Emergencies happen and can’t be avoided. That’s why the ability to make a phone call in an emergency is always crucial. When it comes to making emergency phone calls over VoIP, the difference between ALI and ANI databases is always asked.
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.
Envision a 911 operator looking at a screen with the address of the caller before saying “help is on the way”. In this situation, 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.
Ultimately, it is difficult for regional ALI databases to stay current with nomadic VoIP users, and there is no guarantee that the VoIP caller’s accurate location information will be available in a crisis.
Need more information about emergency calling? Contact V1 VoIP for answers to your ANI, ALI and e911 service questions.