Getting Started

Inserting the SIM card

Get a Nano-SIM card and insert it into the boards push-push type SIM card slot.
Power should not be connected to the device during SIM card insertion

Powering the device

This board can run from any of the two power sources,
Main Power Input
[VCHG DC Jack connector]
  • Can take 12V to 42V DC [Connect to 12V Lead Acid Battery]
  • Its a DC Jack type connector
Has Reverse Polarity Protection
Battery Input
[VBAT connector J41]
  • Can take 3.7V to 4.2V DC [Connect a single cell 3.7V-4.2V Li-Po or Li-Ion Battery]
  • Use at least 400mAH and above capacity batteries
  • Its a JST-XH type connector
Doesn't have Reverse Polarity Protection
Device can start functioning with any of above power sources.

Turning ON the modem :

You need to press the PWRKEY switch for at least 1 second to boot the module. If you are using the PWRKEY header pin connected to MCU. There is a transistor between your header pin and the modules PWRKEY pin. So, you can boot the module from MCU by sending a high pulse on the PWRKEY pin for at least 1 second.
PWRKEY and RESET header pins are routed through a NPN transistor so you need to send HIGH pulses to activate the modules respective pins

LED Indicators

  • Once the device is powered ON, The Power LED D18 will turn ON.
  • Once the module is booted using the PWRKEY button or PWRKEY header pin GSM_STATUS LED D17 will turn ON indicating the module has booted.
  • Once the SIM is registered to the network, the NETLIGHT LED D6 starts blinking otherwise its stable.
  • POWER LED remains ON all the time


USB Interface : You can use USB interface for sending AT commands and updating the modules firmware. Make sure you install the drivers for the module before connecting USB. Drivers can be downloaded from the store website where you purchased the module.
UART Interface :
You can also use the UART interface to send AT commands to the module. The default baud rate is 115200. The modules IO levels are 1.8V so there is a onboard TXS0104 or TXS0102 level translator which translates the modules UART TXD, RXD, DTR, RI lines 1.8V IO levels to MCU IO levels. For level translator to function properly you need to connect the VTRANS pin to the MCU IO level voltage, either 3.3V or 5V.
All remaining module pins except UART TXD, RXD, DTR, RI, PWRKEY, RESET exposed on headers are at 1.8V levels, so care must be taken when interfacing these lines to external hardware like MCU. Use appropriate IO level translation wherever needed.