since they had discovered by then that not all of the
>U.S. is served by great megaplexes and there was also
>a need for dial equipment for smaller cities where
>common control would have been, to put it mildly, an
>absurdity.
>
There was the Leich crossbar system used by independent companies in small places - but I don't know enough about it to know how much it was common control.