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

Answer 2

There was no dialing invented yet. Connections were still manual. You turning the crank alerted an operator who would direct your call. If they were in another area, they would call operator to operator until they got to the one you wanted. That operator would make the final connection.