TCP Connection over GPRS using SIM900 and AT Commands

[jit_singh_tara]

Dear Friends,

I am using sim900 modem to transfer data to a server using at commands .
I am establishing TCP CONNECTION USING at Commands.
The connection does establishes but gets closed automatically after some time...How can i keep it alive indefinitely......

My application:

Need to send data to a remote server via tcp....
First it will attempt to send over gprs , if gprs fails then via sms .

This concept does works but the connection gets closed after some time automatically. Plz suggest where i am missing something.I suppose it has to be keeping the connection alive for indefine time but i dont know which AT command to use for that. Plz help...

I get a close response from the gsm modem after some time after which i am not able to connect with the server until i establish the connection again running all the at commands again....


Please suggest how to proceed...

 

[FvM]

I get a close response from the gsm modem after some time after which i am not able to connect with the server until i establish the connection again running all the at commands again....

What is some time? Seconds, minutes? It's possible that a server closes the connection due to inactivity, even with keep-alive. You may test the server behavior with a PC client, enabling the usage of network tools like Wireshark.