public static String to_ascii(String str)
    {
        final String letters="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        String result="";
        int len=str.length();
        for(int i=0;i<len;i++) {
            int c = (int)str.charAt(i);
            if (c>0 && c<127) result+=str.charAt(i); else {
                boolean found=false;
                for (int lan=0;lan<MAXLANS;lan++) {
                    for (int j=0;asc2lan[lan][j]>=0;j++) {
                        if (c==asc2lan[lan][j]) {
                            result+=letters.charAt(j);
                            found=true;
                            break;
                        }
                    }
                    if (found) break;
                }
                if (!found) result+="?";
            }
        }
        return result;
    }