Binary Files are transferred as a binary stream of data. The data is transferred as is without any transformations.
ASCII The transferred data is considered to be ASCII encoded. This transfer type is necessary because different systems have different data storage representations. For example Unix systems typically represent line ending with a single LF character. So when data is received by a Unix system, the CR LF line endings will be transformed to LF line endings before the data is stored. The transformation is done in reverse (LF -> CR LF) before the data is sent from a Unix system to the receiving host.
Auto Files are transferred in binary mode unless they match an entry in the ASCII File List.
ASCII vs. Binary
There are very few corner cases in which files must be transferred in ASCII mode. Generally transfer all files (even text files) in Binary mode which is the default setting.
How To change the setting
Connect to the remote server
Select the Tools tab
Click on Favorite Properties
In the Favorite Properties dialog go to the Transfer - ASCII / Binary dialog.
To transfer specific file types in ASCII mode, select Use Favorite Settings under the ASCII File List drop-down option.
Click on the New button and type in the file extension that will be transferred in ASCII mode under Value.