Binary files are files that can only run on certain machines or programs.
Good examples of Binary files include shareware software, Microsoft Word files, Microsoft Powerpoint presentations, satellite weather images, and sound files. Unfortunately, there is no universal default transfer mode for FTP clients. This means that unless you tell your FTP client to do otherwise, all of your files will be transferred in the default transfer mode. Fortunately, changing the transfer mode in FTP is easy. There are, of course, always exceptions to this rule.