1) 911 Calls should be routed via Primary Voice Gateway in the same building (FXO Lines etc.). Meaning each building should have its own Voice Gateway Router. If goes down, then
2) 911 Calls should be made via a Red Phone (described in my last section., if not working, then
3) 911 Calls should be made via Secondary Voice Gateway in the main building if the Primary Voice Gateway in a local building goes down. The problem is that PSAP will not see the correct building address as it will display the address of the main building, not the address where the emergency occurred.
4) Non-Emergency Calls should be routed via Centrally Located Voice Gateway in a Main Building.
5) Non-Emergency Calls should be routed via Local Voice Gateway if Centrally Located Voice Gateway in a Main Building goes down or the fiber connection between the buildings go down.
In a Campus environments, emergency calls should go to the Campus Security/Campus Police regardless of where the call made from so the Campus Security or Campus Police can escalate the 911 personnel to the correct area as they are familiar with the campus.
If there is a power failure, then unlike legacy phone system, nothing would work, and what to do if emergency occurs. In this case, Cisco recommends to have dedicated lines coming directly from Telco in each area that are not power dependent. The Red Analog Phones can be connected in each area directly to those lines to protect 911 Calls.