Skip to content

Interim Text-to-911

Interim SMS Text-to-911 Information and Planning Guide

Version 2    May 2014

Produced by the Ad Hoc National SMS Text-to-9-1-1 Service Coordination Group (SCG)
(see Appendix A for SCG purpose and list of stakeholder organizations)


The purpose of this Guide is to provide a detailed overview of the Interim SMS text-to-9-1-1 solution. The document describes the service, areas of consideration for Public Safety, and related planning and implementation recommendations. Portions of this document have been adopted from multiple sources, including early adopters.

Target audience:  Public Safety management (9-1-1 Authorities and PSAP managers)



The interim text-to-9-1-1 solution will utilize the most commonly available texting technology, carrier native Short Message Service (SMS) texting. Carrier native SMS is that feature provided by the carrier, and not a third party texting or messaging application (app) that may be installed on the mobile device. The SMS interim text-to-9-1-1 service provides support for wireless subscribers to send 9-1-1 SMS text messages to PSAPs and for subscribers to receive text replies from PSAPs. Wireless customers with SMS service are able to send emergency SMS messages to a PSAP by using the single code “911” as the destination address of the SMS message.

According to the National Organization on Disability (2007), there are an estimated 54 million individuals with a disability in the United States, which has a total population of more than 300 million.  Over 37 million individuals are deaf, hard of hearing, or have a speech disability.

In December 2012, an agreement was reached among the largest four wireless carriers (AT&T, Sprint, T-Mobile, and Verizon), NENA, and APCO to provide a nationwide, interim SMS text-to-9-1-1 solution by May 15, 2014. Since the time of the agreement, work to bring SMS text-to-9-1-1 service into reality has progressed in various stakeholder groups.fn1

SMS Text-to-9-1-1 – what it is and isn’t

The interim solution will only process text-to-9-1-1 messages via carrier native SMS.  This means that photos, videos, or multiple recipients for a text message are not supported, as those cause the message to be sent as a Multimedia Messaging Service (MMS) message.fn2

SMS text-to-9-1-1 service is national in scope and is independent of any vendor applications implemented in individual PSAPs.

While the interim SMS text-to-9-1-1 solution may provide the most overall benefit to the deaf, hard of hearing, and speech disability communities, it can be used by the general public, especially in situations which include incidents of domestic violence in which case a voice 9-1-1 call could endanger the victim further, or in situations in which passengers in vehicles are determined to text to emergency services to report a driver doing drugs or drinking. Public advocacy will include the concept of “call when you can, text if you can’t.” Indiscriminant texting to 9-1-1 will be highly discouraged.

Why Public Safety should quickly embrace Interim SMS Text-to-9-1-1

  • Instead of having to rely on third party access to 9-1-1 call centers that could delay the emergency response process, the interim solution allows direct access to 9-1-1 telecommunicators for individuals who are deaf, hard of hearing, or have speech disabilities, and possibly save lives in other dangerous situations where voice calls are not possible.
  • Support federal objectives and expectations.
  • The Department of Justice (DOJ) filed comments in the FCC text-to-9-1-1 rulemaking stating that “in fulfillment of PSAPs’ existing obligation to provide effective communication under Title II of the [American with Disabilities Act], PSAPs must accept a call from a person with a hearing or speech disability that originates as an SMS call, but reaches the PSAP as a TTY call.” DOJ has an open rulemaking on NG9-1-1 obligations for PSAPs, which may result in additional guidance in the near future. For more information, go to:
  • The Federal Communications Commission continues to consider obligations for wireless carriers to provide text-to-9-1-1, as an interim text solution for when a voice call to a PSAP is not possible (or appropriate). The FCC also is considering improved indoor location accuracy for wireless callers.  For more information on the FCC’s text-to-9-1-1 efforts, the Commission has a web page that is kept updated to cover text-to-9-1-1:

Why is SMS text being used for interim text-to-9-1-1

  • To assist Public Safety in responding to the carrier/NENA/APCO commitment of December 2012
  • 2012 activities leading to SMS solutionEstablished by the FCC pursuant to The Twenty-First Century Communication and Video Accessibility Act of 2010 (“CVAA”), the Emergency Access Advisory Committee (EAAC) recommended that an achievable interim method for text-based messaging to 9-1-1 would be necessary until Next Generation 9-1-1 (NG9-1-1) is fully developed, deployed and adopted by industry, public safety and consumers.  In furtherance of this recommendation, the EAAC requested that all stakeholders, including industry, consumers, public safety, the FCC, and the Department of Justice, work together to find an interim solution that could be rapidly deployed to provide nationwide access to 9-1-1 services through an industry standards-based mobile text communications solution(s) to provide critical coverage for people who are deaf, hard of hearing and or have speech disability during the transition to NG9-1-1. In January 2012, the EAAC designated a subcommittee to make recommendations to encourage the availability of pre-NG9-1-1 interim text-to-9-1-1. In March 2012, the EAAC adopted a resolution to support “as an interim solution for text-to-9-1-1, at a minimum, SMS, and other technologies as appropriate, with a three digit short code 9-1-1.” More information about the EAAC and its reports and recommendations, can be found at:
  • SMS text standards and service capability are already in place in national carrier networksSMS has been available for some time in carrier networks for general texting support. As such, the necessary standards and capabilities already exist and are in use, and SMS was viewed as the most easily and quickly adaptable method to support a national text-to-9-1-1 service.
  • Intent to provide text capability to PSAPs without equipment/software costsThe original plan for interim text involved two fundamental ideas: SMS system architectures would not be modified and interface options to the PSAPs would include at least one service choice that would not require additional PSAP equipment or software costs. It was recognized that PSAP training would be required on the use of SMS text-to-9-1-1 service.

