Well, that's a departure from the other proposals Just to be on the
safe side, I'm going to get tomorrow both a buzzer and a 75 ohm
terminator!

I already have a 9v battery and even a multimeter - analog,
unfortunately, but it does measure resistance, so I should be all set
(assuming by wife agrees to act as the assistant...)

As an aside, I must say it NEVER occured to me how useful a multimeter
is. Talk about learning something new every day.