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Text file transmission using SIM300 GPRS modem

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sandeep polasa

Newbie level 6
Nov 20, 2009
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Hi. I am working on communicating with two SIM300 GPRS modems. I am able to establish the TCP/IP connection using GPRS. I also sent a text data from one GPRS modem to another using TCP/IP. I configured the second GPRS modem as the server. Now i need to send a text file from one GPRS modem to another.

Please help me if anyone know the procedure to transfer a text file from one GPRS modem to another using TCP/IP?

Two comments:
- You should refer to SIMCOM TCP/IP application note and AT command manuals for the commands to utilize the embedded TCP/IP stack.
- Mobile phone service providers usually restrict routing of inbound connections to particular TCP ports or block it completely. You have to check, if server operation is possible with your mobile internet provider.

FvM is correct in saying TCP/IP communication between modems is difficult unless you can make arrangements with the provider, e.g. modems are usually on private networks behind NAT boxes making inbound TCP connections difficult. In a similar application I had two modems making TCP connections to a server with a static IP address. One modem left data on the server, the other collected it. If timing is critical when the first has sent the data it could send an SMS message to the second modem to make a connection collect it.

I have interfaced gsm modem to atmega 16 to send gps data to a mobile number. Now, i am finding difficulty in sending it to a static ip. I am using a vodafone gprs activated connection. I am sure that i can handle the coding part but i am finding difficulty with the PDP context and APN. Can you please help that from where can i get such information or just the parameters of "AT+CGDCONT" and "AT+CDNSCFG" command's
Thanking You

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