Emergency Routing is where you will go to turn on your emergency back up number that, when you check the Enable Emergency Routing button, will route all calls to this number.
To get to Emergency Routing: Configuration>Pulse Setup>Emergency Routing
As the Page Help on the right side of this page states:
This featured should only be used during emergency situations, such as the loss of power to your primary call center. Enabling emergency routing will forward all calls to the override number and will disable call tracking, routing and recording features.