Specifications

GT300 @Track Air Interface Protocol
- 35 -
4. Develop User Guide
4.1. Register
4.1.1. Connection Mode
The @Tracker Air Interface supports SMS and GPRS data communication via the GSM network
and can be configured to use one or the other exclusively or automatically switch between the two
by the parameter <report mode> of AT+GTSRI.
If GPRS is enabled via the appropriate report mode setting, then the GPRS connection parameters
are used to establish GPRS sessions. The @Track Protocol supports both TCP and UDP transport
protocols.
The following lists the detail settings of <report mode>.
— TCP Short Connection + SMS
In this mode, the terminal uses the TCP short connection as the default mode and uses SMS
as the backup. When there is data need to be sent, the terminal will establish a short
connection to the backend server via TCP protocol and send the data. If fail to send the data,
it will then send the same data via SMS again.
— TCP Short Connection
In this mode, the terminal connects to the backend server via TCP protocol each time it needs
to send data and shuts down the connection after the data transmission.
— TCP Long Connection
In this mode, the terminal connects to the backend server via TCP protocol after it powers on,
then keeps the connection alive and uses it all the time unless the connection is broken. If
the connection is broken, the terminal will try to connect to the backend server again and
maintain the new connection.
To maintain the connection, the terminal sends heart beat data to the backend server
periodically and the backend server responds to each of the heart beat data. In this way,
both sides can confirm the connection is alive.
This is the only mode that the backend server could send commands to the terminal via TCP
connection. In other words, the backend server can send commands to the terminal either
via SMS or via TCP connection in the TCP long connection mode.
— UDP Mode
In this mode, the terminal sends data to the backend server via UDP protocol.