Imagine this scenario. All the telephones in the US operated without dials, all depended on a human operator connecting your call by hand. No phones had dials.

City by city, AT&T had to roll out new equipment, giving rotary dial telephones to everyone. They put out this message via a newsreel shown in the town’s movie theaters:

At midnight Saturday the telephones in this city will be changed to dial service and all telephone numbers will be changed.

What an incredible problem to have to solve. Completely replacing an almost universally used installed hardware base overnight. No early adopters. Everyone gets a new phone and your old phone will stop working at midnight.

Here’s the video. Fascinating.