Question : PRI inbound calling failover, Cisco Call Manager

Imagine you have site A in Maine with a PRI and pilot number 207-111-1100. 100 DIDs.  The gateway is a Cisco ISR say a 3845

And site B is in San Francisco with PRI and DIDs 415-111-1100.  The gateway is a Cisco ISR.

The Maine site is a call center.  A backhoe causes the PRI to go down.  You have arranged with the telephone company to route your calls to the San Francisco PRI in the event of something like this happening.  

What would need to be configured in Call Manager so that calls to the Maine DIDs are accepted received at the San Francisco PRI and routed to the phones in Maine??

Answer : PRI inbound calling failover, Cisco Call Manager

You don't need to do anything apart from ensure that both gateways are sending their calls to callmanager and the appropriate translations are occuring so the called number matches what is in callmanager. Also ensure that the calling search space on the gateway in callmanager allows that gateway to call that number.

Callmanager doesn't care where a call comes from, only what the called number is.