For decades there was one phone in the house. The first phones were on the wall the and the caller had to crank the phone to alert the operator who would then connect you to the proper line.
When I was growing up, most homes has one maybe two phones. Two phones was a luxury, however only one person could make a call at a time.
I grew up at a time when most phones has long cords and at night went with your parents in their bedroom We couldn’t received calls on a school night or after nine.
Whenever, I would tell my mother it wasn’t fair-I should be able to call anyone I wanted to, she would remind me that she paid the bill AND if I wanted a phone, I could have one in my house!
Back in those days, are parents knew who we were talking to,there were no old men talking to 13 year old girls. In the homes where there were two phones, if she sensed something was strange, she might pick up the other line and listen in.