Hello,
I have a SeeedStudio GPRS module, which uses a SIM900 card. I have successfully gotten it to send messages, but now I need to get it to receive them. How can I do that? What AT commands do I need to use?
This page has what you're looking for:
http://www.cooking-hacks.com/index.php/documentation/tutorials/raspberry-pi-gprs-gsm-quadband-sim900