Phone confusion

I was woken up this morning to the phone ringing repetitively downstairs.

A few minutes later, a knock at my bedroom door.

"Your phone has been ringing off the hook, I just thought you might want to know."

"Uh, my phone is in here. That's your phone."

"Oh. Well they sound the same."

"Your cell phone and your land line?"

"Well, I knew the landline was for me."

We both really have trouble with this whole, phone-answering thing.