E911 and STIR/SHAKEN for SIP Trunking: The Compliance Checklist (2026)

Quick answer: what a SIP trunk has to get right

Two sets of US rules follow every business phone system onto a SIP trunk. E911: under Kari's Law any multi-line system must let a user dial 911 directly with no prefix and must notify someone on site when it happens, and under RAY BAUM's Act every 911 call must carry a dispatchable location (street address plus floor, suite or room) to the emergency call centre, which means every number that can dial out needs a current address on file with the carrier. STIR/SHAKEN: your outbound calls must be signed with an attestation level by the originating provider, and calls that arrive unsigned or with low attestation are far more likely to be labelled "Scam Likely" or blocked. Both are handled at the boundary between your PBX and the trunk, so choosing a provider that provisions E911 per number and signs calls with full attestation is most of the work.

This article is part of the Signalmash SIP trunking resource series: what SIP trunking is, the best providers in 2026, what it costs, SIP vs VoIP and Teams Direct Routing. Broader context is in US telecom regulations.

E911 on a SIP trunk

What the law requires

• Direct dialling (Kari's Law). 911 must work without dialling 9 or any other prefix first, from every phone on the system.
• Notification (Kari's Law). When someone dials 911, the system must notify a central point (front desk, security, a group email or text) with at least the fact of the call and, where possible, the caller's location.
• Dispatchable location (RAY BAUM's Act). The 911 call must deliver a location precise enough for responders to find the caller: address, and for larger buildings the floor, suite or room. For fixed phones that is the phone's installed location; for softphones and remote workers it has to follow the user.

How it works technically

Traditional 911 routed on the caller's number. On a SIP trunk the carrier keeps an E911 record per number (the registered address) and, when a call to 911 arrives, routes it to the public safety answering point that serves that address and passes the address along. That means three things have to be true: every number that can dial out has an accurate address registered with the trunk provider; when a phone moves, someone updates the record (or the PBX passes a new location dynamically); and the PBX sends 911 calls out of the trunk with the right caller ID, not a generic main number that maps to headquarters while the caller is in a branch office.

Remote and mobile users

This is where most SIP deployments fall short. A softphone on a laptop can dial 911 from a hotel room while its number is registered to the office. The fixes, in order of robustness: register a separate number per remote worker with their home address; use a PBX or platform that supports dynamic location (Teams, several contact-centre platforms and modern PBXs can pass a user-confirmed address per session); or, at minimum, prompt remote users to confirm their location at login and update the carrier record. The trunk provider must be able to accept location updates quickly, ideally through a portal or API rather than a ticket.

The checklist

1. Export every DID on the trunk and confirm each has a registered E911 address with floor or suite where relevant.
2. Test 911 dialling from a sample of phones using the carrier's 933 test service where offered, or by arrangement with the provider; never test by dialling 911 unannounced.
3. Confirm the PBX sends the caller's own DID, not a shared main number, on 911 calls.
4. Configure the Kari's Law notification (email, SMS, screen pop) and test that it fires.
5. Document the process for updating addresses when people or phones move, and assign an owner.
6. For remote workers, decide on per-user numbers or dynamic location, and enforce it.

STIR/SHAKEN on a SIP trunk

What it is

STIR/SHAKEN is the FCC-mandated framework for authenticating caller ID. When a call leaves a voice provider's network, the provider signs it with a digital certificate and an attestation level: A (full) means the provider knows the customer and has verified they are entitled to use the caller ID; B (partial) means the provider knows the customer but has not verified the number; C (gateway) means the call merely entered the network from elsewhere. The terminating carrier checks the signature and feeds the result, along with reputation analytics, into the decision to show the call normally, label it as spam or block it. Providers must also be listed in the FCC's Robocall Mitigation Database; calls from providers that are not listed must be blocked downstream.

