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SIM900 GSM/GPRS TTL UART Modem - User Manual
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Page 15
INTERFACING THE GSM MODEM
Interfacing the Modem to microcontroller (Basic connection)
Fig:3 GSM Modem Interfacing with Microcontroller (Basic Connections)
The Modem can be directly interface with 5V microcontrollers like PIC ,AVR , 8051 Derivatives , Arduinos and 3V3 Microcontrollers
like ARM ,ARM Cortex XX ect. Make ensure V_INTERFACE pin is supplied with same voltage level as the microcontroller VCC. As
per the Fig:3 there is only 2 connections are required to use the modem . Connect RX pin of the modem to the TX pin of the
microcontroller and TX pin of the modem to microcontroller’s RX pin. The connected power supply (4.2v to 12v dc) should be capable
of handling current up to 1 A .
