This module is a GSM/GPRS shield for the Arduino and based on the SIM900 Quad-band GSM/GPRS module. It is controlled via AT commands (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands).  This shield has been tested successfully in Costa Rica to work with the ICE, Claro and Movistar using the Arduino library below.

This shield comes with an antenna and extension interface cable.

The module can be powered on and off via software control.

3.5mm sockets for microphone and earphone interface.

Features:

Quad-Band 850/ 900/ 1800/ 1900 MHz
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 (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands)
Low power consumption: 1.5mA(sleep mode)
Operation temperature: -40°C to +85 °C

Arduino Library

Schematic

Datasheet

SIM900 AT Command Manual