GSM/GPRS SIM900A expansion board uses the SIM900A 4 frequency GSM/GPRS module. Provide GSM/GPRS function extension for Arduino master control board. With this expansion board, Arduino can carry out short message sending and receiving, as well as GPRS data connection communication.
The expansion board can choose the SIM900A serial port or debug SIM900 port connection, if you choose the Debug port, you must use the hardware serial port to control the Arduino simulation serial port is invalid. The board is provided with the Fala capacitor on the module of the RTC power supply.
Debug toggle switch, you can set the sim900A debug port connected to the Arduino or through the Arduino ATMEGA8U2/FT232 connected to a PC, debug debugging3.3V and 5V level compatible, can be adaptive 3.3V or 5V main control board, support maple leaf and Chipkit 3.3V this kind of other platform development board. After the SIM900A Arduino board is plugged in, it must provide the DC 9V/2A power supply, otherwise it may not work properly . Four frequency 850/900/1800/1900MHz GSM/GPRS (support for China Unicom, mobile 2G card, do not support Telecom Card)