Re: Phone number formats
I am also in the US ... The small community where my parents grew up has one of the last party line telephone systems in the United States. We decommissioned it "officially" in 1972. After disconnection, $TELCO left us the obsolete equipment to dispose of as we saw fit.
Unofficially, it still works between two dozenish homes, mostly family members. It is possible to call me there by dialing one of two numbers we maintain specifically for the purpose, and then having the operator (or a computer, on the second line) patch from $TELCO to our party line[0] and then ring the requested number.
In the other direction, four short rings automatically patches you to an outside line, normally used for emergencies only these days (thus the computer controlled line ... the human operator is an elderly cousin). Then you rattle the hook to tell the computer what number to dial. Yes, it's slow to dial out ... but it has saved lives on at least two occasions; cell phones don't work well or at all in this part of the Mendocino County back woods.
Mostly it's used for birthdays, anniversarys and other family stuff like that. My "number" (inherited from my Grandfather) is two shorts & two longs.
[0] Don't panic ... it's legal, I built a couple optically isolated circuits specifically for the purpose.