AT Commands for GPRS

[ic007023]

Dear All,



This email is little generic & basic as far as GPRS communication is concerned.



I have a doubt regarding the AT commands for GPRS communication.



Typically, for GPRS communication, the AT commands are issued to the GPRS modem in following steps:



-----------------------------------------------------------------------------------------------------------



STEP 1: Context Parameter Settings



AT+CGDCONT = 1, "IP","apn.airtelgprs.com","0.0.0.0",0,0 <CR>



STEP 2: Setting Minimum Quality of Service required



AT + CGQMIN = 1, 0, 0, 0, 0, 0 <CR>



STEP 3: Setting Required Quality of Connection on context activation



AT+CGREQ=1,1,0,0,0,31 <CR>



STEP 4: GPRS Context activation & Entering data state



ATD*99***1#<CR>



STEP 5: Start sending data over GPRS connection

ABHISHEK IS SENDING DATA OVER GPRS <CR>



STEP 6: Toggle between Command Mode/Data Mode

+++



STEP 7: Terminate the GPRS connection

ATH



----------------------------------------------------------------------------------------



Doubt: If on the receiving side, I have a PC with fixed global static IP Address and an application running on a port, In above set of AT commands, I have not specified the receiver's IP address and Port on which the application is waiting to receive GPRS data packets. So how will the data packets get routed to my PC? Have I missed some command or am I wrong some where?



Please clarify. It has been quite a while, when I am looking for answer to above question. I am sure some body can help me on this.


Abhishek

[petrib]

If you have a fixed IP address for your PC for the PC's network connections, it is irrelevant.

Your GPRS modem will get its IP address from the cellular network operator (carrier, if you wish) whose SIM card you are using. Usually it is not a public IP address (no-routable) and cannot be reached directly from the Internet. Even if the operator provides a public IP address, it'll still be dynamically assigned, and it is not reachable (nobody on the Internet can initiate a connection to it).

If you want to receive "unsolicited" data in your PC, connected to a cellular network with a GPRS modem, you will need to set up an intermediate server (that has a fixed Internet connection) that your PC connects to, and listens for data from that server (which is also the server that those whose data you want connect to as well).