SIM7100A Module 4G GSM Board

Was poorly packaged and came with bent pins. The board still worked however. It's a rather affordable 4G board but not able to get everything working because the documentation available on the daughter board is not very useful. Voltages suitable etc isn't mentioned anywhere. The only docs available is on the diymall website and shows you how to use the board in debug mode and not using the pins on the board. Fortunately with respect to the AT commands and the ones supported by the SIM7100A module can be found on the SimCom website.

I have this working with a raspberry pi 3. 5v power from the rpi on pins 'supply' & 'gnd'. A 3 second pulse on pin 'pwr' turns it on. Powering the UART side with 3.3v from rpi on pins 'vdd' & 'gnd'. RPI pin 14-TX to Uart pin 'rdx' & rpi pin 15-RX to uart pin 'tdx'. The usb port is set to 9600 baud and the uart is 115200 baud. In python program you must add '\r' at end of each serial write (carriage return) so the command 'ser.write("ATI\r") should get the info from the SIM7100 board.Lots of trial and error to make it all work but can read text messages sent to the GSM module and send text messages from it initiated by the python program.