V1 VoIP is committed to offering our VoIP providers, resellers and wholesale agents answers to their questions about emergency phone call information. One question asked often is this:
What is the difference between the ALI and ANI databases and how can they effect emergency response?
The Automatic Number Identification (ANI) is the automatic display at the PSAP of the telephone number associated with the line which called 911. Each telephone number and the physical location to which it corresponds are stored in an Automatic Location Identification (ALI) database, managed by the local exchange carrier.
Imagine you are in a ‘Law and Order’ episode. The 911 operator is looking at the screen, sees the adddress of the caller and says “help is on the way.” In that 911 call, the PSAP uses the ANI to retrieve the caller’s physical address from the ALI database. Additionally, the ANI acts as a callback number should the PSAP lose its connection to the distressed caller. Both ANI and ALI are key capabilities of E911 service.
With traditional E911 service, ALI records are stored in regional ALI databases, and are usually administered by the local exchange carrier (LEC). When a phone’s location changes, the regional ALI database must be revised with new location information which can take up to 48 hours to update.
Due to the capabilities of IP phones, it can be difficult to ensure that the regional ALI is up-to-date. Whereas traditional telephone numbers are static, IP phones can be moved easily, forcing the user to notify a network administrator, who in turn must contact the LEC to update the phone’s location in the regional ALI database. Unfortunately, this process takes time to implement, and may be forgotten entirely by the user.
Additionally, IP phones can relocate to regions served by different ALI databases entirely. A VoIP service provider or enterprise would then need agreements with each LEC to update different regional ALI databases as phones move around the country.