-- my database characterset is al32utf8

  /*----------------------------------------------------------------*/
  /*  CAST_TO_VARCHAR2                                              */
  /*----------------------------------------------------------------*/
  --FUNCTION cast_to_varchar2(r IN RAW) RETURN VARCHAR2;
  --  pragma RESTRICT_REFERENCES(cast_to_varchar2, WNDS, RNDS, WNPS, RNPS);

  --  Cast a raw to a varchar2
  --    This function converts a raw represented using N data bytes
  --    into varchar2 with N data bytes.
  --    NOTE: Once the value is cast to a varchar2, string
  --          operations or server->client communication will assume
  --          that the string is represented using the database's
  --          character set.  "Garbage" results are likely if these
  --          operations are applied to a string that is actually
  --          represented using some other character set.

  --  Input parameters:
  --    r - raw (without leading length field) to be changed to a
  --             varchar2)

  --  Defaults and optional parameters: None

  --  Return value:
  --    varchar2 - containing having the same data as the input raw
  --    null     - if r input parameter was null

  --  Errors:
  --     None
SQL> set serveroutput on
SQL> begin
  2   dbms_output.put_line('Ascii=E0AEA4E0AEAEE0AEBFE0AEB4');
  3   dbms_output.put_line(asciistr(utl_raw.cast_to_varchar2('E0AEA4E0AEAEE0AEBFE0AEB4')));
  4  end;
  5  /
Ascii=E0AEA4E0AEAEE0AEBFE0AEB4
\0BA4\0BAE\0BBF\0BB4

PL/SQL procedure successfully completed.

SQL>

SELECT * FROM nls_database_parameters WHERE parameter like 'NLS%CHARACTERSET';