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911 Dialing / Phone System Limitations

Phone Service Limitations

VOIP telephone service differs from telephone service offered by traditional telephone carriers, including how 911 calls are handled. Some of the most important differences are explained below.

VOIP telephone service (the “Services”) will not function if a customer loses electrical power, if the customer experiences interrupted connection to its internet or network service, or if the customer cannot connect to the VOIP platform due to a network or technical issue. These limitations also apply to 911 Dialing.

The Services, including 911 Dialing, may not be accessible from a particular phone or other calling device if that device is not configured correctly or otherwise malfunctions.

The Services are not set up to provide the autodialing functionality sometimes relied on by security systems, medical monitoring equipment, TTY equipment, etc. Customers should not rely on the Services to provide this functionality.


Enhanced 911 (“E911”) service is 911 service which includes automatic forwarding of location and callback information to emergency responders at a 911 answering point. Automatic forwarding of this information can assist emergency responders and can facilitate callback if a 911 call is dropped before completion. The information forwarded by the E911 system is called Automatic Location Information (“ALI”) and Automatic Number Information (“ANI”).

To facilitate E911 service, the provider requires each customer to register a physical address for each calling device. The customer must provide an accurate and physical address for each device. The customer must also provide an updated address if the physical location of a device changes.

After a customer provides address information for a device, there may be some delay before automatic forwarding of ALI/ANI is enabled.

A device’s registered address is the only means by which to route a E911 call to the geographically-assigned E911 answering point. Therefore, if the customer registers incorrect ALI/ANI information, E911 call routing may not function correctly. If the geographically-assigned E911 answering point is unavailable, E911 calls may be forwarded to a different 911 answering point.

Some 911 answering points are not equipped to receive ALI/ANI information. When an E911 call is directed to a 911 answering point that isn’t equipped to receive ALI/ANI information, the caller will need to provide location and callback information verbally.

As with 911 Dialing generally, E911 service will not function if the Services do not function and will be inaccessible from a particular device if the Services are inaccessible from that device.

Notice to Users of 911 Dialing

Each customer is responsible to notify any individuals who may place calls using the Services of the limitations of 911 Dialing as described in this policy.

In light of the limitations of 911 Dialing discussed above, we recommend that each customer maintain 911 failover services or another alternate means to access traditional 911 dialing service, such as a cell phone.