3min chapter

Twenty Thousand Hertz cover image

Phone Tones

Twenty Thousand Hertz

CHAPTER

The Stroger Switch

In Kansas City, an undertaker wanted to stop his rival from stealing his business. He designed what would become known as the Stroger Switch; it didn't have a dial at the time. The phone company developed a new switching machine called the number four crossbar. This was the first time a keypad of numeric buttons was widely adopted.

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