Israel’s Carbyne (see here previously) has joined with AT&T to launch APEX Continuity, a solution to keep 9-1-1 emergency call handling operational during network disruptions, cyberattack, or evacuation. APEX reroutes calls to continuity backup support facilities.

https://carbyne.com/resources/press/carbyne-and-att-launch-apex-continuity-for-uninterrupted-9-1-1-call-handling-for-att-customers/