Fairly often cellular systems are connected by fiber optic lines. Ditto on internet/control systems having trunk connections. The fiber lines are clearly marked with orange trim or a placard message “Optical Fiber-Do Not Dig!” for protection against backhoe assault.
All phone calls go through a switch. This has not changed since my working in telephony in the 80s and 90s.
All phone calls go through a switch. This has not changed since my working in telephony in the 80s and 90s. Take out the switches and it’s over. They has enough enough backup power for 3 days.