This in particular caught my eye, discretely buried in the (excellent) article:
"
And AT&T continued to improve the technology at work in its infrastructure. The transistor, invented at Bell Labs in 1947, eventually allowed for digital, solid-state switching technology to replace electromechanical switches.
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" And AT&T continued to improve the technology at work in its infrastructure. The transistor, invented at Bell Labs in 1947, eventually allowed for digital, solid-state switching technology to replace electromechanical switches. "