Why it matters for your business calls

Attestation does not by itself decide whether a call is labelled, but low attestation makes labelling much more likely, and "Scam Likely" on an outbound sales or appointment call is a conversion problem measured in lost answers. On a SIP trunk the attestation level depends on the provider's relationship with you and with the number: a provider that assigned you the number and verified your identity (KYC) can sign with A; a provider carrying calls for numbers it did not assign, such as ported-in numbers whose ownership it has not verified, may sign B; wholesale hops add C. The practical rules: use numbers assigned to or ported to your trunk provider, complete the provider's KYC, do not spoof caller ID to numbers you do not control, and keep call patterns (short duration, high volume, many unanswered) from looking like a robocaller, because analytics weigh behaviour as heavily as signatures.

Beyond attestation: branded caller ID

Full attestation stops your calls being treated as suspicious; it does not tell the recipient who is calling. That is the job of CNAM (the 15-character name displayed on many phones) and, on carriers that support it, branded calling that shows a logo and call reason. Registering CNAM for every outbound number and enrolling in branded caller ID are the difference between "Portland OR" and "Bright Dental Appointments" on the screen. See CNAM and branded caller ID and why business calls get marked Scam Likely.

The checklist

1. Confirm your trunk provider signs outbound calls and is listed in the Robocall Mitigation Database.
2. Ask which attestation level your calls receive and why; aim for A on every number you own.
3. Port numbers to the trunk rather than spoofing them from another carrier's number range.
4. Register CNAM for every outbound number; enrol in branded caller ID where available.
5. Monitor answer rates per number and rotate or remediate numbers that pick up spam labels; the major carriers and their analytics partners offer remediation channels.
6. Keep outbound behaviour clean: honour Do Not Call lists, avoid bursts of short unanswered calls from one number, and keep calling hours legal.

How Signalmash handles both

On a Signalmash SIP trunk every number is provisioned with an E911 dispatchable-location record during onboarding and can be updated from the portal; 933 testing is available; and outbound calls are signed with STIR/SHAKEN attestation, with full attestation on numbers assigned to or ported to your account after KYC. CNAM registration and branded caller ID are part of the same setup, and the voice engineers in your Slack channel can read the SIP trace when a call is labelled and tell you why.

Ask for an E911 and STIR/SHAKEN review of your numbers before your next port, and we will tell you which numbers are at risk of low attestation or a missing address.

People also ask

Does SIP trunking support E911?

Yes. The trunk provider keeps an E911 address for each phone number and routes 911 calls to the emergency centre serving that address, passing the dispatchable location along. Your responsibility is to keep the address for every number current, send the caller's own number on 911 calls, and handle remote workers with per-user numbers or dynamic location.

What are Kari's Law and RAY BAUM's Act?

Kari's Law requires multi-line telephone systems to allow direct 911 dialling with no prefix and to notify a central point when 911 is dialled. RAY BAUM's Act requires 911 calls to convey a dispatchable location (address plus floor, suite or room where needed) to the emergency call centre. Both apply to businesses in the US regardless of whether they use PRI, SIP trunking or a hosted phone system.

What is STIR/SHAKEN attestation A, B and C?

A (full) means the originating provider knows the customer and has verified their right to use the caller ID; B (partial) means the customer is known but the number is not verified; C (gateway) means the call simply entered the network from another provider. Higher attestation lowers the chance of a call being labelled spam or blocked, though carrier analytics also weigh call behaviour.

Why do my business calls show as Scam Likely?

Usually a combination of low STIR/SHAKEN attestation, missing CNAM, and call patterns that look automated: many short outbound calls from one number, low answer rates, or caller ID spoofed from a number your provider did not assign. Fixes are full attestation on numbers you own, CNAM and branded caller ID registration, and remediation with the carriers' analytics partners.

Can a SIP trunk provider give my calls full attestation?

Yes, when the provider has verified your identity and the number is assigned to or ported to your account with them, so they can attest that you are entitled to use it. Numbers spoofed from another carrier's range, or routed through wholesale hops, typically receive B or C attestation.