The GSM / GPRS (General Packet Radio Service) Shield is a new nonvoice value added service that delivers GSM/GPRS 850/900/1800/1900MHz performance for voice, SMS, Data, and Fax in a small form factor and with low power consumption. It is controlled via AT commands (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands), and fully compatible with Iteaduino/Arduino and Mega. Features: *Onboard GTM900 - B double-frequency 900/1800 MHZ highly integrated GSM/GPRS module *Onboard LM2596 high-power power supply chip, powerful guarantee module work stably for a long time *The on-board flip SIM gets stuck, easy loading and unloading of SIM card *The on-board terminals or DC power supply (the default terminal), 7.5-12 v input voltage *The onboard audio interface and microphones, convenient user calls tests *Onboard UART interface, meet different user requirements *Onboard three LED lights: power light, signal lights, calls for *PCB board size: 68.5 (mm) x38.5 (mm)