Home Phones used to use something called "POTS" or plain old telephone. It honestly was very cool and had several advantages. For instance, if you recall there was never any power adapter for old phones... that is because the line was powered by the provider not the user.
POTS is been done away with for newer standards, and other products that needed those existing lines. For example, DSL or digital subscriber line, used the same lines POTS did but used a different standard to provide home internet.
I digress, Modern home phones use the VIOP protocol, or Voice over IP. it just makes the phone call over the internet reducing the need for specialized infrastructure by the phone companies and us... won't work if you lose power though.
