontain forward-looking statements. This document is the sole property of ModularMining Systems, Inc. Any reproduction of thisrelease (or other copyrighted material) withoutthe foregoing explanation and express permission of Modular Mining Systems, Inc. is p r o h i b i t e d .

©2001 Modular Mining Systems, Inc.All other trademarks are the property of theirrespective owners.

TB-MLSU-US-01-r1May 2001

Printed in U.S.A.

Modular Mining Systems, Inc.3289 E. Hemisphere LoopTucson, AZ 85706-5028U.S.A.

tel: +1 (520) 746-9127fax: +1 (520) 889-5790www.modularmining.com

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