Enhanced 911 (E911) is 911 service that sends the caller's phone number and location to the 911 center along with the call. The call taker has a number to ring back if the line drops and an address to send help to. For business phone systems and VoIP, FCC rules set the standard as a dispatchable location: a validated street address plus the floor, suite, apartment or similar detail needed to find the caller. Devices that move get fallbacks when that isn't technically feasible.
\n","summary":"E911 sends the caller's phone number and location to the 911 center with the call. For business phone systems the standard is a dispatchable location, which the business records for each device, keeps current and tests.","publishedAt":"2026-04-16T16:31:50.28","verifiedAt":"2026-10-09T21:22:20.784","editorialStatus":"APPROVED","lastReviewedAt":"2026-10-10T01:26:42.985","nextReviewDueAt":"2027-01-09T21:22:20.784","templateVersion":"v2","aliases":["What does E911 stand for?","What is E911 service?","What is the difference between 911 and E911?","How does Enhanced 911 work?","What is E911 for VoIP?","What is E911 compliance?","What is a dispatchable location for 911?","What are ANI and ALI in 911?","Is E911 required by law in the United States?","What is the difference between E911 and NG911?"],"confidenceScore":90,"confidenceLabel":"High","canonicalUrl":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"contributorOrganizationProfile":null,"contributorPerson":null,"sections":[{"id":"60db98db-42fd-4c91-b186-9cc2972479e2","sectionKey":"what_happens_on_a_911_call","sectionType":"markdown_section","heading":"What happens when someone dials 911","introMarkdown":"A 911 call picks up two pieces of data on its way to the 911 center. One is a number to call back. Automatic Number Identification, or ANI, identifies the calling party, and the FCC's definitions say it may be used as the callback number. The other is the location. Automatic Location Information, or ALI, tells emergency services where the caller is. For internet-based phone service, [47 CFR 9.11](https://www.law.cornell.edu/cfr/text/47/9.11) requires that location to be available to the 911 center from or through the ALI database.\n\nThe location also steers the call. The same rule sends a VoIP 911 call to the 911 center that serves the caller's dispatchable location, so a stale address can put the call in front of dispatchers in the wrong jurisdiction.\n\nThat location comes from one of two places: a record stored for the phone or number, or the network the device is connected to when it dials. A stored record shows whatever was last typed into it. A desk phone with a manually entered record that moved from the second floor to the fifth in March keeps reporting the second floor until someone updates the entry.\n\nSome devices can't be located automatically, such as a softphone on a home network. For that kind of non-fixed service, the rule lets the provider use a Registered Location the user supplied, use alternative location information, or route the call to a national emergency call center.\n\n[47 CFR 9.16](https://www.law.cornell.edu/cfr/text/47/9.16), the rule that carries out Kari's Law, covers multi-line phone systems manufactured, imported, first sold or leased, or installed after February 16, 2020. People using a covered system must be able to reach 911 \"without dialing any additional digit, code, prefix, or post-fix.\" That means no 9 for an outside line. Where the system can be configured for it without hardware or software changes, it also has to alert a central location, on site or elsewhere, where someone is likely to see or hear the alert. The notice says a 911 call was made, and it includes a callback number and the caller's location where those are technically feasible to provide.","introHtml":"A 911 call picks up two pieces of data on its way to the 911 center. One is a number to call back. Automatic Number Identification, or ANI, identifies the calling party, and the FCC's definitions say it may be used as the callback number. The other is the location. Automatic Location Information, or ALI, tells emergency services where the caller is. For internet-based phone service, 47 CFR 9.11 requires that location to be available to the 911 center from or through the ALI database.
\nThe location also steers the call. The same rule sends a VoIP 911 call to the 911 center that serves the caller's dispatchable location, so a stale address can put the call in front of dispatchers in the wrong jurisdiction.
\nThat location comes from one of two places: a record stored for the phone or number, or the network the device is connected to when it dials. A stored record shows whatever was last typed into it. A desk phone with a manually entered record that moved from the second floor to the fifth in March keeps reporting the second floor until someone updates the entry.
\nSome devices can't be located automatically, such as a softphone on a home network. For that kind of non-fixed service, the rule lets the provider use a Registered Location the user supplied, use alternative location information, or route the call to a national emergency call center.
