E911 (Enhanced 911) is 911 plus your location: the network delivers your callback number and your registered street address to the dispatch center that answers the call. On a landline, location comes free — the phone company knows where the copper terminates. On VoIP, nothing in the network knows where an IP endpoint physically sits; a SIP trunk registering from your Dallas office looks identical to the same trunk registering from a Denver hotel room. That is why 911 for VoIP is built on registration: you tell your provider where each number lives, and that Registered Location is what routes the call and what the dispatcher sees.
A stale or missing address can send a 911 call to a dispatch center nowhere near the emergency, and the FCC actively enforces the three rule sets that govern VoIP 911. If you run SIP trunks, a PBX, or a multi-site phone system, this guide covers how E911 works, which rules apply to you, and the checklist to run at turn-up. SIPNEX is an FCC-licensed carrier — we write about 911 from inside the same regulatory framework we operate under.
E911 vs 911: what the “E” adds
Basic 911 is a dialing shortcut. The call reaches a public safety answering point (PSAP) — the dispatch center that answers emergency calls — but the dispatcher starts with nothing and must ask where you are and how to call you back. If the caller cannot speak, there is no address to send help to.
E911 adds two pieces of data that ride with the call:
- Callback number. The dispatcher sees a valid number to redial if the call disconnects.
- Location. The caller’s registered address is delivered alongside the call, and that same address determines which PSAP receives the call in the first place.
The routing half matters as much as the display half. E911 uses your location to select the right PSAP out of thousands, each covering a defined territory. A misrouted call still gets answered — by a dispatch center that cannot dispatch to your county and has to transfer you while the clock runs.
How E911 works on a VoIP call
Your provider collects a physical street address — the Registered Location — and provisions it into the databases the 911 system uses for routing and address display. When someone on your system dials 911, the call routes to the PSAP serving the address on file, which is presented to the dispatcher along with a callback number. The critical word is registered: the 911 network does not discover your location, it looks it up, and the chain is only as accurate as the address on file.
Why nomadic use breaks E911
VoIP is nomadic by design — the same SIP credentials work from the office, from home, from a hotel in another state. The 911 database does not follow the endpoint; it holds whatever address was last registered. Take your desk phone home for a month and dial 911, and the call routes on the office address still on file. The dispatcher sees the office. Responders go to the office.
This is the defining E911 problem for VoIP, and why the rules center on the Registered Location: nomadic users must keep it current whenever they move, and providers must give customers an easy way to update it. The FCC’s consumer guidance on VoIP and 911 service tells end users the same thing — register an accurate address before you need it, update it promptly when it changes.
For a fixed deployment — trunks serving one building — this is a set-and-verify exercise. For softphones and remote agents, it is an ongoing process you own operationally.
E911 requirements: the three regulatory layers
Three federal frameworks govern 911 for VoIP. They stack — a business running a modern phone system typically answers to all three.
Layer 1: the 2005 VoIP E911 order
The FCC’s 2005 order requires interconnected VoIP providers — services that exchange calls with the regular phone network — to deliver 911 calls with a callback number and the caller’s Registered Location to the appropriate emergency call center. Providers must collect a Registered Location before activating service, give customers an easy way to update it, and notify customers of the ways VoIP 911 differs from landline 911. Customers cannot opt out of 911.
What this means for you: the address your provider collects at turn-up is the address emergency services get — it is not paperwork to blow through. Give the real service address for each number, read the E911 limitations notice instead of clicking past it, and know where in your provider’s process the address gets updated, because updating it is on you.
Layer 2: Kari’s Law — direct dialing and notification
Kari’s Law targets multi-line telephone systems (MLTS) — the PBX and hosted systems used in offices, hotels, and campuses. It has two requirements, and compliance has been required since February 16, 2020 for systems manufactured, imported, sold, leased, or installed after that date:
- Direct dialing. A user must be able to dial 911 with no prefix or access code. If your dial plan requires 9 for an outside line, 911 must still complete without the 9.
- On-site notification. When someone dials 911, the system must notify a front desk, security office, or designated contact that a 911 call was placed and from where, if it can do so without a hardware or software upgrade.
What this means for you: open your dial plan today and confirm both 911 and 9911 complete to emergency services. Then point the notification at whoever would meet responders at the door — front desk, security, an ops alert. If you inherited a PBX config from an installer years ago, do not assume either behavior exists. The FCC’s MLTS 911 requirements page covers the details.
Layer 3: RAY BAUM’S Act — dispatchable location
Section 506 of RAY BAUM’S Act requires that a “dispatchable location” be conveyed with 911 calls: the street address plus the detail a responder needs to actually find the caller — apartment, suite, floor, or room. Compliance deadlines have passed: January 6, 2021 for fixed MLTS devices, and January 6, 2022 for non-fixed devices and off-premises use such as softphones and remote workers.
