The video reminded me of something from my high school days. The computer lab was Apple II's, some actual Apples and some of those black Bell and Howell models. We had an ordinary dot matrix printer, an Epson or similar, but there was also one leftover relic, a Teletype Model 43, with an acoustic coupler, and there was a live telephone right there. They also had it hooked up to one of the Apple IIs as an extra printer.
First up, this model still had a physical bell that rang with Control-G. So I wrote a convenient program that mimicked the ringing of a telephone. When we had a substitute teacher, it was basically free lab day, so I set this up on that machine, and then moved over to a different one. I had a time delay built in so it wasn't obvious. Ring ring, ring ring... a few rings then it would stop. Sub came in, picked up the 'ringing' phone - nothing but dialtone. Few minutes later - repeat process.
But, relevant to this thread, we found out the phone line was a dedicated POTS line, didn't go through the main office switchboard, so we could call out or do whatever. So my friend and I would spend a lot of time on some local BBSes. Several boxes of 11x17 greenbar fanfold paper later... For whatever reason I kept much of this as a log of what I was doing, not that any of it was really earth-shattering, but I had all these long printouts for a while before i finally tossed it all. At home I was getting on the same boards with my TRS-80 Model 4P, and in fact had one of the modems shown in the video, direct connect to the phone line but manual answer/originate and no dialing capability. Another friend of mine actually modified one of them so that it could auto-answer, he had TRS-80 Model 1 and write, in all assembly, a purely memory-based BBS system - all message threads were completely stored in RAM, no disk files whatsoever. In those days, 300 bps wasn;t necessarily the limitation on communications speed - except on his board, with everything in RAM and the code being assembled machine code, it could send a steady 300bps with no delays.
Wish I still had all my code - I wrote several systems in BASIC on my 4P, including one that did matchmaking based on answers to a range of questions each new user had filled out - long before Match.com or any of that stuff. If I still had the disks and code, I coulda sued them LOL.