2.3 MLTS Compliance: Kari's Law & RAY BAUM'S Act
Key Takeaways
- Multi-Line Telephone Systems (MLTS) consolidate enterprise endpoints onto shared external trunk groups, creating the catastrophic 'billing address trap' where off-premises 9-1-1 calls default to the main corporate headquarters address.
- Station Level Detail (SLD) and Private Switch ALI (PS-ALI) resolve enterprise location by mapping internal extensions to Emergency Response Locations (ERLs) and assigning 10-digit Emergency Location Identification Numbers (ELINs), supported by Direct Station Dialing (DSD) for PSAP callbacks.
- Dynamic location tracking in enterprise IP telephony utilizes Layer 2 switch port discovery (LLDP-MED, ANSI/TIA-1057; 802.1X; SNMP wiremapping), Layer 3 subnet ranges, enterprise Wi-Fi BSSID mapping, and HELD protocol (RFC 5985) captive portals for remote teleworkers.
- Kari's Law (codified at 47 U.S.C. § 623 and 47 CFR § 9.16; effective February 16, 2020) mandates direct 9-1-1 dialing without prefix digits (e.g., no dialing '9') and simultaneous notification to a central on-site/off-site monitoring point without delaying call routing.
- Section 506 of the RAY BAUM'S Act (47 CFR Part 9) mandates that all MLTS 9-1-1 calls convey a validated 'Dispatchable Location' (street address plus room, suite, or floor), enforcing phased compliance on January 6, 2021 (fixed devices) and January 6, 2022 (non-fixed and remote devices).
2.3 MLTS Compliance: Kari's Law & RAY BAUM'S Act
Quick Answer: Kari's Law (codified at 47 U.S.C. § 623; FCC rules effective February 16, 2020) mandates that all multi-line telephone systems (MLTS) allow direct dialing of 9-1-1 without dialing an outside access digit (such as '9') and provide simultaneous notification to an on-site or off-site monitoring location whenever 9-1-1 is dialed without delaying call completion. Section 506 of the RAY BAUM'S Act complements this by requiring that every 9-1-1 call from MLTS and VoIP devices convey a validated "Dispatchable Location"—defined as the caller's street address plus granular sub-location details (building, floor, suite, or room) necessary to locate the victim rapidly without searching. Compliance took effect January 6, 2021 for on-premises fixed devices, and January 6, 2022 for on-premises non-fixed and off-premises devices.
In public safety telecommunications, the term Multi-Line Telephone System (MLTS) encompasses any private enterprise switching system that serves multiple telephone endpoints across an organization. Typical deployments include corporate campuses, multi-story commercial office towers, healthcare facilities, university campuses, hotels, and municipal government buildings. While MLTS platforms provide substantial operational and economic efficiencies for business communications, they historically represented the single greatest point of failure in emergency caller location and call routing.
1. The Enterprise Telephony Spectrum & The Billing Address Trap
To understand MLTS location engineering, the ENP must evaluate the primary enterprise telephony architectures:
- Centrex: Central Office Exchange Service provided by the Local Exchange Carrier (LEC). Enterprise extensions are switched directly at the carrier central office. Historically, Centrex maintained an individual ALI record for every desk phone, providing direct station-level location.
- Traditional TDM PBX: Private Branch Exchange hardware owned by the customer, connected to the PSTN via shared T1 Primary Rate Interface (PRI) circuits. Rather than purchasing 1,000 lines for 1,000 employees, the business purchases 46 to 92 trunk channels (two to four PRIs), capitalizing on statistical multiplexing.
- IP-PBX: Packet-switched on-premises servers (e.g., Cisco Unified Communications Manager, Avaya Aura) routing voice internally via Session Initiation Protocol (SIP, RFC 3261) across enterprise LANs, connecting to the PSTN via centralized SIP trunks.
- Cloud UCaaS: Unified Communications as a Service (e.g., Microsoft Teams Phone, Zoom Phone, Cisco Webex Calling). The PBX engine resides in multi-tenant cloud data centers, serving nomadic softphones running on laptops, mobile phones, and desk IP devices over public broadband or corporate SD-WAN.