What this means for you: one registered address for a 12-story building no longer cuts it — a responder standing in the lobby with nothing but the street address is the exact failure this rule targets. Fixed desk phones should carry location data down to floor or suite level, and because the non-fixed deadline has passed, softphones and remote endpoints are inside the requirement too.
Who is responsible for what
E911 responsibility splits across three parties. Knowing which obligations are yours is most of the battle.
- The interconnected VoIP provider delivers 911 calls with the callback number and Registered Location to the appropriate PSAP, collects a Registered Location before activation, provides an easy way to update it, and notifies customers of E911 limitations.
- The MLTS operator — the business installing or managing a PBX or hosted phone system — ensures direct 911 dialing with no prefix, configures on-site notification, and provisions dispatchable location detail (floor, suite, room) for the endpoints on the system.
- The end user or account admin registers an accurate address for every number at turn-up, updates the Registered Location on every move, and keeps per-user location data current for nomadic endpoints like softphones.
If you run your own PBX behind SIP trunks, you wear two hats: provider’s customer and MLTS operator. The provider delivers the call; the accuracy of what it carries is determined largely by your configuration. Edge cases — resellers, integrators, multi-tenant buildings — get fact-specific, so confirm your obligations with counsel.
E911 setup checklist for a SIP trunk deployment
Run this at turn-up and at every office move. It slots alongside our broader call center compliance guide if you run outbound operations.
- Register a dispatchable address for every site at turn-up. Not the billing address, not headquarters — the physical address where the endpoints sit.
- Add floor, suite, and unit detail. Street address alone does not meet the dispatchable location standard in multi-floor buildings — provision location data per floor or suite where your system supports it.
- Verify direct dialing. Confirm both
911and9911route to emergency services on every PBX, not just the main one. - Configure on-site notification. Point Kari’s Law notifications at a monitored destination — reception, security, or an ops distribution list — and confirm someone actually receives them.
- Validate the registered record with your carrier. Ask your carrier how to confirm the address on file for each number; never place live 911 test calls without coordinating the method with your provider first.
- Update on every move. Office relocation, new floor, agent going remote — each is a Registered Location update. Make it a line item in your move runbook.
- Brief your staff. Remote workers with softphones need to know 911 routes on a registered address — and who to tell when they relocate.
- Confirm with counsel. These layers apply differently by system type, install date, and configurability — this guide is orientation, not legal advice.
Frequently asked questions
What is E911?
E911 (Enhanced 911) is emergency calling that automatically delivers the caller’s callback number and registered street address to the public safety answering point (PSAP) serving that location. The location routes the call to the correct dispatch center and tells the dispatcher where to send responders even if the caller cannot speak. For VoIP, the location comes from a Registered Location the customer provides — the network cannot detect where an IP endpoint is.
What is the difference between 911 and E911?
Basic 911 connects you to a dispatch center with no data attached — the dispatcher must ask your location and callback number. E911 delivers both automatically and uses your location to route the call to the PSAP that covers your address. On landlines the difference is invisible because the address is tied to the physical line. On VoIP it is the difference between a registered, current address and a dispatcher working blind.
Do I have to register my address for VoIP 911?
Yes. Under the FCC’s 2005 VoIP E911 order, interconnected VoIP providers must collect a Registered Location before activating service, and 911 cannot be opted out of. Keeping it accurate is ongoing: nomadic users must update the Registered Location whenever they move, and providers must give you an easy way to do it. The address you register is the address the dispatcher sees.
What is a dispatchable location?
A dispatchable location is the street address of the caller plus the additional detail a responder needs to find them — apartment, suite, floor, or room number. Section 506 of RAY BAUM’S Act requires it to be conveyed with 911 calls, with compliance dates of January 6, 2021 for fixed MLTS devices and January 6, 2022 for non-fixed and off-premises devices such as softphones and remote workers.
What happens if I move and don’t update my E911 address?
Your 911 calls continue to route on the old Registered Location. The call may reach the PSAP serving your previous address, and the dispatcher sees the outdated address — which can delay response while the call is transferred or your real location is established verbally. It is entirely preventable: update the Registered Location with your provider before placing calls from the new location.
SIPNEX is an FCC-licensed carrier — direct authorization, Form 499 filer, our own STIR/SHAKEN certificate — compliance is the framework we operate inside, not a feature we bolted on. If you are deploying SIP trunking or moving off a legacy system (start with our SIP trunking guide), get 911 right at turn-up instead of retrofitting it. Talk to an operator before turn-up so 911 is handled correctly on your deployment or call (833) 665-2220.
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