User's Manual

Galaxy Tracking Systems, L.L.C. VTU User’s Guide
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Use or disclosure of data contained on this sheet is subject to the restriction on the title page of this report.
While in this mode, the VTU will transmit an OUT OF SERVICE response to all
commands except the IN SERVICE command.
When OUT OF SERVICE, all in-vehicle alarms are disabled, (see SELF-ACTIVATION).
8.2.1.1 OUT OF SERVICE Operating Mode Commands
The commands available with OUT OF SERVICE follow.
IN SERVICE Command
Upon receipt of an IN SERVICE command, the VTU will change operating mode to IN
SERVICE and transmit an IN SERVICE message to report the change in mode. The
VTU is set operational by this command and can begin to report position, time, status
and on-board alarms.
8.2.2 IN SERVICE Operating Mode
When commanded IN SERVICE, the VTU will respond with a single IN SERVICE
message at the exact time indicated in the command packet. While IN SERVICE, the
VTU transmits an IN SERVICE message in response to all commands. The VTU will
also transmit an IN SERVICE message in response to alarms activated by the vehicle
operator (e.g., SOS) or events (e.g., unauthorized movement).
8.2.2.1 IN SERVICE Operating Mode Commands
The commands available with IN SERVICE follow.
OUT OF SERVICE
The VTU will change operating mode to OUT OF SERVICE and transmit an OUT OF
SERVICE message to report the change in mode. On-board alarms are disabled. All
subsequent commands (except IN SERVICE) are answered with an OUT OF SERVICE
message.
ONE SHOT
The one-shot command is a request for a single position / status report. The VTU
responds with a single IN SERVICE message containing current status, position, speed
and time.
ACTIVATE TRACKING
The ACTIVATE TRACKING command causes the VTU to begin regular position
reporting. The rate and the exact moment at which the VTU reports and the frequency
on which the report is transmitted are all contained in the command. Tracking mode is
used to monitor vehicle movements and status in real-time and to vector pursuit
vehicles to intercept points.
DEACTIVATE TRACKING
Position reporting ceases when DEACTIVATE TRACKING is commanded. The VTU