Geeetech updated GPRS/GSM SIM900 Shield V2.0 board arduino compatible Compatible with standard Arduino and Arduino Mega. Selectable interface between hardware serial port and software serial port. ou can use your Arduino to dial a phone number or send a text to your friend via easy to use AT commands now. This new version features a quad-band low power consumption GSM/GPRS module SIM900 as well as a compact PCB antenna. Improvements on interfaces and basic circuit have been taken to make it more concise and reliable.