binary mode

Binary Mode is a mode of operation that deals with non-textual data. When a «binary» parameter is added to a command, it enables every type of data to be transferred or compared rather than just ASCII text.

ASCII is a standard for assigning numerical values to the set of letters in the Roman alphabet and typographic characters. This mode deals with file I/O. It allows programmers to manipulate data files at the byte level rather than at the field level. The sending machine sends each file byte for byte, and the recipient stores the byte stream as it receives it.

Binary mode support has been recommended for all implementations of FTP: