The Arduino GSM Shield connects your Arduino to the internet using the GPRS wireless network. Just plug this module onto your Arduino board, plug in a SIM card from an operator offering GPRS coverage, and follow a few simple instructions to start controlling your world through the internet. You can also make/receive voice calls and send/receive SMS messages.
This shield is not compatible with Arduino Due. It can be used on Arduino Uno without modification. It also can be used on Arduino Leonardo and Arduino Mega (including ADK) with a slight wire-jumper modification.
The Shield uses an M10 radio modem by Quectel. It is possible to communicate with the board using AT commands. The Arduino GSM library reference page has information and example sketches showing how to use one or more of the functions described. Arduino boards use digital pins 2 and 3 for software serial communication with the M10. Pin 2 is connected to the M10's TX pin, and pin 3 to its RX pin. The modem's PWRKEY pin is connected to Arduino pin 7.
The M10 is a Quad-band GSM/GPRS modem that works at GSM 850MHz, GSM 900MHz, DCS 1800MHz and PCS 1900MHz frequencies. It supports TCP/UDP and HTTP protocols through a GPRS connection. GPRS data downlink and uplink transfer maximum speed is 85.6 kbps.
The board includes Power, Status, and Network Activity LEDs.
This version of the board has a built-in antenna. The board also is available with an SMA connector for attaching your own external antenna.
On-board interfaces The shield comes with a on-board audio jack that can be used for both microphone and line inputs. It is also possible to make voice calls. You don't need to add a speaker and microphone.
There are two small buttons on the shield. The button labeled Reset is tied to the Arduino reset pin. When pressed, it will restart your sketch. The button labeled Power is connected to the modem and will power the modem on and off. For early versions of the shield, it was necessary to press the power button to turn on the modem. Newer versions will turn the modem on automatically. (If you do have an older version that does not turn on automatically, you can solder a jumper to the CTRL/D7 pad on the bottom of the board to make it turn on when you power up your Arduino.)
Several of the modem pins are broken out on the bottom of the board as well.
Powering the shield It is recommended that the board be powered with an external power supply that can provide between 700mA and 1000mA. Powering an Arduino and the GSM shield from a USB connection is not recommended, as USB cannot provide the required current for when the modem is in heavy use, which can reach up to 2A during data transmission. This current is provided through the large orange capacitor on the board's surface.
Included SIM card has limited functionality The shield comes with a SIM card from Telefonica/Movilforum for developing machine-to-machine M2M applications. The SIM card includes a roaming plan, so it can be used on any supported GSM network. See the Availability Guide (note no coverage in Canada). The card can be activated online following instructions included with the shield. The card does not have a PIN by default, but it is possible to set one using the GSM library's GSMPIN class.
However, the included SIM card can be used only to send/receive SMS with other SIMs on the Movilforum network (i.e. other Bluevia/Movilforum SIM cards — common in Europe but almost nonexistent in the U.S.). Also, it can not be used for voice calls or any other functions. To take full advantage of the GSM Shield, you should use your own SIM card that has the support and coverage you need.
Arduino GSM Shield Resources