0 No further user action required (network initiated US SD-Notify, or no further
information needed after mobile Initiated operation).
1 Further user action required (network initiated USSD-Request, or further
information needed after mobile initiated operation).
2 USSD terminated by network. the reason for the termination is indicated by the
index, as described in CUSD Termination Cause Table Index.
3 Other local client has responded.
4 Operation not supported.
5 Network timed out.