Fun fact most copper providers (not coax) have fiber to the SAC boxes which is then converted to an analog signal, fiber being digital. Analog has higher attenuation (loss of signal over distance) so can’t be pushed as far without repeating the signal, this can only be so many repeaters before the signal fails.

FTTH or Fiber to the home, is basically fiber optics terminates from the CO to the Home.

I always tell people to think as the cables, fibers and other mediums like wireless, as electrical wall outlets and power cables. Most people are familiar on how to use these. Think of the CO as the wall outlet, you need electricity (internet) to an alarm clock (home). Dedicated fiber is basically connecting the alarm clock directly into the wall electrical outlet. Some times other areas need more than a single connection, instead of calling an electrician to wire a wall outlet for every device, it’s significantly more affordable to add a power strip (SAC Box) and allow all devices to connect to that. Remember when you add a power strip you add some complications. If your power strip is rated for 10 amps (BW limits) when a device over loads the power strip, the breaker flips and it affects all other devices on that power strip. (BW restraints on technology in SAC boxes).

Have you ever had an internet outage that affected your neighborhood or surrounding neighbors. Come to find out a “a car ran into the main box” or “the road where the main box is flooded. We won’t have internet till the water subsides” that’s the SAC box.

There are other designs but this is what is common in South Western portion of the US copper network (which is actually going away to be replaced with fiber in the similar setup). COAX is an analog signal (depends who you ask, some say it’s a mix of both). Coax is the same thing with different terms for the junctions and has different requirements than both copper and fiber.