TECHNICAL MANUAL
Telit GM862-GPS
Quad Band GPS Data Terminal Module
Pag.25 of 79
Rev. 0
3.10.7 Close the Socket and deactivate the context
The connection can be closed because of:
- remote host TCP connection close
- socket inactivity timeout
- Terminal Equipment by issuing the escape sequence "+++"
- Network
deactivation
Note: if in the raw data to be sent there's an escape sequence, then the TE must work it
out and sent it in a different fashion to guarantee that the connection is not closed.
The pause time is defined in the parameter S12.
On the reception of an escape sequence the GM862-GPS closes the connection,
deactivates the GPRS context returning to command mode and issuing the NO CARRIER
code.
3.10.8 Enhanced Easy GPRS Outgoing connection
The New Enhanced Easy GPRS feature provides a way to place outgoing TCP/UDP
connections and keep the same IP address after a connection, leaving the GPRS context
active.
The steps that will be required open a socket and close it without closing the GRPS
context are:
g) configuring the GPRS Access
h) configuring the embedded TCP/IP stack behaviour
i) defining the Internet Peer to be contacted
j) request the GPRS context to be activated
k) request the socket connection to be opened
l) exchange
data
m) close the TCP connection while keeping the GPRS active
All these steps are achieved through AT commands.
As for common modem interface, two logical status are involved: command mode and
data traffic mode.
- In Command Mode (CM), some AT commands are provided to configure the Data
Module Internet stack and to start up the data traffic.
- In data traffic mode (Socket Mode, SKTM), the client can send/receive a raw data
stream which will be encapsulated in the previously configured TCP / IP packets which
will be sent to the other side of the network and viceversa. Control plane of ongoing
socket connection is deployed internally to the module.
3.10.8.1
Configuring the GPRS access
The GPRS access configuration is done by setting:
- the GPRS context number 1 parameters (see +CGDCONT command)
- the Authentication parameters: User Name and Password (see commands #USERID,
#PASSW)
3.10.8.2
Configuring the embedded TCP/IP stack
The TCP/IP stack behaviour must be configured by setting:
- the packetizer default packet size (see command #PKTSZ)
- the data sending timeout (see command #DSTO)