Reference: RBD-0443
GPRS GSM SIM900 Arduino Shield
Based on SIMCom‘s SIM900 Module Quad-Band 850 / 900/ 1800 / 1900 MHz - would work on GSM networks in all countries across the world. Control by AT commands - Standard Commands: GSM 07.07 & 07.05 | Enhanced Commands: SIMCOM AT Commands. Short Message Service - so that you can send small amounts of data over the network (ASCII or raw hexadecimal).