SIM808 GSM/GPRS/GPS 3G Shield

• Model Number:23052
• Type:RF/Wireless Development Boards and Kits
• Place of Origin:China
• Certification 1:ROHS
• Certification 2:CE

"SIM808 GSM / GPRS / GPS 3G Shield

Three power input interface: DC044 interface and V_IN and lithium battery interface.
Switch: Used to turn on / off the module's input power. When using, please confirm the toggle switch to OPEN state (near the inside of the circuit board).
SMA antenna interface: There is a GSM antenna interface, a GPS antenna interface and a BT antenna interface.
Start Button: The LED (PWR) will light when the circuit board is powered on. When the button is pressed (approx. 2 seconds), the other three LEDs will light and one of the LEDs will flash; this means that the SIM808 is now operational. When the power, GSM and GPS antennas, and the SIM card are properly connected to the module, the LED will flash slowly (1 second for 3 seconds) to indicate that the module is registered to the network and you can make a call or do other things.
A TTL level interface. Note: The pins of the VMCU are used to control the high level TTL UART to match the 1.25V / 3.3V / 5V system. If you want to use 51 MCU to control this VMCU pin should be connected to DC5V. If using an STM32 MCU, the VMCU pins should be connected to DC3.3V. The RXD pin is the RXD of the SIM808 and the TXD pin is the TXD of the SIM808. The pin of V_IN can be connected to the power supply. This pin has the same function as the DC044."