The ACEduino GSM/GPRS Shield is a communication system using the GSM/GPRS cell phone network. It utilizes an Arduino-board compatible SIM900 module and uses standard AT commands for communication via UART.

Features:

Quad-Band 850 / 900/ 1800 / 1900 MHz A guarantee that it
can work in all GSM networks in all countries.
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.
Speaker and Headphone ports used for phone calls
Low power consumption:1.5mA (sleep mode)
UART pins are selectable through ACEduino
Digital Input/Output pins 0 to 6.