The Fundamental MLTS Dilemma: Centralized Trunking
The financial efficiency of MLTS stems from consolidating outbound voice traffic onto shared trunk groups. However, this creates a catastrophic failure mode known as the billing address trap:
+-------------------------------------------------------------------------+
| THE CLASSIC MLTS BILLING ADDRESS TRAP |
+-------------------------------------------------------------------------+
| SATELLITE BRANCH (Building 4, Floor 3) CORPORATE HEADQUARTERS |
| Employee dials 9-1-1 on ext 4412 Central Data Center |
| │ │ |
| ▼ (Corporate WAN / SD-WAN) │ |
| [IP Phone Ext 4412] ───────────────────────────► [Central IP-PBX] |
| │ |
| PBX transmits default |
| Corporate BTN only |
| ▼ |
| [PSTN / PRI Trunks] |
| │ |
| ▼ |
| [9-1-1 Selective Router] |
| │ |
| ▼ |
| [ALI Database Record] |
| Shows: Corporate HQ |
| 100 Corporate Parkway |
| │ |
| ▼ |
| [PSAP Dispatches to HQ] |
| Responders sent 40 miles|
| away from dying caller |
+-------------------------------------------------------------------------+
When an employee in a satellite branch office 40 miles away dials 9-1-1, a legacy PBX without location logic transmits the default master Billing Telephone Number (BTN) associated with the central trunk group. The E9-1-1 Selective Router matches the BTN against the carrier ALI database and directs the call to the PSAP serving corporate headquarters. Emergency responders are dispatched to the corporate headquarters building while the victim is dying across county lines.
2. Station Level Detail (SLD) & Private Switch ALI (PS-ALI)
To eliminate the billing address trap, public safety and telecommunications engineers developed Station Level Detail (SLD), operationalized through Private Switch ALI (PS-ALI). PS-ALI decouples the enterprise extension numbering plan from the public 9-1-1 network using two foundational building blocks:
- Emergency Response Location (ERL): An ERL is a defined, discrete geographic zone within an enterprise facility that emergency personnel can locate rapidly without searching. Many state MLTS laws and NENA's model MLTS legislation use a benchmark of no more than 7,000 square feet per ERL, typically confined to a single floor of a multi-story facility; the exact thresholds vary by state.
- Emergency Location Identification Number (ELIN): An ELIN is a valid, routable 10-digit North American Numbering Plan (NANP) telephone number. The enterprise provisions a block of Direct Inward Dialing (DID) numbers to serve as ELINs. Each ELIN is provisioned in the regional 9-1-1 Database Management System (DBMS) with a specific, validated ERL address (e.g., "ELIN 214-555-0199 = 800 Tech Boulevard, Tower 2, Floor 4, West Wing").
PS-ALI Call Execution & Direct Station Dialing (DSD)
- Outbound Routing: When an extension in an ERL dials 9-1-1, the PBX dynamically substitutes the internal extension with the associated ELIN in the outbound Calling Party Number (CPN) signaling field. The Selective Router routes the call to the correct local PSAP based on the ELIN, and the PSAP retrieves the granular ERL record from the ALI database.
- Inbound Direct Station Dialing (DSD): If the 9-1-1 call prematurely disconnects, the telecommunicator immediately calls the number displayed on the ALI console—which is the ELIN. The enterprise PBX must be configured with Direct Station Dialing (DSD) or an automated call-back holding table. When an incoming call hits that ELIN within an operational window (typically 30 to 60 minutes), the PBX must ring the specific internal extension that placed the emergency call, bypassing receptionist switchboards and automated attendants.
- Database Synchronization: Extension-to-ERL mappings are uploaded to the 9-1-1 database provider's PS-ALI service using NENA-defined data exchange record formats, usually through a secure file transfer or web portal, so the ALI record matches the ELIN the switch sends.
3. Dynamic IP Location Tracking: Layer 2 & Layer 3 Wiremapping
In legacy TDM PBX systems, phones were physically wired to fixed punch blocks connected to wall jacks. In modern enterprise VoIP and IP-PBX environments, physical hardwiring no longer exists. An employee can unplug their VoIP desk phone from Floor 2, plug into an Ethernet jack on Floor 8, and retain their extension number. If an enterprise relies on static extension tables, the E9-1-1 location record becomes instantly invalid.
