Multi-Line Telephone System & Private Branch Exchange

Government and public safety agencies have gone to great lengths to ensure consumers have 9-1-1 service available to them through traditional landline, wireless and voice-over IP (VoIP) services. However, everyday millions of Americans, primarily at their place of employment, utilize multi-line telephone systems (MLTS) that do not offer effective 9-1-1 service.

Most MLTS/PBX systems enable the digits 9-1-1 to be dialed and routed to a Public Safety Answering Point (PSAP)(?). However, the vast majority of these systems do not provide granular location information with the 9-1-1 call to enable emergency responders to know the actual location of the emergency.  In many instances a call from the 12th floor of a large office building may only provide the street address of the building.  If the caller is unable to provide his or her location and no one else is available to provide assistance, such a lack of location information can prove fatal.

Fortunately, there are technical solutions to this challenge that are currently being offered by numerous service providers. Still, only sixteen states have enacted statutes and regulations requiring Enhanced 9-1-1 (E9-1-1) service for MLTS.  NENA is pleased to provide reference information related to MLTS technology and regulations throughout the United States. NENA encourages the adoption of MLTS E9-1-1 requirements in each State which will enable 9-1-1 and public safety agencies to receive the most accurate and precise location information in order to dispatch emergency response.

NENA MLTS model legislation

is available to provide guidance for developing State statutes and rules, as well as several technical reference documents to assist with implementation of E9-1-1 for MLTS.

06-750 NENA Model Legislation Enhanced 9-1-1 for Multi-line Telephone Systems, Version 2, February 19, 2009

The purpose of MLTS model legislation is to require Multi-line Telephone Systems to provide a sufficiently precise indication of the caller’s location, while avoiding the imposition of undue burdens on system manufacturers, providers and operators of MLTS. 

Documents are attached at the bottom of individual standards for download.

Technical - Network

  • 03-502 v1 - Trunking for Private Switch 9-1-1 Service

    This NENA TID defines three distinct alternative trunking configurations to accomplish the provisioning of Private Switch 9-1-1 Service (PS/911) in conjunction with the use of Private Branch Exchange (PBX) telephone systems. For PBX systems that use digital trunks, Primary Rate Interface Integrated Services Digital Network (PRI-ISDN) trunks, the provisioning of PS/911 may be accommodated without the requirement of dedicated trunks for transporting 9-1-1 calls. For PBX systems that use analog trunks (i.e. they are not compatible with PRI and/or PRI trunks are not available from local service providers), the provisioning of PS/911 may be accommodated by using dedicated circuits that operate with the Centralized Automated Message Accounting (CAMA) signaling protocol.

    Technical - Network

Technical - Data

  • 06-003 v2 - Private Switch (PS) E-9-1-1 Database

    Recent technical developments make it possible for Private Branch Exchange Telephone Systems (PBX) to provide Telephone Station level Automatic Number Identification (ANI). This NENA Technical Reference defines the requirements and methods to accomplish the provisioning of Private Switch 9-1-1 (PS/911) data in conjunction with the use of a Multi Line Telephone System (MLTS) or Private Branch Exchange (PBX) telephone system. For the purpose of this document and to be consistent with other NENA documents, a Private Branch Exchange telephone system or PBX will be referred to as a Multi-Line Telephone System or MLTS.

    Technical - Data
  • 06-501 v2 (Converted to TRD 06-750) - MLTS Model Legislation

    Converted to TRD 06-750 February 19, 2009.

    Technical - Data
  • 06-502 v1 - MLTS E9-1-1 Caller Location Discovery and Reporting

    Recent technology innovations have made it critically important for organizations to address the challenge of identifying the location of the users of communications systems during emergencies in the Multi Line Telephone System1 (MLTS) environment. This paper and the accompanying diagrams will discuss many of the issues related to the location of individuals during emergencies in the MLTS environment. It will further outline the current suggested methods of dealing with the challenge using commonly available technology as recommended in this document by NENA.

    Technical - Data
  • 06-750 v3 (Previously TID 06-501) - MLTS Model Legislation

    Recent technology innovations have made it important to update the MLTS Model Legislation recommended in 2000.  The following revised Policy document reflects changes in IP technology; Implementation & Testing; Training and the use of building code Fire Zones to facilitate the creation of the Emergency Response Location.

    Technical - Data