User's Manual

DRAFT TrimTrac 1.5 Technical Manual v0.3ab 23
enabled, if the device loses connection to the GSM network while in the QUERY
state, it will not attempt to re-establish connection again until the has cycled back
through the state machine and again re-enters the TRANSMIT or QUERY states.
If the Query Hold Flag is set, then the device will attempt to re-establish
connection to the GSM network if connection to the GSM network was lost prior
to the expiration of the QUERY State Timeout, T5. It will attempt to re-establish
connection to the GSM network until the QUERY State Timeout, T5, has expired.
This may be of benefit to certain applications where no Polling is enabled and the
device may be expected to rapidly come into and exit GSM coverage and there is
a strong need to get messages transmitted as soon as possible. The Automatic
Message Log Dump feature described elsewhere, however, should suffice in most
applications.
Transmit Attempts
The number of transmit attempts is individually selectable for position reports,
status messages and alert messages. Each time the device has messages to be
transmitted, it has enters the TRANSMIT State and assuming a GSM network is
available, it will make the specified number of transmit attempts until the
TRANSMIT Timeout, T3, expires or the message is successfully transmitted,
whichever is earlier.
In the case of normal position and status messages, the default number of transmit
attempts is one, meaning that if the transmission attempt fails prior to expiration
of the TRANSMIT Timeout, T3, either due to an error received from the GSM
protocol stack or loss of GSM network connection, then the device will terminate
the current TRANSMIT state and move on. It will not attempt to re-transmit the
message again in either the current or subsequent TRANSMIT states unless
queried to do so or if Automatic Message Log Dump is enabled.
If the number of transmit attempts is set to some other non-zero valve, then the
device will make however many transmit attempts are specified until the earlier of
confirmation of a successful transmission or expiration of the TRANSMIT
Timeout, T3. If set to “0”, then the device will continuously try to transmit the
message without any transmit attempt limit until the earlier of confirmation of a
successful transmission or expiration of the TRANSMIT Timeout, T3.
In the case of alert messages, the transmit attempts are all set default to 0,
meaning that the device will continue to attempt to transmit alert messages until
the earlier of confirmation of a successful transmission or expiration of the
TRANSMIT Timeout, T3.
In almost all application, the number of transmit attempts should be set either to 0
or 1.