At+cusd=1,"#123#",15 mt300n v2

I’m trying to use AT commands from the GUI to do some basic stuff like check prepaid balance using the command above. #123# is the code I would enter on a phone to do it. I just get an “UNKNOWN” error,

Modem is a Huawei E3276S

Any ideas?

Would like to help but if you use external modem, you need to consult the modem instructions.

Our GUI only support Quectel modems.

I don’t think there is GUI for Huawei modem, right?