I joined the fed-gov in 1985 and we still used teletypes for secure coms. I think we transitioned away from them around 1988 or 89 and went to secure fax machines.
In the late 80s and very early 90s I remember communicating with a sponsor (government) over the remnants of what was ARPANET. After that, electronic comms exploded and teletypes were relics (except for the State Department, I guess).
“teletypes”
That’s a word I haven’t heard for decades.