Specifications

Telit GM862-PCS/-GPRS/-GSM Product Description

1vv0300604, Rev. ISSUE#14 - 22/01/04

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.

6.9.2.1 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)

6.9.2.2 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)

- the socket inactivity timeout (see command #SKTTO)

6.9.2.3 Defining the Internet peer to be contacted

As last setting definition, the host to be contacted and on which port/protocol must be set :

- the socket definition (see command #SKTSET)

This command permits also to specify the host name instead of its IP address, if a host name is

given to the set command, then the module stores it as a host nick name. It is care of the module

user to guarantee that the host nick name provided corresponds to an existing internet peer.

If an host nick name has been given then, while opening the connection in response to the

AT#SKTOP command, the module will autonomously activate a GPRS connection and query its

DNS to obtain the IP address relative to the host nick name provided. This process of context

activation and DNS query may require a bit more time and requires that the GPRS network

coverage is good enough to permit data transfers.

6.9.2.4 Open the connection with the internet host

With the AT#SKTOP all the process required to connect with the internet host starts:

- GM862-GPRS activates the first context

- GM862-GPRS proceeds to the authentication with the parameters specified on par. 6.9.2.1

- Eventually does the DNS query to resolve the IP address of the host name internet peer