cu(1) on FreeBSD
The text 6b07b9ddcf74, as FreeBSD 14.5-RELEASE, FreeBSD 14.4-RELEASE, FreeBSD 14.3-RELEASE, FreeBSD 13.5-RELEASE shipped it.
call UNIX over a serial line
Flags it lists
-
-a -
-e -
-h -
-l -
-o -
-t