SIM808 GSM GPRS Module GPS Devolpment Board + Antenne Dual Band 900/1800 MHz

TTL serial interface: a TTL level interface. And if use the STM32 MCU, the pin of VMCU should be connected the DC3.3V. The pins of RXD is the RXD of SIM808 and the pins of TXD is the TXD of SIM808.

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