To manage device mobility, modern enterprise emergency management engines (e.g., Cisco Emergency Responder, RedSky Horizon Mobility, Intrado Emergency Gateway) execute automated network wiremapping:
+-------------------------------------------------------------------------+
| DYNAMIC LAYER 2 / LLDP-MED LOCATION MAPPING |
+-------------------------------------------------------------------------+
| |
| [IP Desk Phone] ◄────── LLDP-MED (Layer 2) ─────► [Managed Switch] |
| MAC: 00:1A:2B:3C:4D:5E IP: 10.10.40.15 |
| Sends Endpoint Metadata Port: Gi1/0/22 |
| │ |
| ▼ (SNMP/802.1X)
| +-----------------------+ |
| | Enterprise 9-1-1 Mgr | |
| +-----------------------+ |
| │ |
| ▼ |
| [Wiremap Database] |
| Switch 10.10.40.15, |
| Port Gi1/0/22 = Jack 314 |
| = Bldg 2, Fl 3, Rm 314 |
| = Assigns ELIN to Phone |
+-------------------------------------------------------------------------+
Layer 2 Tracking: LLDP-MED & 802.1X Port Binding
The most precise method for tracking fixed and semi-fixed IP phones on an enterprise LAN is at Layer 2 (Data Link Layer):
- LLDP-MED (ANSI/TIA-1057): Link Layer Discovery Protocol - Media Endpoint Discovery operates between network switches and IP phones. During device boot or link connection, LLDP-MED frames exchange chassis IDs, port component IDs, and VLAN attributes.
- Cisco Discovery Protocol (CDP): Performs equivalent neighbor-discovery functions on Cisco-native network switches.
- SNMP Polling & 802.1X Tracking: The enterprise emergency management server polls managed switches via Simple Network Management Protocol (SNMP) or monitors IEEE 802.1X authentication events. The server detects that MAC address
00:1A:2B:3C:4D:5Ehas connected to Switch10.10.40.15, PortGigabitEthernet 1/0/22. - The Wiremap Database: Network engineers maintain an audited wiremap linking physical switch ports to patch panels and architectural wall jacks. The system automatically determines that Port
Gi1/0/22corresponds to JackJ-314in Building 2, Floor 3, Room 314, dynamically binding the corresponding ELIN to the phone in real time.
Layer 3 Tracking: Subnet and CIDR Range Mapping
In environments with unmanaged edge switches or routed branch locations, systems utilize Layer 3 (Network Layer) tracking. The network team aligns IPv4/IPv6 subnets with physical boundaries (e.g., subnet 172.24.12.0/24 serves Building 1, Floor 2, while 172.24.13.0/24 serves Floor 3). The emergency management server maps any IP address falling within that Classless Inter-Domain Routing (CIDR) block to that floor's ERL.
Nomadic Wi-Fi Clients & Remote Workers
- Enterprise Wi-Fi (BSSID Mapping): Softphones running on campus laptops detect the Basic Service Set Identifier (BSSID) of the ceiling-mounted Wi-Fi access point (AP) to which they are associated. The tracking server maps the AP's surveyed physical location to an ERL.
- Remote Teleworkers & HELD (RFC 5985): For employees working from home or hotels using cloud UCaaS softphones over VPN or public internet, the device queries a Location Information Server (LIS) using HTTP Enabled Location Delivery (HELD, RFC 5985). If the client detects it is on an external, untrusted network, the softphone enforces a captive self-provisioning prompt, requiring the employee to input and validate their current physical street address before placing external calls.
4. Kari's Law: Statutory Genesis, Mandates & FCC Part 9
On December 1, 2013, Kari Hunt was attacked and murdered by her estranged husband in a motel room in Marshall, Texas. Her 9-year-old daughter, having been taught in school to call 9-1-1 in an emergency, ran to the motel room phone and dialed 9-1-1. Four successive times, the child dialed 9-1-1. Four times, the call failed to connect. Kari Hunt died from her injuries before emergency personnel were alerted.
The motel's MLTS required guests to dial "9" to access an outside line before dialing external telephone numbers. Because the child dialed "9-1-1" instead of "9-9-1-1," the PBX treated the digits as an invalid internal extension string and dropped the calls. Furthermore, neither the motel front desk nor any security staff was alerted to the assault occurring inside the room.
Following tireless advocacy by Kari's father, Hank Hunt, and public safety organizations, Congress passed the Kari's Law Act of 2017 (Public Law 115-127), enacted February 16, 2018, and codified at 47 U.S.C. § 623. The FCC adopted formal implementing regulations in FCC Report and Order 19-76, codifying them into 47 CFR Part 9 with an effective compliance date of February 16, 2020.
