With a mainframe, your choice is limited. Usually it is an FTP to a text
file. The internal format will be tab or coma delimited (or if you are old
school, fixed width fields)



The FTP will take care of the conversion from EBCDIC to ASCII.



Some terminal emulators also include a file  transfer mechanism. SAG's Entire
Connection (a Adabas/Natural environment) will transfer a file in Excel
format.