There will be a big battery bank in each telephone exchange that supplies power until the generators start up. I always hated the battery room, it smelled and there was always the danger of hydrogen buildup. The telephone exchange can keep running on generators until mains power comes back on, or the fuel runs out. (The longest outage I’ve experienced personally on generators was 3 days). The expectation is always that mains power will be restored “soon”.
There will be a big battery bank in each telephone exchange that supplies power until the generators start up. I always hated the battery room, it smelled and there was always the danger of hydrogen buildup. The telephone exchange can keep running on generators until mains power comes back on, or the fuel runs out. (The longest outage I’ve experienced personally on generators was 3 days). The expectation is always that mains power will be restored “soon”.