This Directly Derived Data Type is defined by the following XML fragment:

<DataType Name="USTRING" Comment="A WSTRING with UTF-8 serial encoding and decoding" >
  <ASN1Tag Class="PRIVATE" Number="1" />
  <DirectlyDerivedType BaseType="WSTRING" />
</DataType>

Its implementation in the FBDK is the same as that of the WSTRING type, with the exception that its encoding for byte-serial transmission differs from that given for WSTRING in subclause 5.4.4.2 of the Compliance Profile for Feasibility Demonstrations:

• Its Type field is encoded as the ASN.1 [PRIVATE 1] tag, that is, C1 in hexadecimal notation.
• Its Value field contains the UTF-8 encoded value of the encapsulated Java™ String. This widely-used encoding is as efficient as that of the STRING type for characters in the 7-bit US-ASCII code set, while retaining the ability to encode 8-bit characters and multi-byte code sets.