OK, as another example, when most of us were growing up, we had corded phones or cordless. But you still knew what an old phone looked like, where someone took off the the earpiece and spoke to the operator, "Baker 357 please." You probably knew what a party line was.
Today's kids might not get those references without a bit of setup, but I think that corded phones are to them what party lines were to us.
Then again, if it doesn't work, it could be a cordless, or even an internet phone. My cordless phone (which does have a dialtone) gets knocked off sometimes, and a few times, the router needs to be rebooted or whatever. Maybe somebody unplugged the router or dock or knocked it out when vacuuming or something.