Unicode provides a method of encoding national characters and symbols using more than the 8 bit character sets originally supported by ODBC, which limited character data to a maximum of 256 different characters.
Although many systems exist to extend this limit via translator libraries and through the use of "Code Pages", none of these are sufficient for character sets with more than 256 individual symbols or for applications needing to access different sets of national characters concurrently. There are various methods of doing this and ODBC and InterBase/Firebird use two slightly different forms.
ODBC has provided "Wide" data types for some time, but until ODBC 3.51 there was no consistent Unicode interface. A Unicode ODBC driver enables all string input and output to be presented in Unicode, so not only can data be returned from a database in Unicode, but SQL queries may also be executed in Unicode.
Whilst the ODBC version of Unicode provides for 16 bits per symbol, InterBase/Firebird uses a more advanced encoding method called UTF8, where the length of individual symbols may vary from 8 to 32 bits. Typically a InterBase/Firebird database will be created using a extended character set, UNICODE_FSS being the full Unicode set.
The Easysoft driver transparently converts between these two forms, enabling Unicode ready applications (such as Microsoft Access) to display and modify Unicode data in InterBase/Firebird databases. It can be said to be a Unicode ODBC driver.