General Toll Switching Plan
The switching plan was principally operated by the Long Lines division of the Bell System in cooperation with independent telephone companies under the decree of the Kingsbury Commitment, reached with the United States government in 1913.
Solutions had to be found for organizational structure, management, business relationships, collaboration, to operate telephone services between or across multiple communities.
Theodore Newton Vail, General Manager of the American Bell Telephone Company, created the vision for this endeavor.
He refined a vision of service, shaped new goals for supporting technological progress, and reorganized the company to facilitate his ideas.
[8] On December 19, 1913, in a letter by Nathan C. Kingsbury to the U.S. Attorney General, AT&T conceded to restrictions in the acquisition of independent companies, and agreed to the divestiture of Western Union.
Telephone companies negotiated interconnection with neighboring businesses and built localized toll networks that addressed the regional needs of their customers.
[12] By 1911, the Long Lines network had reached from New York as far west as Denver, using loading coil circuits, but this distance was the limit for communication without amplification.
The research efforts at Western Electric, committed to by Vail in c. 1909, into the principles of the electron tube recently invented by Lee de Forest, the Audion, and its efficient manufacture made it possible to build signal repeaters that extended the transmission distance of toll lines.
Due to the investments in the plant, the average speed of establishing connections was steadily decreasing throughout the 1920s,[15] AT&T was able to effect several rate cuts in long-distance service in just a few years.
[16] A systematic approach was needed to limit the number of intermediate toll offices that relayed the calls across the country, to further reduce set-up time, and to establish technical parameters for interchange points to assure a certain level of circuit quality.
The purpose of this plan was to provide systematically a basic layout of the plant compatible with the highest practicable standards of service achievable within given economic goals.
The layout of cabling and major toll centers needed optimization in the number of switching steps required along a given route to connect any two telephones on the continent.
In addition, they connected to some Primary Outlets in other regions as well, as traffic demanded, or for alternate routing in case of congestion or technical failures.
