I liked An Answer for Linda (1961), which shows the work of outward toll operators using mark-sensing call tickets at traditional (3CL) cord switchboards. “Watch Billie closely, as she handles a group of typical calls.”
(I won’t spoil the Answer; you’ll have to watch for yourself.)
Snap Out of It! (Emotional Balance) (1951) https://youtu.be/mD9gQUh7m0k