Stan Sieler asks:
but...does anyone know the first data of a binary (not
ASCII)
file transmission via modem?
I assume that was a typo, and you want the date, not the data?
(I know of some done in 1975, from an IBM
mainframe to a DG Nova.)
At least as early as 1965 IBM sold equipment that could do this, so
I rather imagine people probably did binary transfers even in those days,
but I don't have any proof of it.