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As is the case with all technologies, the systems underpinning the emergency telephone number used in the North American Numbering Plan have evolved since 911 was introduced more than 50 years ago.
Original 911 services, for example, didn't have the ability to automatically detect the owners of the calling phone number -- nor the address they were calling from. That changed in 1999, when the federal government mandated Enhanced 911, or e911. Today, however, E911 has again fallen behind the times in two important areas. Let's look at those shortcomings and examine how Next Generation 911 (NG911) standards solve them as they bring emergency services up to modern technology levels.
The first advantage NG911 brings is that it is IP-based. As a result, calls placed to 911 can fully bypass the legacy public switched telephone network (PSTN) when connecting to emergency services. It also means that IP-enabled communications devices can reach out to 911 services through voice as well as SMS, video and photo sharing.
Next, although E911 did provide emergency dispatch with the name and address of the calling party, it did so solely through the use of a nationwide database known as the Automation Location Identification (ALI) database. When 911 is dialed, the calling phone number is used to look up the name and address contained within the ALI database. The call is then routed to the closest public safety answering point. While the ALI is useful, it often does not provide the most accurate results.
Pinpointing location is key
A business with multiple locations, for example, may have deployed an IP-based unified communications platform designed with a single voice gateway to the PSTN for outbound calling -- including 911. If not properly managed, calls to 911 may end up looking like they are coming from a single location as opposed to the actual office from which the call was generated. Thus, emergency services may accidently be dispatched to the wrong location. Moreover, the ALI is updated manually by the local exchange carrier; updates to address locations of the calling phone can often go unnoticed for years.
NG911 standards use a far more accurate method to determine the physical location of the calling party. While it still relies on ALI data, it also automatically taps into supplementary location data that was not previously available. First responders are now more likely to have accurate physical location information -- a critical part of 911 service.