User's Manual

VTU-3 Users Guide
Page 17 of 18
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LoJack Timed Remote Transmitter Unit (LoJack TRTU)........Synchronous LoJack TRTUs that incorporate
precise timing control, facilitating the use of time-windowed synchronization of VLUs.
The TRTU system uses different timing than the LoJack system
LoJack Unit (LJU)A LoJack vehicle mounted module, which can be activated by a compatible system
and tracked by a tracking receiver. Also referred to as Vehicle Transceivers (VTs) or
Vehicle Location Units (VLUs).
Low Current configuration (LC)........A low current model, configured during manufacture, powered by 12V.
A VLU-5N in this configuration will maintain a low lifetime average current even
when not synchronized to a TRTU system.
LPRT LPRT (Listening Post/Remote Transmitter) is the tower site computer. This is the
equivalent of the RTU (Remote Transmission Unit) upgraded with additional
functionality.
Motion Sensing Module (MS)....... An electronic module that can sense the presence of vehicle motion, and
issue a "Movement Alert" message via the VLU-5N's Motion Sensor Interface. Also
may be described as an Early Warning Detector (EWD)
Motion Sensor Interface (MSI) The interface pins on the VLU-5N that connect to the Motion Sensor Module.
If both pins are pulled high by the MSM, the VLU-5N will register a motion event and
act accordingly.
Non-Timed Remote Transmitter Controller (Non-TRTU)..An RTU system that does not adhere to the strict
timing requirements of the synchronous TRTU system (see Timed TRTU).
Output
Packet Decoder... An Minimum Shift Keying transponder that decodes Reply Codes; and can act as a
Repeater
Periodic Uplink Response Rate.........Certain Uplink messages are sent by the VLU-5N at a Periodic Uplink
Response Rate. These messages are sent n times at intervals of in minutes then x
times at intervals of y minutes (where n, in, x, and y are configurable parameters).
The broadcast of the message will continue until the unit sends n and x messages
OR it receives an appropriate BASE ACK. The reception of the appropriate BASE
ACK indicates that the message has been received by the system and transmissions
can cease. The rates (n, in, x, and y) are global parameters and all messages that
use the Periodic Uplink Response Rate use the same values (in a particular VLU-5N).
"Out of ITU" message uses just the x and y values.
Portable Configuration A very low current model, configured during manufacture, powered by a
dedicated battery and a transmitter battery used only to power the transmitter. The
Portable configuration will maintain a very low lifetime average current even when
not synchronized to a TRTU system.
Portable RTU Remote Transmission Unit designed to be easily moved
Primary Power .... Primary power is used with the Adaptive, Full Service, and Low Current models to
denote vehicle power. Primary power in the Portable configuration is supplied by the
3.6 V dedicated battery.
Remote Transmitter Unit (RTU) .......... Part of the system infrastructure which receives commands from the
system central computer via phone lines or other communication techniques and
broadcasts packets to VLU-5Ns over the RF channel according to the RF
Communications Specification.
Repeater Tracker Repeater Unit (TRU is obsolete)
Reply Code The code associated with a LoJack Unit that is used to speed-up a unit. The reply code is
transmitted from a LoJack Unit when it is activated. The reply code is received by
Police Trackers.
RF Amplifier Manufacturer of UK RF Amps
SAC A Sector Activation Computer is a LoJack Computer that calls the Listening Post/Remote
Transmitter’s for LoJack Unit Activations, Speed-ups (Tracks), and Deactivations,
based on commands from a Law Enforcement Computer.