Excerpt:
AT&T brought its former president, Theodore Vail, out of retirement to help it fight off competition erupting from the expiration of Alexander Graham Bell's telephone patents. Vail's solution: transcontinental telephone service.
In 1906, the eccentric American inventor Lee De Forest developed a triode in a vacuum tube. It was a device that could amplify signals, including, it was hoped, signals on telephone lines as they were transferred across the country from one switch box to another. AT&T bought De Forest's patent and vastly improved the tube. It allowed the signal to be amplified regularly along the line, meaning that a telephone conversation could go on across any distance as long as there were amplifiers along the way.
Annotation:
This television-program related site is dedicated to the transistor, an invention described as the most important during the 20th century. The exhibit features articles on the electron, vacuum tubes, transistors and William Shockley, Morgan Sparks. Audio-video clips often compliment the essays. The site can be browsed chronologically or by topic and is searchable. Though tailored to an audience that extends beyond academics, the information may prove useful for filling in gaps in research or for beginning research.