Business Impact

Software Switch

Erna Hoover unjammed the telephone switchboard-from her bed in the maternity ward.

In 1947, bell labs launched a revolution with the introduction of the transistor, enabling everything from radios to computers to be made smaller and more cheaply. The transistor also made possible a less visible technology, one that allowed telecommunications to explode: electronic telephone switching. But the transistor was only one component of this development. Without software created by a researcher during her recovery from childbirth, the highly automated, computerized telecommunications age we take for granted would have been on indefinite hold.

In 1952, Bell Labs began exploring the development of electronic switching systems (ESS) for use not only by the public telephone systems but also for private business exchange systems. A newly hired researcher named Erna Schneider Hoover joined the team in 1954. Hoover was not a typical team member: not only was she female, but she came to Bell Labs with a degree in medieval history from Wellesley College and a doctorate in logic and philosophy of science from Yale.

Hoover contributed to the development of innovative software for stored program control (SPC) systems that processed calls in real time. After the birth of her first daughter, colleagues had difficulty convincing her to take her planned maternity leave. Then, while in the hospital after giving birth to the second of her three daughters, Hoover sketched out the first plans for a program to monitor the frequency of incoming calls and automatically adjust the acceptance rate, eliminating the danger of system overloads.

This story is part of our April 2001 Issue
See the rest of the issue
Subscribe

Hoover’s innovation eventually earned her a position as the first female department head at Bell Labs. And in 1971, it earned her one of the first software patents ever granted.

The first stored program control system went into service in a private business in 1963. Shown above, Bell’s No. 1 ESS went into commercial service in the public network in 1965. By 1983, 1,800 of the switching systems served 53 million subscriber lines. Today, businesses and public systems alike are using a direct descendant of the first system: AT&T’s No. 5 ESS. Even the Internet relies on SPC to help route the billions of e-mails coursing through the system daily.

Tech Obsessive?
Become an Insider to get the story behind the story — and before anyone else.

Subscribe today

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

More from Business Impact

How technology advances are changing the economy and providing new opportunities in many industries.

Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look: exclusive early access to important stories, before they’re available to anyone else

    Insider Conversations: listen in on in-depth calls between our editors and today’s thought leaders

  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus ad-free web experience, select discounts to partner offerings and MIT Technology Review events

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning magazine and daily delivery of The Download, our newsletter of what’s important in technology and innovation.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

/
You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.