\n47 CFR 9.16, the rule that carries out Kari's Law, covers multi-line phone systems manufactured, imported, first sold or leased, or installed after February 16, 2020. People using a covered system must be able to reach 911 "without dialing any additional digit, code, prefix, or post-fix." That means no 9 for an outside line. Where the system can be configured for it without hardware or software changes, it also has to alert a central location, on site or elsewhere, where someone is likely to see or hear the alert. The notice says a 911 call was made, and it includes a callback number and the caller's location where those are technically feasible to provide.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":10},{"id":"7c0a4103-2518-4660-a867-cbc1be0df9c2","sectionKey":"rules_for_business_phone_systems","sectionType":"markdown_section","heading":"Which rules cover a business phone system","introMarkdown":"A [cloud PBX service](https://www.answerstack.io/q/what-is-the-difference-between-sip-trunking-and-cloud-pbx) counts as a multi-line telephone system just as a PBX in a wiring closet does, because the FCC's definition names network-based and premises-based systems such as Centrex and VoIP. The [February 16, 2020 cutoff](https://www.fcc.gov/mlts-911-requirements) applies to hosted and on-site systems alike.\n\nSection 9.16 then sets a location duty for each kind of device, and the duty depends on whether the device can move. The FCC [describes a fixed device](https://www.fcc.gov/911-dispatchable-location) as one the user cannot readily move. An automated location is one generated without any action by the caller.\n\nThe same section bars anyone from managing or operating a covered system unless it is configured to convey the required location. The FCC's definitions describe the manager as the entity that distributes lines and assigns telephone numbers after installation. In an office that is usually the IT team or an office manager, so the location records need an owner inside the business after the provider finishes the install. The table below shows what each kind of device owes.","introHtml":"A cloud PBX service counts as a multi-line telephone system just as a PBX in a wiring closet does, because the FCC's definition names network-based and premises-based systems such as Centrex and VoIP. The February 16, 2020 cutoff applies to hosted and on-site systems alike.
\nSection 9.16 then sets a location duty for each kind of device, and the duty depends on whether the device can move. The FCC describes a fixed device as one the user cannot readily move. An automated location is one generated without any action by the caller.
\nThe same section bars anyone from managing or operating a covered system unless it is configured to convey the required location. The FCC's definitions describe the manager as the entity that distributes lines and assigns telephone numbers after installation. In an office that is usually the IT team or an office manager, so the location records need an owner inside the business after the provider finishes the install. The table below shows what each kind of device owes.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":20},{"id":"5216563f-c73b-46b3-9065-7fc8716fd5fe","sectionKey":"location_duty_by_device","sectionType":"table_section","heading":"The location each kind of device has to send","introMarkdown":null,"introHtml":null,"outroMarkdown":null,"outroHtml":null,"contentJson":{"rows":[{"cells":["Desk phone wired to one spot in the office","Automated dispatchable location","January 6, 2021"]},{"cells":["Softphone or Wi-Fi handset that roams around the office","Automated dispatchable location when technically feasible. Otherwise a location the user updates by hand, or alternative location information.","January 6, 2022"]},{"cells":["Laptop or phone used off site, such as a home office","Automated dispatchable location when technically feasible. Otherwise a manual update by the user, or enhanced location information that may be coordinate-based.","January 6, 2022"]}],"columns":["Device","Location owed with a 911 call","In effect since"]},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":30},{"id":"3873cf2c-3a13-4926-a6e5-2bb8e0b87273","sectionKey":"static_and_dynamic_location_records","sectionType":"markdown_section","heading":"Static and dynamic location records","introMarkdown":"Atlantech sells E911 two ways, and [its explanation of the two](https://www.atlantech.net/blog/store-911-location-data-pidf-lo) shows the choice any business has to make. With static E911, one address is assigned to each phone number. It fits a small number of phones in one fixed location where the street address alone finds the caller. The record holds the street address without a floor, suite or room, and someone updates it by hand when a phone moves.\n\nWith dynamic E911, which Atlantech also calls nomadic, the location is configured on each LAN switch and Wi-Fi access point. When a phone connected to that equipment dials 911, the location [travels with the call in PIDF-LO headers](https://www.atlantech.net/blog/nomadic-e911), a standard format for location data. The record can carry a floor, suite or room, and it follows the phone to whichever switch or access point it joins.\n\nDynamic E911 asks more of the network. The equipment has to support PIDF-LO and be configured correctly, the network gateway needs a valid address, and the firewall or NAT device has to pass the headers unaltered. A multi-floor office, or one where softphones and Wi-Fi handsets roam, takes on that work because responders need the floor.","introHtml":"Atlantech sells E911 two ways, and its explanation of the two shows the choice any business has to make. With static E911, one address is assigned to each phone number. It fits a small number of phones in one fixed location where the street address alone finds the caller. The record holds the street address without a floor, suite or room, and someone updates it by hand when a phone moves.
\nWith dynamic E911, which Atlantech also calls nomadic, the location is configured on each LAN switch and Wi-Fi access point. When a phone connected to that equipment dials 911, the location travels with the call in PIDF-LO headers, a standard format for location data. The record can carry a floor, suite or room, and it follows the phone to whichever switch or access point it joins.
