Lync Server 2010 and Lync 2010 supports dialing emergency services using Enhanced 911 (E911) in North America. You configure the emergency dial string through the EmergencyDialString parameter to CsLocationPolicy and the value is sent to the Lync client through in-band provisioning. In the screenshot below you can see I have configured it to 911 and set the EmergencyDialMask to 112, which is the number used in Denmark.
When you dial the emergency number in Lync 2010 you will see that the client automatically employ an internal normalization rule, which prepends + in front of the number (see screenshot below). Don’t be alarmed, this is done on purpose to prevent other normalization rules kicking in and in that way potentially re-routing the call to another destination than the emergency service.
When the call is connect you’ll see a notification in the client that is an emergency call and that it is connected to the emergency number. See screenshot below
Depending on the way you are connected to the emergency service you might want to create an outbound translation rule on the trunk configuration to remove the + from the emergency number.