Came across this interesting show
https://archive.org/details/analog-telephone-syssystem-show
while exploring the WBCQ archives
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Being an ex telephone CO tech engineer I really feel some nostalgia listening to that… In my country we had the European/British system and I’ve saw personally it’s evolution from the rotary selector days, passing trough the crossbar systems to the latest evolution of copper lines on digital CO’s. nowadays everything runs on fiber and VOIP systems and I’m literally out of work now, no space for the “old timers” any more on the telephone tech industry… 
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