Welcome to the Wavecom Open AT World
I’ll try to enlighten you…
First of all GPRS is only a bearer service thats quite unusable if you do not use any other protocol on top of it.
The TCP/IP stack from Wavecom is a nice pile of protocols specially written for the OpenAT environment and they are easy to use and work fairly well for basic applications.
It sounds like you do not have basic knowledge about TCP/IP protocols so I suggest you go through a TCP/IP tutorial (there’s alot of stuff like that on the Internet, just google for “TCP/IP Tutorial” )
I also recommend you to play around with the modem and the AT-command controlled TCP/IP stack from Wavecom before you continue with the embedded application in OpenAT.
That will give you understanding about whats going on before a GPRS/TCP/IP application is up-and-running.
One simple application for you to try (to transfer data from one end to another) is to set up a modem (with embedded TCP/IP stack) as a TCP server and to make a connection to it from a PC based client (prefferably a standard Telnet application).
Just make sure that the units allocated IP address is on the same net as your PC (prefferably the IP is dynamically allocated on the Public Internet, its like that with many standard GPRS subscriptions).
But if you have some speciel M2M subscription with static IP and a VPN from your PC, its even better.
After the unit is up-and-running as a listening server, you could try to connect to it from a standard telnet application program on your PC (I’m assuming that your PC has got a connection to the same network as your modem).
//The commands used on the server modem with AT-controlled stack is
AT#APNPW // APN password
AT#APNUN // username
AT#APNSERV // APN server
AT#TCPPORT // TCP port number (must be same on both client and server)
AT#TCPSERV // configure to 255.255.255.255 to accept all incoming requests
AT#CONNECTIONSTART // activate the unit on GPRS network (to get an IP address)
AT#LTCPSTART // to start listening
Now you can use the Telnet program to set up a TCP Socket session to your GPRS modem (to the Port and IP address that your modem has). After the session is active, you can send asynchronous data to/and from the telnet and the modem.
As you might understand, its really important that you know what kind of GPRS subscriptions you are using and that you understand the access the modem have to the packet switched network.
An embedded application in Open AT works the same way except that the application controls the TCP/IP stack via the API instead of a user via AT-commands.
Basically, to do the same stuff as above, but via the API, you need to:
- register on the GPRS network
- then you need to get control of the serial interface dataflow and also the data from the air interface if you want to transfer data between the two interfaces…
Of course you need to take care of every result/callback/event that can occur during the setup but, that you will have read yourself in the documentation
Just keep asking if there’s something more you want to know but avoid posting the same questions in multiple forums
I hope that’ll help more than leaving you even more confused.