Install dependencies:
$ sudo apt install minicom libqmi-utils
Set up modem by minicom, set /dev/ttyUSB2 115200:
$ sudo minicom -s
After setup, you will be able to use AT commands: Quectel_RG50xQ&RM5xxQ_Series_AT_Commands_Manual_V1.1.1_Preliminary_20201009.pdf.
Let's check the firmware by:
at+qgmr
# output:
# RM500QGLABR11A06M4G_01.001.01.001
# OK