I have LLDP working with my Aastra 57i phones for auto VLAN provisioning. There is also a feature in LLDP for ELIN where the phone will change the CID to what is set on my switch if 911 is dialed. According to Aastra documentation
The 6757i IP Phone supports Link Layer Discovery Protocol for Media Endpoint Devices(LLDP-MED), and Explicit Congestion Notification (ECN) Emergency Location IdentificationNumber (ELIN). LLDP ELIN allows the phone to use the location information sent by the switch,as a caller ID for making emergency calls
Do I need to do anything in my outbound route, extension or trunk to allow this to work properly? All of our extensions begin with 1#### and they can dial long distance and 911 directly without using a prefix. I am in a small campus environment and each building has a different physical address. If I can set the emergency number this way, city/public 911 operators can properly determine where the call is coming from rather than it looking like the main building. Each building has an emergency DID associated with it with the correct address attached to the DID. I have tried the emergency CID under extension in the admin panel but that fails quickly when the user moves to a different building for a day and signs in with their extension (this happens quite often).