The Bell System put its first test call through a laboratory
> Electronic Switching System in 1958 and had a prototype system in
> public service in the early 1960s.
> Would anyone know when other telephone companies, either in the
> U.S. or abroad, developed and implemented their own ESS? For
> instance, when did Automatic Electric put one in service?
Electronic switching systems were being installed in the late sixties and into the seventies. Bell System used Western Electric #1ESS, GTE used Automatic Electric #1EAX and #2EAX. North Electric (independents) used NXUN2 IIRC. Probably Stromberg-Carlson had something going as well (XY?) I'd guess that Northern Electric (now Nortel) probably manufactured #1ESS as well prior to their making DMS digital switches.
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