In 1947, a team at Bell Labs led by William Shockley discovered how to switch and amplify electronic signals using semiconductor material. It was the first transistor. A decade later, many of them were crammed onto a small chip, dubbed an integrated circuit.
Before the transistor, electronic products worked with bulky vacuum tubes. Now computing power could be miniaturized, a breakthrough that led to small radios, personal computers, cellphones and an array of other devices today.
In 1971, the first email was sent by a Defense Department computer engineer.
The same year, John Blankenbaker built the Kenbak-1, the first computer small and cheap enough for the masses to buy. They didn't. Fewer than 50 Kenbak-1s were sold, mostly to a community college, according to oral history by Blankenbaker at the Computer Museum in Boston. His company went out of business within two years
In 1981, the National Science Foundation set up a network linking university computers, a milestone in the development of the Internet. Its impact could scarcely be imagined then.
The past three decades, new products and innovations have allowed people to entertain and inform themselves anywhere, anytime.
In 1983, Motorola introduced the first portable cellphone, a 2-pound clunker called the DynaTac 8000x. In 1984, the first PDA, or personal digital assistant, was sold — the long-forgotten Psion. In 1994, BellSouth sold its first Simon, the start of a stream of ever-smarter smartphones from which you can access virtually any information while on the run, including that staple of the telephone operator — a phone number.
Which helps explain why there were just 36,000 U.S. operators in 2010, down nearly two-thirds in 10 years.
A job that rose in the same period? Software engineer. They numbered 1.03 million in 2010, up nearly 40 percent.
AP researcher Judith Ausuebel in New York contributed to this story. You can reach Bernard Condon on Twitter at http://twitter.com/BernardFCondon