Mandatory Operational Requirements Under Kari's Law
- Direct 9-1-1 Dialing (No Prefix Required): Any entity that manufactures, imports, sells, leases, installs, manages, or operates an MLTS must ensure that the system is configured to initiate a 9-1-1 call directly, without dialing any prefix, trunk code, access code (such as '9' or '8'), or key combination.
- Dual-Dialing Allowance: Systems may also support historical dialing strings (e.g., "9-9-1-1") as secondary aliases, but direct 9-1-1 dialing can never be disabled.
- Simultaneous Internal Notification: When an MLTS initiates an outbound 9-1-1 call, the system must generate a simultaneous notification to a central on-site or off-site location where someone is likely to see or hear it (e.g., a 24/7 security operations center, front desk, administrative office, or security guard desk).
- Strict Non-Interference Mandate: The notification mechanism must NEVER delay, block, or intercept the outbound 9-1-1 call to public safety. The 9-1-1 call must route to the PSAP concurrently with, or prior to, the dispatch of the internal notification.
- Mandatory Notification Payload: The notification must include, at a minimum: (1) the fact that a 9-1-1 call has been placed; (2) a valid callback number (ELIN or direct extension); and (3) the location information the MLTS conveys to the PSAP. The callback number and location may be omitted only where including them is technically infeasible.
- Delivery Formats: Notifications may be delivered via automated visual screen pops, audible chimes, automated SMS, email, or synthesized voice alerts over security radio talkgroups.
Applicability Date: No Retrofit Mandate
Kari's Law obligations apply to MLTS that are manufactured, imported, offered for first sale or lease, first sold or leased, or installed after February 16, 2020. The FCC rules do not require organizations to retrofit systems installed before that date, although many upgrade voluntarily and some state laws impose their own requirements. Once a covered system is in place, direct dialing is required and on-site notification must be provided where technically feasible, without delaying the 9-1-1 call.
5. RAY BAUM'S Act Section 506: The "Dispatchable Location" Mandate
While Kari's Law ensured calls could be dialed directly and alerted internal staff, it did not dictate the level of location detail transmitted to the PSAP. That requirement was enacted under Section 506 of the RAY BAUM'S Act (named in honor of Ray Baum, former staff director of the House Energy and Commerce Committee; enacted as part of the Consolidated Appropriations Act of 2018, Public Law 115-141; codified across 47 CFR Part 9).
The Statutory Definition of Dispatchable Location
Under 47 CFR § 9.3, the FCC legally defines a Dispatchable Location as:
"A location delivered to the PSAP with a 911 call that consists of the validated street address of the calling party, plus additional information such as suite, apartment or similar information necessary to adequately identify the location of the calling party, except for Commercial Mobile Radio Service providers, which shall convey the location information required by subpart C of this part."
This legal standard establishes two mandatory components:
- Validated Street Address: The civic address should be validated against authoritative 9-1-1 address data (the MSAG in legacy E9-1-1 or the Location Validation Function in NG9-1-1). An unvalidated billing or mailing address does not meet the rule.
- Sub-Address Granularity: A street address alone is NOT compliant for an enterprise facility. For a corporate campus or multi-story office building, the record must include specific sub-location attributes: Building ID (e.g., Building C), Floor (e.g., 4th Floor), and Suite/Room (e.g., Suite 420, Office 422).
The Operational "Searching" Test
The operational objective underlying RAY BAUM'S Act is that first responders arriving at a complex commercial, educational, or healthcare facility must be capable of navigating directly to the victim without stopping to search corridors, knocking on random doors, or wandering sprawling warehouse aisles.
Alternative Location Solutions
If an enterprise or service provider demonstrates that delivering an automated civic dispatchable location is technically infeasible (e.g., certain nomadic softphones or off-premises mobile clients), it must deliver an alternative location:
- In-building coordinate-based (geodetic $x, y, z$) positioning meeting FCC accuracy standards; or
- A user-provided, validated physical location acquired via real-time captive self-provisioning portals.
