I'm having a lot of trouble with terminology. For instance I
expected books to index this subject under "RS-232," "Serial,"
and "Port." Now I see it's indexed under "stty." I'm looking for a
command that sends a file through the cable so I can observe the
result on a break-out box.

Physically the each cable has a USB connector, about one meter of
cable, a box or bulge, and a short bit of cable to an RS-232
connector. I'll try to have some information when I come to the
internet coffee house tomorrow.