It's called USSD, there's a short list on Wikipedia. A lot of them are carrier dependant, and some carrier models of certain handsets will block some codes. ht

It's called USSD, there's a short list on Wikipedia. A lot of them are carrier dependant, and some carrier models of certain handsets will block some codes. https://en.wikipedia.org/wiki/Unstructured_Supplementary_Service_Data https://en.wikipedia.org/wiki/Unstructured_Supplementary_Ser...