Cell phones can't do everything- not yet

We were having a dinner conversation and for some reason Ethan brought up "coin-in" phones.  David and I looked at each other and asked him what he was talking about.  He said, "you know, the phones that you put a coin in."  So we asked Maddie what she would call those phones.  She said they are "wall phones".  We asked them if they every heard of pay -phones--blank stare.  So we asked if they knew what an operator or collect call was- blank stare.  When we told them about collect calls they asked why the person just didn't use their cell phone instead.  This brought on a whole new conversation about land lines and how if there were 2 phones in the house you could pick up when your siblings were talking to boy or girl friends and listen.  Maddie and Ethan were fascinated with that and thought it sounded so cool.   You can't do that on a cell phone.