Erna Hoover

Computerized Telephone Switching System
Computing and Telecommunications

One of the most well-rounded American inventors since World War II is Erna Schneider Hoover. She earned a BA with honors from Wellesley College in medieval history and a PhD from Yale University in philosophy and foundations of mathematics before teaching for some years at Swarthmore College. Finally, in 1954, Hoover accepted a research position at Bell Laboratories in northern New Jersey. There she created a computerized switching system for telephone call traffic and earned one of the first software patents ever issued.

Hoover was in the hospital after giving birth to one of her three daughters when she drew the first sketches of her system. At the time, Bell Labs, overwhelmed with the number of calls coming through, wanted to replace their hard-wired and mechanical switching equipment with a more complex and efficient system. Hoover's solution was to use a computer to monitor the frequency of incoming calls at different times and to adjust the call acceptance rate accordingly. By putting a simple theory into practice through the complexities of computer programming, Hoover eliminated the danger of overload in processing calls.

In addition to patent #3,623,007 (Nov. 23, 1971), Hoover's system earned her a position as the first female supervisor of a technical department at Bell Labs. The principles of Hoover's switching system are still widely used today, as various communications companies struggle with ever-increasing incoming traffic.