Lovely 1920s instructional film made by AT&T which Quentin found. It makes an interesting point which has a contemporary resonance, namely that technologies which once seemed strange can become so commonplace as to be invisible. It’s impossible to imagine a child growing up nowadays in Western society who did not instinctively know how to use a phone. But there was a time when a telco felt it needed to produce a movie to introduce customers to its new-fangled device.