Super old phones require a winding motion before use?

Question

I’m watching an old movie and there’s a phone mounted on the wall, and the caller grabs the piece that they are going to listen in and then winds a crank on the other side of the phone before listening for the operator. What is the crank for, what does it do?

It looks like this phone:

https://www.lofty.com/products/antique-c-1910-western-electric-hand-crank-oak-wall-phone-model-317-n-1-rsbew

In: 4

Answer 1

Phone lines are electrically powered and the crank was a generator used to power the ringing on the other end.

The ringing would alert the operator to pick up the circuit.

https://en.wikipedia.org/wiki/Telephone_magneto