I am developing an application that sends a USSD message to a USSD gateway. However, I do not have an account for the carrier owner of the gateway yet. Still, I have some other accounts and I would like to test if my USSD codding is fine.
In that sense, is there a standard USSD command I can send and be understandable and answered by any USSD gateway regardless of the operator? If so, which one(s)?
As you probably know, USSD stands for Unstructured Supplementary Services Data, and the structure of the messages is defined by individual operators.
A quick glance at the 3GPP protocol test spec 34.123 part 1 shows no protocol tests with standard USSD strings either.
Allowed formats for USSD messages are defined in 3GPP TS 22.090. Therefore, if you find out some USSD dialogues that are valid with the operators with which you do have an account, you can test how your code works with the allowed USSD message formats (instead of particular strings).
You can also try these common call diverting messages.
来源：https://stackoverflow.com/questions/17405151/is-there-a-standard-ussd-string-i-can-use-to-test-a-random-ussd-gateway