4 Cross phase compatibility

04.903GPPTSUnstructured Supplementary Service Data (USSD)

For the mobile initiated USSD operations, a number of changes exist between the present document and the protocol version 1 specification. For these operations the main body of the present document assumes that all network entities comply with this version of the service. In this case an additional subclause defines the additional requirements for when one or more network entities or the Mobile Station (MS) complies with the protocol version 1 specifications for the USSD operations.