UseBinary - denotes the datatype for file transfers. The 2 modes of file transfer in this case are Binary and ASCII. At bit level both vary in the 8th bit of a byte. ASCII uses 8th bit as insignificant bit for error control, where as, for binary all the 8 bits are significant. So take care when you go for the ASCII transmission. To be simple, all those files that open and read well in notepad are safe as ascii. Executables, formatted docs etc should be send using binary mode. BTW sending ASCII files as binary works fine most of the time.
UsePassive - specifies to use either active or passive mode. Earlier active FTP worked fine with all clients,