Phone Tones: The hidden language of phone number beeps
Twenty Thousand Hertz
00:00
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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