\nDynamic E911 asks more of the network. The equipment has to support PIDF-LO and be configured correctly, the network gateway needs a valid address, and the firewall or NAT device has to pass the headers unaltered. A multi-floor office, or one where softphones and Wi-Fi handsets roam, takes on that work because responders need the floor.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":40},{"id":"4703a478-c7a3-4721-ab7d-7e0b70d12ee1","sectionKey":"setup_for_three_floor_hybrid_office","sectionType":"markdown_section","heading":"Setting it up for a three-floor office with hybrid staff","introMarkdown":"Suppose a 60-person firm leases floors two through four of an office building. Staff use Microsoft Teams softphones on laptops, and about a third of them work from home on any given day. The firm buys its calling service from Atlantech and sets up dynamic E911.\n\nIT starts by assigning a floor and an area to every LAN switch and Wi-Fi access point. For Teams, those locations live in Microsoft's Location Information Server, where subnets, switch ports and access points are tied to civic addresses in the Teams Admin Center or PowerShell. Atlantech [provisions the addresses from the customer's data](https://www.atlantech.net/blog/teams-calling-nomadic-e911) and can add places such as a floor, suite or room. At the same stage, the firm confirms with Atlantech that 911 goes out from every extension with no prefix. It also asks which number the 911 center receives when an extension without its own direct number dials 911. A dispatcher uses that number if the call drops, so it should ring somewhere a person will answer.\n\nA laptop at home is off the mapped office network, and Atlantech advises against adding home networks as trusted addresses because an internet provider can change them. What a remote user experiences depends on the Teams calling product. With Direct Routing, a 911 call from outside the corporate network [goes to a 24/7 national emergency call center](https://www.atlantech.net/blog/teams-calling-nomadic-e911), which transfers it to the right 911 center. With Operator Connect, off-premises users [are prompted to confirm their current address](https://www.atlantech.net/faq/microsoft-teams-operator-connect/how-does-operator-connect-handle-emergency-calling-and-911-compliance), and that address is validated and used for routing. Tell remote staff which of the two they'll meet, so it doesn't surprise them in an emergency.\n\nThen the firm turns on notification. Atlantech's [E911 notification](https://www.atlantech.net/blog/e911-notification-feature) comes with its voice service at no extra charge. The firm emails support@atlantech.net, asks to enable it and names the address that should receive alerts. It accepts a single address, and that address can be a distribution list.\n\nTesting is done by dialing 933. Atlantech describes a 933 call as a test that the correct physical address reaches the 911 center. Place one from a phone on each floor and one from a softphone on Wi-Fi, and compare the address the test returns with where the caller is sitting. Each 933 call also triggers the notification email, so the same test shows whether the alert reaches a person and what it contains. Atlantech's Operator Connect onboarding includes guided E911 validation and test access to a 911 center.\n\nAfter launch, the work is keeping the records current. A softphone that changes floors reports the new floor as long as the access point it joins is mapped. A new or relocated switch or access point needs its location entered before anyone uses it, followed by another 933 test. Atlantech recommends testing 933 at least once a year, and a network change is a reason to test sooner.\n\nThe firm names one person to update location records and run the 933 test after each move.","introHtml":"Suppose a 60-person firm leases floors two through four of an office building. Staff use Microsoft Teams softphones on laptops, and about a third of them work from home on any given day. The firm buys its calling service from Atlantech and sets up dynamic E911.
\nIT starts by assigning a floor and an area to every LAN switch and Wi-Fi access point. For Teams, those locations live in Microsoft's Location Information Server, where subnets, switch ports and access points are tied to civic addresses in the Teams Admin Center or PowerShell. Atlantech provisions the addresses from the customer's data and can add places such as a floor, suite or room. At the same stage, the firm confirms with Atlantech that 911 goes out from every extension with no prefix. It also asks which number the 911 center receives when an extension without its own direct number dials 911. A dispatcher uses that number if the call drops, so it should ring somewhere a person will answer.
\nA laptop at home is off the mapped office network, and Atlantech advises against adding home networks as trusted addresses because an internet provider can change them. What a remote user experiences depends on the Teams calling product. With Direct Routing, a 911 call from outside the corporate network goes to a 24/7 national emergency call center, which transfers it to the right 911 center. With Operator Connect, off-premises users are prompted to confirm their current address, and that address is validated and used for routing. Tell remote staff which of the two they'll meet, so it doesn't surprise them in an emergency.
\nThen the firm turns on notification. Atlantech's E911 notification comes with its voice service at no extra charge. The firm emails support@atlantech.net, asks to enable it and names the address that should receive alerts. It accepts a single address, and that address can be a distribution list.
