How to use USSSD for NTT DOCOMO JP

IoT Modules LTE Standard Module
1

My firmware is EC20CEHCLG. Provider is NTT DOCOMO (Japan)

When I try USSD by command:

AT+CUSD=1,“*111#”,15;
OK

+CME ERROR: 258

What should I do?

2

Why is there a semi-colon in the AT command?

Are you sure the double quotes are ASCII characters, and not other unicode versions?

3

I tried command

AT+CUSD=1,“*111#” // no semi-colon

And CUSD with PDU mode. But I still get CME ERROR 258

4

I’m sorry, but I don’t have a decode for +CME ERROR: 258

So I don’t know what sort of error is being reported.