User's Manual

DRAFT TrimTrac 1.5 Technical Manual v0.3ab 44
In general, testing done to date indicates that a unit located in the glove box will
on average get approximately 50% fewer position fixes than a unit located on the
dashboard of the vehicle. Units placed under the front seat will performance
about the same as units placed in the glove box unless the seat is a power seat.
Power seats have considerably more metal than manually adjusted seats and the
added metal attenuates the GPS signal that much more. It is not recommended
that units be placed in the trunk of standard 3-box style sedans unless an optional
external GPS antenna is used.
GSM Jamming
The TrimTrac 1.5, or the optional external GPS antenna, should be installed as far
away as possible from other transmitting antennas including other TrimTrac 1.5s,
satellite communication, radar, and VHF radio. These transmitters may emit
jamming signals that interfere with the GSM phone’s ability to track the GSM
signal. If there are other transmitting antennas located on the vehicle, try moving
the TrimTrac 1.5 farther away from these antennas. Generally, the stronger the
other transmitting device, the wider the distance required between antennas.
No Data Communication with Base
If the TrimTrac 1.5 is not communicating with the server application as expected,
do the following:
1. Confirm that a data-enabled SIM (SMS or GPRS) is inserted in the
unit and that the hold down latch is pressed all the way down and
securely holding the SIM card at all four corners.
2. Confirm proper provisioning, including Unit ID, SMS Destination
Address, Security Password, and, if needed, SIM PIN;
3. Verify that the unit has its application parameters configured as
desired. Pay particular attention to the Report Delay Flag, QUERY
Timeout, T5, and TRANSMIT Timeout, T3, settings. Default settings
for QUERY Timeout, T5, and TRANSMIT Timeout, T3, are
recommended.
4. Set the Diagnostics Mode to “1=Enabled” and observe the LED to
confirm that the unit properly enters the TRANSMIT and QUERY
states.
5. Use the AT+CTKO? command with a provisioning module to review
logged messages while paying particular attention to the GSM Status
field.
Base Modem Configuration
Consult your modem manual for configuration instructions. Each modem
manufacturer has its own settings and control commands. Verify that your
configuration, PIN numbers, and so on, are correct.