\nTesting is done by dialing 933. Atlantech describes a 933 call as a test that the correct physical address reaches the 911 center. Place one from a phone on each floor and one from a softphone on Wi-Fi, and compare the address the test returns with where the caller is sitting. Each 933 call also triggers the notification email, so the same test shows whether the alert reaches a person and what it contains. Atlantech's Operator Connect onboarding includes guided E911 validation and test access to a 911 center.
\nAfter launch, the work is keeping the records current. A softphone that changes floors reports the new floor as long as the access point it joins is mapped. A new or relocated switch or access point needs its location entered before anyone uses it, followed by another 933 test. Atlantech recommends testing 933 at least once a year, and a network change is a reason to test sooner.
\nThe firm names one person to update location records and run the 933 test after each move.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":50}],"citations":[],"revisions":[{"revisedAt":"2026-07-20T16:31:50.28+00:00","versionLabel":"Originally published","note":"","reviewedBy":null}],"relatedAnswers":[{"id":"b03c7fc2-b75b-407b-94c2-28d16792a61d","slug":"how-do-i-register-a-voip-phone-for-911","question":"How do I register a VoIP phone for 911?","publishedAt":"2026-07-20T16:31:58.611","confidenceScore":85,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"emergency-calling","label":"Emergency Calling","description":"911, E911, and NG911 for VoIP and SIP: registration, location accuracy, and call routing.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"Registering a VoIP phone for 911 means giving your provider the street address where the phone is used, plus the suite or floor if responders would need it, so the provider can tie that location to the phone. Atlantech Online documents two options: a static address per phone number for a desk phone, and location taken from switches and access points for phones that move inside a building. It also documents a support-ticket route for corrections, and a 933 call that reads the registered address back.","url":"/q/how-do-i-register-a-voip-phone-for-911"},{"id":"d646fe66-5b68-41ac-9f7a-3a885825df52","slug":"what-is-next-generation-911-ng911-and-how-is-it-different-from-e911","question":"What is Next Generation 911 (NG911), and how is it different from E911?","publishedAt":"2026-06-17T16:31:53.296","confidenceScore":92,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"emergency-calling","label":"Emergency Calling","description":"911, E911, and NG911 for VoIP and SIP: registration, location accuracy, and call routing.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"NG911 is an IP-based system for receiving, routing and delivering 911 calls. It replaces the circuit-switched network behind legacy E911, which delivers a voice call with the caller's number and location. The functions carry over and the architecture changes: NG911 routes on a location carried inside the call. Each 911 authority moves to it when its own network is ready.","url":"/q/what-is-next-generation-911-ng911-and-how-is-it-different-from-e911"},{"id":"eec6f088-b596-4007-a107-81939f09ee74","slug":"what-is-a-psap-public-safety-answering-point","question":"What is a PSAP (Public Safety Answering Point)?","publishedAt":"2026-05-12T16:31:56.115","confidenceScore":93,"confidenceLabel":"High","industry":{"id":"ff619d7c-d7d7-485e-a05a-53fba07f33ed","slug":"telecommunications","label":"Telecommunications","description":"Business voice, fiber, UCaaS, and network services"},"topic":{"slug":"emergency-calling","label":"Emergency Calling","description":"911, E911, and NG911 for VoIP and SIP: registration, location accuracy, and call routing.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"A public safety answering point, or PSAP, is the 911 center designated to receive emergency calls and route them to emergency services personnel. A primary PSAP gets the call first, and a secondary PSAP takes calls transferred from a primary. The caller's location decides which PSAP a call reaches, which is why the address a VoIP provider holds for a phone matters at the PSAP's end.","url":"/q/what-is-a-psap-public-safety-answering-point"}],"contributorStats":{"verifiedAnswers":149,"openDisputes":0},"schemaJson":{"@context":"https://schema.org","@type":"Question","name":"What is Enhanced 911 (E911)?","text":"What is Enhanced 911 (E911)?","url":"https://www.answerstack.io/q/what-is-enhanced-911-e911","answerCount":1,"datePublished":"2026-04-16T16:31:50.28","about":[{"@type":"Thing","name":"Emergency Calling"},{"@type":"Thing","name":"Telecommunications"}],"acceptedAnswer":{"@type":"Answer","text":"Enhanced 911 (E911) is 911 service that sends the caller's phone number and location to the 911 center along with the call. The call taker has a number to ring back if the line drops and an address to send help to. For business phone systems and VoIP, FCC rules set the standard as a dispatchable location: a validated street address plus the floor, suite, apartment or similar detail needed to find the caller. Devices that move get fallbacks when that isn't technically feasible.","url":"https://www.answerstack.io/q/what-is-enhanced-911-e911","upvoteCount":0,"datePublished":"2026-04-16T16:31:50.28","dateModified":"2026-10-09T21:22:20.784","citation":[]}}}