Back in the '60s I worked for a Paging and Intercom company. They had their own "Muzak" - banks of tape decks that sent out signal over telephone company leased lines. These worked fine all over the city.
We would routinely do jobs for Garment Center companies - A showroom on 7th Avenue or Broadway and a factory on the far West side or across the river in NJ. Each side would have it's own amplifier, speakers and Intercom system (this predated Interconnect).
We would connect the two sites with leased lines and they could page the other side and then talk to each other. We routinely did this over many miles of Telco copper wire.
One morning we came in to dozens of trouble tickets. None of our remote paging to/from NJ was working! Over the weekend, NY Tel had converted all the cross-Hudson circuits from copper to Carrier. Woops!
But everything worked fine over long distances of copper OSP.
Sam
