snipped-for-privacy@bbs.cpcn.com asked: "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?"
See BT's online museum, Connected Earth .
BT's ancestor, the British Post Office, tried and failed in 1962 with a switch at Highgate Wood, north London: "The main problem was digital electronics 'crosstalking' with switch contact points that were still working in analogue mode. This meant, for example, that sometimes the exchange systems would ring numbers, seemingly of their own volition ... "
It put a successful TXE2 reed relay exchange at Ambergate, Derbyshire, in 1966, and then inaugurated another switch, at Empress in west London, claimed to be the first in the world to switch PCM signals from one group of lines to another in digital form.
Alan Burkitt-Gray Editor, Global Telecoms Business magazine
(PAT - please don't use my personal email address, from which I'm sending this.)