User's Manual

LoJack Corporation
200 Lowder Brook Drive
Westwood, MA 02090 USA
Voice: 1-781-326-4700
Fax: [phone]
www.lojack.com
CONFIDENTIAL AND PROPRIETARY
NRU Network Repeater Unit
The LoJack Network Repeater Unit (NRU) is a
low cost network device that can be used in a
LoJack Stolen Vehicle Recovery Network. The
NRU was designed to replace the obsolete
Tracker Repeater Unit (TRU), and the Packet
Decoder used for repeating. The NRU is now
available for 13 and 8 second networks.
An NRU can repeat downlink transmission
bursts it receives from either a Remote
Transmitter Unit (RTU), another NRU, or from
the network. It relays back any reply code
transmission it receives from an activated
Vehicle Locator Unit (VLU) as an uplink
message to a tower connected to the central
system. An NRU can also repeat uplink
transmissions from any nearby VLU or
repeaters. If connected via IP/broadband, the
NRU can forward to a central system any reply
code or uplink messages it hears.
Finally, the NRU can be used as a mobile
Installation Test Unit (ITU) for performing on-site
installation verification and routine inspection of
VLUs. When configured for ITU use, the NRU
can send properly timed and indexed test
command to the new VLU7 unit. This allows the
user to perform post-installation testing of the
VLU7 without the need to access the VLU7
ground wires. This powerful feature works both
inside and outside network coverage areas.
Product Description
The NRU is a self-contained unit in an indoor-
rated housing with mounting tabs, and includes
a built-in GPS receiver. The unit has a dedicated
serial interface, connectors for power and
antenna as well as relay contacts to drive an
external power amplifier.
The NRU fully supports VLU7 timing and
indexing requirements for downlink
transmissions for basic messages such as
Activation, Deactivation, Speed up, and
extended downlink messages such as Alt-
Deactivate.
The NRU can be used in conjunction with a
GSM modem. The NRU will not repeat
transmissions from a mobile transmitter with
pseudo dotting 15 in 13 second networks. It will
respond to either configuration or report request
messages from a mobile transmitter or from the
network.
NOTE:
The NRU is not base station certified. It is ETSI
certified for 13 Second Systems and FCC certified as a
mobile transmitter for 8 second Systems.
Product Highlights
• Network device that
o Repeats downlink and uplink
messages.
o Enables post installation
testing of VLU7 while in or
out of the network area.
• Available in two models
1. Full function – provides
complete NRU feature set.
2. ITU only - Supports only VLU
installation testing. No
network repeating features.