For Windows, you could set the EC200T to rndis mode with the AT command
AT+QCFG="usbnet",3
It will take effect after reboot.
Please use the AT command to check the network registration.
AT+CGDCONT?
AT+CEREG?
AT+COPS?
AT+CGREG?
AT+QENG=“servingcell”
If it is already registerred, you need to set up data connection with AT command
AT+QNETDEVCTL=1,1,1