On 21.05.2021 12:14, R.Wieser wrote:
Herbert,

Why not use a communication program?

:-) The idea is that I would be able to transfer a program to a 'puter
running a basic OS (DOS - old or new) that does not yet have such a
communications program available.

But in real DOS, the "copy com1 file" should work.
Also INTERLINK.EXE/INTERSVR.EXE was part of DOS.