6
2 Functions
2.1 Device initialization
After host powers up, four indicators will fully light for 1 second, then fully turn off. Later,
terminal starts to initialization process.
If GPS module works well, after GPS has valid positioning, "GPS indicator" will start
blinking.
Meanwhile, GSM initialization begins. If initialization is successful, "GSM indicator" lights,
then dial to centre server. After a successful connection, "GSM indicator" starts blinking.
When GSM initialization finished, system will run Iridium module's initialization. If
successful, "Iridium network" indicator starts blinking.
2.2 Parameter settings
Device should set parameters before use. You can set parameters through setting tool via
device's RS232 standard serial port which also has data t
ransparent transmission
function.
Detailed setting commands see "User Communication Protocol" part in Auxiliary
《
SAT802
Communication Protocol.pdf
》
.
2.3 Working mechanism of data transparent transmission
Any data not being above-mentioned parameter format that terminal serial port received will
be considered as "user transparent transmission data", and according to channel status, data
will be sent to its destination by GPRS data link or Iridium SBD.
Bytes interval in the data packet of "user transparent transmission data" should not be larger
than 0.5 second and the length of each data packet should not be larger than 336 bytes. When
large amounts of data need to be transmitted, data will be divided into packets.
Data transmission between terminals has a data length limit with a maximum of 266 bytes.
As a response, after sending "user transparent transmission data", device then sends a "SEND
OK" message to external data device via serial port. After external data device receives this
response, it prepares to send next data packet.
In dual-mode communication, GPRS channel has priority. If condition meets < login failed or
heartbeat confirmation failed, reboot GPRS link connection, if failed, wait 30 seconds, then
again, if still failed after three times>, it will automatically switch to Iridium SBD
communication channel. In Iridium SBD communication channel mode, system still keep
booting GPRS link connection until connecting successfully, if connected, communication
mode turns to GPRS communication channel.
