I did in fact install the Open Client and ODBC drivers for Sybase 12.0. Is this what you mean?
Plus I was able to connect to this database from the same windows machine using some db client software. As for an interfaces file, I don't really know about that, although I did have to make an entry into the file: C:\sybase\ini\sql.ini to get the client software to work. So yes, I can logon to the database.