Many parts of rural Prince Edward Island (PEI) has DSL running on a phone system that’s probably original from modernization initiatives in the 1960s - 1980s. Party lines were the norm in some areas up west until late-1980s.
Back when a whole family had the same number and you had to ask whoever answered that you want to talk to so and so. Now days everybody has their own number and with caller id you (sometimes) know who is calling.
My daughter is gonna grow up not knowing any of the “shared phone line” etiquette because it is largely obsolete.
The party lines I’m talking about are shared loops between a group of residents in a rural area.
Some of the first-hand accounts I’ve read talked about neighbours listening in on conversations. People could tell a snooper was on the line because the volume of the other caller would drop. There was a social aspect to the whole enterprise because you could tell the one nosy neighbour to get off the line and the volume would magically raise.
Front door etiquette still works basically the same way. A doorbell rings and the whole house hears it. Once person goes to answer it, then passes off the conversation to whoever it's actually for.