User's Manual

DRAFT TrimTrac 1.5 Technical Manual v0.3ab 76
Position Age
Medium Priority
Alert (MPA) Flag
“1=Aged” “0=Current”
“0=Normal” Normal Operation
“1=Activated”
Upon initiation of a MPA, the
MPA Status flag is set “1=Activated” and the
device terminates its current operation immediately, unless in the TRANSMIT state,
and transitions to STATUS state. If in the TRANSMIT state, then the current
TRANSMIT state is completed prior to transitioning to the STATUS state. While in
the STATUS state, the devices generates a new STATUS_MESSAGE in which the
TriggerType is set “2=Alert”. This STATUS_MESSAGE is combined with most
recent logged POSITION_REPORT, collectively “MPA Report”. Then the device
transitions to the TRANSMIT state and sequences as follows:
a) If the GSM protocol stack confirms that the MPA Report was successfully
sent to the GSM network, then the
MPA Status flag is changed from
“1=Activated” to “2=Sent” and the unit will transition to the QUERY state;
OR
b) The device will make MPA Transmit Attempts, N6, prior to the expiration
of the MPA Transmit Timeout, T16. A new transmit attempt will be
initiated each time the GSM protocol stack confirms the attempted
transmission failed or if connection to the GSM is lost. Upon termination
of the current TRANSMIT state, the device will transition to the DELAY
state; OR
c) If a connection to a GSM network has not been established prior to
expiration of MPA Transmit Timeout, T16, then the current TRANSMIT
state will be terminated and transition to the DELAY State.
“2=Sent”
Regardless of motion, cycle continuously
through FIX, STATUS, TRANSMIT(T16),
QUERY(T5) and DELAY(T14) states until:
a) The GSM protocol stack confirms a
MPA Report containing a new position
fix is successfully sent; OR
b) A sequence altering message command
is received during the QUERY state.
Operate in accordance with the
standard State machine;
provided, however, MPA Idle
Timeout, T12, and MPA Delay
Timeout, T14, shall apply unless
otherwise instructed by the
server application.
“3=Acknowledged”
Table 18, Medium Priority Alert Processing