How to use binary or ASCII mode

Files and data can be transferred in two different modes with all client classes - binary mode and ASCII mode. The transfer mode should always be set explicitly to ensure the correct mode is used.


ASCII mode should be used when end-of-line character translation is required. When using ASCII mode, files are not transferred byte-for-byte. Instead, the newline character(s) on the source platform (e.g. in Windows, CR+LF) are replaced with the newline character(s) on the target platform (e.g. on Unix, LF). This means the source file may not be the same size as the end result if the platforms differ. If binary mode is used, for example, to transfer Unix text files to a Windows platform, many Windows text editors will not recognize the Unix newline characters, and the file will be difficult to read. To use ASCII mode, the setType() method should be used, supplying the ASCII type as shown.


ASCII mode is the default for the majority of FTP servers and is therefore also the default in edtFTPj/PRO.

It's important to note that it is often acceptable to transfer text files in binary mode since most modern text editors are able to deal with UNIX and Windows end-of-line characters interchangably. Furthermore, text files that appear to be ASCII files often contain "extended ASCII" characters which may be incompatible between different platforms.  It is therefore advisable to use binary mode unless end-of-line character translation is definitely required.

Binary Mode

Binary mode (a.k.a. image mode) should be used whenever no end-of-line translation is required. In binary mode, the file is transferred byte-for-byte, i.e. an exact copy of the file or data is transferred. Typically, binary mode is used for files such as executables, compressed files, media files and non-text document formats such as OpenOffice or Microsoft Office files. To use binary mode, the setType() method should be used, supplying the BINARY type as shown.