SIM900 GSM GPRS Shield

Features

Here’s some of the most important features of the shield:

• Compatible with Arduino and clones
• Based on SIM900 module from SIMCOM
• Allows you to send SMS, MMS, GPRS and Audio via UART using AT commands.
• It has 12 GPIOs, 2 PWMs and buit-in ADC of the SIM900 module
• Quad Band: 850; 900; 1800 and 1900 MHZ, so it should work in all countries with GSM (2G) networks
• Control via AT commands
• Supports RTC (real time clock) – it has a holder for a 3V CR1220 battery at the back 

Guide to SIM900 GSM GPRS Shield with Arduino.