we have some users who are using extension mobility in multisite environment. How can I address 911 dialing if users login to phones in different locations. do I have to use Emergency Responder or it's something we can set it up without it?
any suggestion would be very appreciated.
That is why the line CSS does not contain any route patterns. It only contains blocks for what the DN is not allowed to dial. All routing is done at the device CSS.
You may want to read the Dial Plan chapter of the UCM SRND for additional detail.