Public Safety Answering Points (PSAPs)

A Public Safety Answering Point (PSAP) is the call center that receives 911 emergency calls and dispatches the appropriate emergency response — police, fire, or emergency medical services. When you dial 911, your call is routed to the PSAP responsible for the geographic area where the call originates.

Legacy 911 routing was based on the telephone number of the caller. The selective router looked up the caller's number in a database (the Master Street Address Guide, or MSAG) and routed the call to the appropriate PSAP. This approach works for landlines tied to a fixed address, but it has serious limitations for cellular and IP-based calls.

NG911 modernizes this architecture with an IP-based Emergency Services IP network (ESInet). Calls are routed as SIP sessions, and the routing logic can consider the caller's actual location (delivered by the device or network) rather than relying solely on a database lookup. NG911 also supports text, video, and data — not just voice.

For organizations operating life-safety systems, the PSAP relationship matters because emergency calls from elevators, fire panels, and emergency phones must reach the correct PSAP with accurate location data. NG911-ready platforms like True911 deliver richer location information and integrate with the next-generation routing infrastructure.