6. Phased Implementation Timeline & Device Scope
The FCC established a two-phased compliance schedule under 47 CFR Part 9:
+-------------------------------------------------------------------------+
| RAY BAUM'S ACT SECTION 506 TIMELINE |
+-------------------------------------------------------------------------+
| [FEBRUARY 16, 2020] |
| Kari's Law Effective: Direct Dialing & Simultaneous Notification |
| |
| [JANUARY 6, 2021] |
| RAY BAUM'S ACT - PHASE 1: ON-PREMISES FIXED DEVICES |
| - Wired IP desk phones, analog desk extensions, fixed conference units |
| - Mandatory automated dispatchable location (Address + Sub-Location) |
| |
| [JANUARY 6, 2022] |
| RAY BAUM'S ACT - PHASE 2: NON-FIXED & OFF-PREMISES DEVICES |
| - On-Premises Non-Fixed: Campus Wi-Fi/DECT handsets, softphones on |
| laptops moving across corporate WLAN |
| - Off-Premises Non-Fixed: Remote teleworkers, home office UCaaS soft- |
| phones, traveling personnel on cellular VPN |
| - Mandatory dispatchable location or validated alternative location |
+-------------------------------------------------------------------------+
- Phase 1 (January 6, 2021) — On-Premises Fixed Devices: Applies to stationary endpoints whose physical location does not routinely change: hardwired desktop IP phones, analog terminal adapter (ATA) extensions, and dedicated conference room phones. Automated dispatchable location is mandatory.
- Phase 2 (January 6, 2022) — On-Premises Non-Fixed & Off-Premises Devices: Applies to mobile enterprise devices (campus Wi-Fi/DECT handsets, softphones running on laptops roaming an office) and remote teleworkers working from home offices or hotel rooms. Requires automated dispatchable location, geodetic coordinates, or user-validated captive portal locations.
7. Legal Liability, FCC Enforcement & PSAP Operational Integration
Compliance with Kari's Law and RAY BAUM'S Act is an active federal mandate with severe regulatory, financial, and operational implications:
Regulatory Enforcement & Civil Liability
- FCC Enforcement: The FCC can enforce Kari's Law and the Section 506 rules with its ordinary Communications Act tools, including Notices of Apparent Liability (NAL) and monetary forfeitures.
- Civil Liability Exposure: If a non-compliant system delays a 9-1-1 call or sends responders to the wrong place, the enterprise can face negligence claims under state law.
- Emergency Planning: Employers should fold MLTS 9-1-1 configuration, testing, and employee instructions into their workplace emergency action plans.
Supply Chain Accountability
- Manufacturers and Vendors: Prohibited from manufacturing, importing, selling, or leasing MLTS platforms that do not support direct dialing and notification capabilities out of the box.
- Installers and Systems Integrators: Legally required to program and verify direct dialing and notification prior to handing the system over to the customer.
- Enterprise System Operators: Bear ongoing legal responsibility for maintaining accurate station-to-ERL wiremaps, verifying notification routing, and provisioning new extensions.
PSAP / ECC Operational Workflows
For telecommunicators and dispatch supervisors, Kari's Law and RAY BAUM'S Act fundamentally enhance emergency response protocols:
- Sub-Location Data Parsing: CAD and CHE systems ingest granular sub-location strings (e.g., "West Tower, Floor 7, Suite 740, Cubicle 7412"). Telecommunicators must immediately relay the full sub-location string over the radio and via Mobile Data Terminals (MDTs) to responding field units, eliminating staging delays at main building entrances.
- Security Coordination: When Kari's Law internal notifications trigger, building security guards or facilities managers are alerted concurrently with public safety. In many cases, security personnel call 9-1-1 to provide real-time updates. Telecommunicators must actively cross-reference incoming security calls with the primary 9-1-1 incident in CAD.
- Facility Access & Staging: Telecommunicators can direct on-site security personnel to unlock exterior security gates, hold express elevators at the ground floor lobby, disarm access turnstiles, and station escorts at the main entrance to guide paramedics directly to the patient.
Under Kari's Law (codified at 47 U.S.C. § 623 and 47 CFR § 9.16), which operational requirement applies to a multi-line telephone system (MLTS) manufactured, sold, leased, or installed after February 16, 2020?
Under Section 506 of the RAY BAUM'S Act and FCC Part 9 regulations, what is the precise legal definition of a 'Dispatchable Location' for MLTS 9-1-1 calls?
What was the critical compliance deadline established by the FCC under RAY BAUM'S Act Section 506 for MLTS on-premises non-fixed devices (such as softphones and campus Wi-Fi handsets) and off-premises / remote devices to deliver automated dispatchable location?