An evening pause: I would not be surprised if some of the younger readers of Behind the Black would need the instructions in this silent film in order to properly use a rotary phone.
Introducing any new technology requires instruction. This was strange stuff to homeowners in 1927, but a great improvement over party line phones that required an operator to do the dialing. And this was cutting edge then, and a symbol of the future.
Hat tip Jim Mallamace.