The GPRS Shield is based on SIM900 module from SIMCOM and compatible with Arduino and its clones. The GPRS Shield provides you a way to communicate using the GSM cell phone network. The shield allows you to achieve SMS, MMS, GPRS and Audio via UART by sending AT commands (GSM 07.07 , 07.05 and SIMCOM enhanced AT Commands). The shield also has the 12 GPIOs, 2 PWMs and an ADC of the SIM900 module(They are all 2V8 logic) present onboard. Features Quad-Band 850 / 900/ 1800 / 1900 MHz - would work on GSM networks in all countries across the world. GPRS multi-slot class 10/8 GPRS mobile station class B Compliant to GSM phase 2/2+ Class 4 (2 W @ 850 / 900 MHz) Class 1 (1 W @ 1800 / 1900MHz) Control via 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). Embedded TCP/UDP stack - allows you to upload data to a web server. RTC supported. Selectable serial port. Speaker and Headphone jacks Low power consumption - 1.5mA(sleep mode). Industrial Temperature Range - -40°C to +85 °C