//***********************************************************************************************************************************
        // ForcedASCII  we'll never allow Unicode that does not match to ASCII
        // see https://www.cl.cam.ac.uk/~mgk25/ucs/examples/quickbrown.txt for sample text to test
        //***********************************************************************************************************************************
        private string ForcedASCII(string fromString)
        {
            string res = "";
            try
            {
                Byte[] bytes;
                Char[] chars = { ' ' };
                bytes = (new System.Text.ASCIIEncoding()).GetBytes(fromString);
                Array.Resize(ref chars, bytes.Length);
                int ct = (new System.Text.ASCIIEncoding()).GetChars(bytes, 0, bytes.Length, chars, 0);
                res = (new String(chars, 0, bytes.Length)).ToString();
            }
            catch (Exception)
            {
                res = "";
            }
            return res;
        }

        //***********************************************************************************************************************************
        // ValidASCII - return true if str is a valid 8-bit ASCII string
        //***********************************************************************************************************************************
        private bool ValidASCII(string str)
        {
            return (str == ForcedASCII(str));
        }