Party lines + modems
I lived in rural Colorado (US) back in the 70s and for telephones, we had party lines. This was where 4 houses were on the same POTS line and you got 1, 2, 3 or 4 rings to indicated which house should pick up the phone. Of course the other houses could pick up and listen in but generally speaking, people behaved back then.
I - being an engineer at DEC and a geek to boot - had a desire to dial into the department computer (*) from home. 300 baud Hayes modems and party lines don't mix. I wound up getting my own dedicated party line. I don't recall how much it cost. As noted, there were warnings and prohibitions about connecting 'weird' stuff to the company's lines which everyone ignored.
* An RSX-11M machine named BALROG