User's Manual

GlobalTrak ™ GT Lite Operation and Maintenance Manual
GT Lite defaults to US frequencies. Switching to other frequencies is handled by the main
application using the time since last transmission and GPS data. Rough GSM based geo-
zones reside in GT Lite memory. After a failed GSM transmission, the application uses these
geo-zones to determine which frequencies to search. If no GPS information is available or if
there are 5 consecutive failed transmissions, the application will switch back and forth
between US and EU frequencies every other transmission attempt until a successful transmit.
If the device is determined to be in a cellular dead zone (e.g. on a vessel at sea), the
application code delays frequency searching until entering a geo-zone with cell
communications.
The frequencies are also selectable locally at the device. If US or European frequencies are
selected at the device, GT Lite will default to the selected frequency.
Orbcomm Satellite
GT Lite has the option to add Orbcomm satellite communication for near real time
communications anywhere in the world. The ORBCOMM system is a Low Earth Orbit (LEO)
constellation that allows two-way communication to and from mobile or fixed Subscriber
Communicators (SCs). In most applications, a message or other data is first generated by an
SC. From that source, the data is transmitted to the nearest ORBCOMM satellite. The
satellite downlinks the data to the selected Gateway Earth Station (GES), which then
transmits the data to the desired Gateway Control Center (GCC). Within the GCC, the data is
processed and forwarded to its ultimate destination by the Gateway Message Switching
System (GMSS). The destination may be another SC, a pager, a corporate resource
management system or any personal or business e-mail or Internet address. If the satellite is
not in view of any GES, it will store the message until a GES is seen and forward it at that
time. For more information about the Orbcomm option, please consult Section XXXXXXX.
Iridium Satellite
GT Lite has the option to add Iridium satellite communication for real time two way
communications anywhere in the world. The Iridium system is a LEO constellation that allows
real-time, two-way communication between the GT Lite and the IMB. The data is passed
from satellite to satellite before reaching an earth station, so there is no need for a store and
forward system. For more information about the Iridium option, please consult Section
XXXXXX.
ZigBee Wireless
The ZigBee wireless link is a low-cost, very low-power, two-way wireless communications
standard. The IEEE 802.15.4 standard defines the lower two layers: the physical layer and
the medium access control (MAC) sub-layer. The ZigBee Alliance builds on this foundation by
providing the network layer and the framework for the application layer.
The IEEE 802.15.4 standard has two physical layers that operate in two separate frequency
ranges: 868/915 MHz and 2.4 GHz. The lower physical layer covers both the 868 MHz
European band and the 915 MHz band that is used in countries such as the United States and
Australia. The higher frequency layer, 2.4 GHz, is used virtually world-wide, and is the band
to be used for GT Lite functions.
Mesh Communications
ZigBee allows GT Lite includes wireless communications with enabled devices and other GT
Lites. The mesh network configuration allows buried GT Lite devices may be able to
Prepared: R. Straz Date: July 25, 2007 Page 20 of
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