Sometime in the late 1950s, I visited the studios of WOW-TV (now WOWT) in Omaha. I noticed several telegraph keys scattered around the control rooms. I wondered about them, but I didn't say anything.
Then I figured it out. The engineers (all hams) were communicating among themselves by Morse Code over a hardwired telegraphic party line. Keys and speakers were located near every control board, and among the equipment racks. Any engineer could talk to the rest of the group by Morse code. Of course, non-engineers could hear the communications, but (presumably) couldn't understand them.