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No. 4 Electronic Switching System

The No. 4 Electronic Switching System (4ESS) is a class 4 telephone electronic switching system that was the first digital electronic toll switch introduced by Western Electric for long-distance switching. It was introduced in Chicago in January 1976, to replace the 4A crossbar switch. The last of the 145 systems in the AT&T network was installed in 1999…

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Overview

System architecture

History

Next-generation 4ESS

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Map overview Semantic statistics

No. 4 Electronic Switching System

Nodes36
Edges35
Triples7
Avg. degree1.94
Density0.055556
Components1

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Important terminology

4ess network switch switches processor switching system equipment interface used toll bell peripheral also tandem units provides includes 4eaps n4e-n1b

Entity relationships Subject–Predicate–Object triples

SubjectPredicateObjectConfidenceSrc
Vaughninstance ofvisionaries0.80text
Oliver recognized that the network would eventually become digitalinstance ofvisionaries0.80text
requiring digital switching technologies.The last 4ESS was installed in suburban Atlantainstance ofvisionaries0.80text
GA in 1999 as a toll tandem for ATinstance ofvisionaries0.80text
MRV console terminal servers.Starting in the late 2010sinstance ofand includes other elements0.80text
continuing in the early 2020sinstance ofand includes other elements0.80text
ATinstance ofand includes other elements0.80text

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