99Emergency 911 - Operator control ofdisconnectOverviewFor Emergency 911 services to be effective, it is vital that a system maintain a connection with the 911 operator until the user provides all necessary information. In traditional 911
telephony, if a 911 call is disconnected before the necessary information is provided, mechanisms are in place to allow the 911 operator to ring back the calling party.
In VoIP calls, 911 support is an evolving standard.
If the user of an IP Phone E attempts to disconnect a 911 call after the operator has answered, the IP Phone E switches to hands-free mode. Once the IP
Phone E is in hands-free mode, the 911 call can only be disconnected by the operator.
Emergency 911 calls originate on the IP Phone E and are completed by the Call Server. The Call Server communicates with the 911 network or systems for routing,
call control, and location information. Although the
IP Phone E allows users
to enter location information, this location information is not used by all Call Servers. Some Call Servers derive the location information based on the number and location databases.
Characteristics of Emergency 911 calls and limitations of Emergency calls using the IP Phone E are given below.
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