they used microwave links for point to point connections to other COs
an old AT&T video phone that worked over phone lines (with a slow bad picture due to line limitations)
check out the thousand+ amp switch with heavy copper
later semi electronic phone switches used boards like these, but they are impossible to fix or replace
it's fun to hand connect a thousand+ phone lines by hand in a conduit
a 68k based Sun3, sweet (although it was slow)
the CDC 6600 was the first supercomputer before the Cray1
we had a Amstrad PC1512 at home
we also had an Atari STF and later STE
Dongeon Master, I remember spending so many hours with this game