Simplify Communication 
SIM7020 Series_SUB KIT_User Guide         Page    9 / 13 
Here take Putty for example, configure serial port with COM24, 115200bps-8-1-N. 
 
 
Interface  Number  SIM7020 UART  Comments 
Enhanced  COM 24  UART1  Full mode for AT communication 
Standard  COM 23  UART2  No hardware flow control, for FW upgrade 
 
 
4 Firmware Update 
1)  Insert micro USB cable to USB jack (position D) and connect to the PC. 
2)  Open Windows flash tool SIM7020 QDL V1.01 Only for Update as show below. 
 
FW update Tool