GPRS Shield - EFCom is an ultra compact and reliable wireless module. This GPRS Shield is compatible with all boards which have the same form factor (and pinout) as a standard Arduino Board. EFCom is base on SIM900 4 Frequency GPRS module.
The GPRS Shield is configured and controlled via its UART using simple AT commands. Just plug this shield on the Arduino/ Freaduino board, you could easily use AT command to control EFCom Shild. You can use the 2 jumper blocks to connect the SIM900 URAT post to any pins within D0-D3(for Hardware/Software serial port). There is a switch on board , you can use it to select the connection of the UART port or Debug port , even be set on on Arduino, but by the switch and jumper block, the SIM900 can be connected to PC via FT233RL.