Western Electric No. 1 ESS Circuit Pack

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Description (Brief)
As inventors refined telephone equipment during the late 19th and through the 20th centuries, they introduced automatic switches that worked faster and could handle more calls than human operators. As they began introducing computerized switching equipment new advances in software proved necessary to make best use of the more capable technology. In 1971, Erma Hoover and Barry Eckhart received U.S. Patent 3,623,007 for a method of processing tasks in an electronic switching system. Their invention served to flexibly prioritize operations in the computer so that surges in the number of calls would not slow the telephone system. Hoover received her Ph.D. from Yale and ultimately became supervisor in the systems engineering department of Bell Labs. This three-part circuit board performed a “low-level logic” function in Western Electric’s model no. 1 Electronic Switching System.
date made
Western Electric
Physical Description
fiberboard, metal, plastic (overall material)
.01: 3 3/4 in x 3/4 in x 7 in; 9.525 cm x 1.905 cm x 17.78 cm
.02: 3 3/4 in x 3/8 in x 7 in; 9.525 cm x .9525 cm x 17.78 cm
.03: 3 3/4 in x 3/8 in x 7 in; 9.525 cm x .9525 cm x 17.78 cm
ID Number
nonaccession number
catalog number
See more items in
Work and Industry: Electricity
Inventing In America
Exhibition Location
National Museum of American History
Data Source
National Museum of American History


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