When you call 9-1-1, the last thing you want is for your call to be routed to the wrong dispatch center. It’s also what public safety aims to prevent, as it ties up resources and delays dispatch while calls are transferred to the appropriate public safety answering point (PSAP). Whether it’s a house fire, medical emergency, or car crash, getting help quickly depends on one thing above all else: location accuracy.
Behind the scenes, 9-1-1 systems for years have relied on the Master Street Address Guide (MSAG) to validate addresses so that calls are sent to the right first responders. However, as technology evolves, address validation is becoming more sophisticated. The Location Validation Function (LVF) provides an improved way to confirm addresses are valid and it’s also a crucial element of the nationwide transition to Next Generation 9-1-1 (NG9-1-1).
In the years before we all carried wireless phones and relied on GPS-enabled devices and apps, PSAPs long relied on the MSAG to help route emergency calls.
The MSAG is essentially a tabular database that lists every valid street name, the range of house numbers on each street (e.g., 100-199 Main Street), and which police, fire, or EMS agency serves that area. So if an address fits within a certain range, a 9-1-1 call would be routed to the corresponding PSAP per the MSAG data.
It worked well for its time, but it has some limitations:
The LVF is an important part of modernizing public safety networks under the NG9-1-1 framework. Instead of working from a tabular, text-based MSAG, the LVF uses Geographic Information System (GIS) data—digital maps filled with address points, road centerlines, and emergency service boundaries.
When a service or system, such as voice over IP (VoIP) or an enterprise multi-line telephone system (MLTS), submits an address, or when a 9-1-1 system needs to verify an address, it gets checked against the LVF to confirm whether the address:
If something doesn’t match, the LVF can flag it instantly — giving technicians or address managers a chance to fix it before an emergency ever occurs.
In legacy environments, routing depends on static MSAG data. But in the NG9-1-1 world, information moves over secure IP networks instead of legacy phone lines and location data is geospatial rather than tabular.
The LVF is one piece of the NG9-1-1 ecosystem, confirming addresses before incidents even happen. Another piece is the Emergency Call Routing Function (ECRF). When a 9-1-1 call is made, the ECRF uses data that has been pre-validated by the LVF to route the call to the most appropriate public safety answering point (PSAP)— even as people call from VoIP phones, smart devices, or vehicles that automatically transmit their location.
Upgrading from MSAG to LVF is more than just modernization — it’s making 9-1-1 more reliable, accurate, and responsive for everyone.
For service providers and enterprises, LVF brings speed and simplicity. Addresses can be checked instantly against authoritative GIS data, so 9-1-1 records are validated and accurate before a call is ever placed. It also makes it easier to meet FCC 9-1-1 regulations, such as RAY BAUM’S Act, which requires a dispatchable location.
For PSAPs, the shift to LVF means a big step forward in accuracy and efficiency. Instead of relying on address ranges, every address is now a precise point on a digital map, which dramatically cuts down on calls being routed to the wrong center. When new streets or housing developments appear, GIS managers or 9-1-1 authorities can make updates directly within the GIS data, validated by the LVF, and utilized by ECRF.
For the public, the benefits are simple but powerful. The LVF helps make sure that every 9-1-1 call is routed directly to the right dispatch center with no transfers or wasted time. It also ensures that coverage extends everywhere, from dense city neighborhoods to new housing developments, rural communities, and tribal lands. The result is greater confidence that when you dial 9-1-1, help will find you fast — exactly where you are.
Everyone in public safety says it, but it will never not be true: in an emergency, every second counts. The move from MSAG to LVF is part of a nationwide effort to bring 9-1-1 into the digital age — one where precise mapping, real-time validation, and next generation technology work together to connect people to help faster.
The next time you see your local agency talking about NG9-1-1 upgrades, know that it’s not just about technology. It’s about building a safer, smarter foundation for every call for help. But behind the scenes, technology is making it happen—and LVF is a key part of advancing the transition to NG9-1-1.
Learn More
NENA i3 Next Generation 9-1-1 Related Standard and Best Practices
NENA Information Document for Location Validation Function Consistency
NENA Standards for the Provisioning and Maintenance of GIS Data to ECRFs and LVFs
FCC Facilitating Implementation of Next Generation 9-1-1 Services