This is a shield for the CC3000 WiFi Module. The CC3000 from TI (Texas Instruments) is a self-contained wireless network processor that makes incorporating internet connectivity into your project simple. Instead of the more standard UART communication method, the CC3000 module utilizes an SPI interface allowing you, the user, to control the flow of data...
The GPRS/GSM Shield provides you a way to use the GSM cell phone network to receive data from a remote location. The shield allows you to achieve this via any of the three methods:
Short Message Service
IComsat is a GSM/GPRS shield for 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), and fully compatible with Arduino / Iteaduino and Mega.