Glossary Compliance
What is E911?
Also called enhanced 911, 911 address, emergency calling, ray baums
E911, or Enhanced 911, is the system that delivers a caller's location to the emergency dispatcher along with the call, so help can be sent without the caller having to state an address. For VoIP services this matters more than it did on fixed lines, because a VoIP number is not tied to a physical place.
Why every number needs a registered address
A copper line ran to one building, so the network already knew where a 911 call came from. A VoIP number can be answered anywhere, so the location has to be supplied and kept current. That is why providers require a validated street address for each number, and why moving an office or a home worker means updating it. This is a legal obligation, not a product feature.
Dispatchable location and desk-level detail
US rules require a "dispatchable location", meaning enough detail to actually find the caller: not just the street address but the floor or suite where that matters. In a large building, sending responders to a lobby is not much use. Separate provisions also require that a caller can reach 911 by dialling it directly, without an outside-line prefix, and that someone on site is notified when a 911 call is made.
Nomadic users are the hard part
A desk phone in a fixed office is straightforward. The difficulty is people who take a softphone home, to a client site, or abroad. The address on file is where responders will be sent, so a home worker whose number still lists head office is a genuine safety problem rather than a paperwork one. Practical mitigations are prompting users to confirm their location when they sign in from somewhere new, and reviewing registered addresses periodically rather than treating them as set once at provisioning.