Overview | Adafruit FONA 808 Cellular + GPS Shield for Arduino | Adafruit Learning System
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Basics: Project 053d SIM808 GSM GPRS GPS Bluetooth evolution board (EVB-V3.2) at Acoptex.com / ACOPTEX.COM
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Sim808 - Arduino connection - General Electronics - Arduino Forum
SIM808 GSM GPRS GPS BT Development Board Module for Arduino - products that work with official Arduino boards