Справочник Пользователя для Telit Wireless Solutions Easy GPRS

Easy GPRS User Guide

80000ST10028 Rev. 0 - 02/01/07

page 17 of 35

2.1.1 Easy GPRS Outgoing connection

The 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 required to open a socket and close it without closing the GRPS context are:

• configuring the GPRS Access

• configuring the embedded TCP/IP stack behaviour

• defining the Internet Peer to be contacted

• request the GPRS context to be activated

• request the socket connection to be opened

• exchange data

• close the TCP connection while keeping the GPRS active

All these steps are achieved through AT commands. As for common modem interface, two logical
statuses 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 vice versa. Control plane of ongoing socket connection is deployed
internally to the module.

2.1.1.1 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)

2.1.1.2 Configuring the embedded TCP/IP stack

The TCP/IP stack behaviour must be configured by setting:

• the packet default size (see command #PKTSZ)
• the data sending timeout (see command #DSTO)

• the socket inactivity timeout (see command #SKTTO)

2.1.1.3 Saving settings for the Internet peer to be contacted

In order to maintain all settings for TCP/IP stack refer to the AT command #SKTSAV that saves the
actual socket parameters in the NVM of the device.