Why SMS to 9-1-1 text service is interim (compared to MMES and NG9-1-1 in the future)

Other national text services are not viable in the near term. A number of other capabilities in both the carrier and Public Safety networks are required in order to support alternate forms of text messaging beyond SMS in conjunction with NG9-1-1 designed text delivery.

This includes Multimedia Emergency Services (MMES), which must be implemented in carrier systems, and which requires IP interfaces between carriers and NG9-1-1 systems. When these standards are completed, testing and implementation must follow. Of course, NG9-1-1 systems must be in place to take advantage of the multimedia content that this type of text messaging provides.

MMES standards tailored for North America are currently being developed in ATIS, a US-based standards development organization. These standards will be based on existing international (3GPP) standards for MMES; MMES will allow for simultaneous use of pictures, videos, text, and voice between an emergency caller and a PSAP. However, ATIS MMES standards are not yet completed and therefore an MMES solution is not likely to be available from all carriers for several years. In the interim, text to 9-1-1 using existing SMS technology will provide an acceptable short-term solution (beyond the existing voice calling to 9-1-1) for emergency callers to be able to communicate with PSAPs.

PSAP Training and Public Education

The agreement on interim SMS text involved NENA and APCO taking responsibility for developing PSAP training and support aspects.  That development work has been under way in preparation for trial and availability by May 2014.   PSAP training and standard operating procedures for handling text are basically consistent with call processing for TTY calls.

PSAP training and Standard Operating Procedures (SOP) information and resources or links can be found at:

Public education is being coordinated by the FCC, and resources for that purpose are being developed by several organizations, such as NENA, APCO, the National 9-1-1 Office, and the FCC.  Additionally, PSAPs are encouraged to consult with their local seniors, deaf, hard of hearing, and speech disability communities to identify and address local concerns, and to ensure effective consumer outreach regarding Interim SMS text-to-911.  Some national advocacy organizations have local membership chapters and you can locate contacts in your area by looking at their web sites.  A few such web sites are:

Public education resources and links can be found at the following web sites :

How Interim SMS text-to-9-1-1 works

The interim solution has three interface delivery options, two of which allow Public Safety entities that have not begun deploying NG9-1-1 services to still have the capability to receive text messages. The location-based routing of SMS text-to-9-1-1 messages parallels that of wireless Phase I,fn5 that is, based on cell site and sector. As we know, cell sector coverage does not generally follow community, PSAP jurisdictional, or county boundaries, so SMS text-to-9-1-1 cannot be limited to these geographic oriented boundaries. Yet, the consumers who wish to use SMS text to 9-1-1 must have some clear, understandable idea of where they can and cannot utilize the service. It is believed that county-oriented service is preferable, whether temporarily to a single PSAP in multiple PSAP counties, or to all PSAPs in a county at the onset. PSAP by PSAP implementation can be confusing to the consumer, due to lack of service area clarity.

A `bounce back’ message has already been implemented by the `big four’ carriers, as of June 30, 2013, for anyone who attempts to use SMS text-to-9-1-1 prior to local service availability or when the service may be otherwise unavailable. The remaining carriers were required by the FCC to implement bounce back messages by September 30, 2013.

The Interim SMS text-to-9-1-1 solution will not be supported when a subscriber is roaming, due to SMS service limitations. Instead, the subscriber will receive a bounce back message explaining that SMS text-to-9-1-1 service is not available and to contact 9-1-1 by another method, such as a voice call or relay service. In the context of SMS text-to-9-1-1, roaming means the subscriber is receiving wireless service from any carrier other than his/her home carrier, regardless of the subscriber’s current location.

Text Control Center - Nationally, the wireless carriers and their vendors are deploying Text Control Center (TCC) functions to interface between a carrier-originated wireless 9-1-1 text user and the PSAP environment. The TCC uses some of the functions of core NG9-1-1 system design, with additional specialized functionality to meet the needs of SMS text-to-9-1-1. When TCCs from different vendors are able to interoperate with each other, PSAPs can connect to multiple carriers through a single TCC.

SMS Interim Text-for-9-1-1 Diagrams

[ cLBS = commercial location-based service ]

The above diagram shows the TCC with each of the three interface delivery options outlined in J-STD-110. Each of these interface options involve preparatory steps for the PSAP, (see section on Planning for SMS text-to-9-1-1 below), as well as establishing routing plans and overflow/alternate routing agreements and rules for text messages between wireless carriers/TCC operators and Public Safety entities.

As standards development work continues, there is a need to define new Class of Service values (e.g., displayed as “TEXT”, “TXT1” , “TXT2”, or similar). Further development discussion is needed on whether there will be different class(es) of service to identify a SMS text-to-911 message.

ESInet/IP i3 Network Service Interfacefn6 – this option would require the PSAP to have IP capable equipment and IP connectivity to a designated TCC, either a carrier’s TCC or a special purpose TCC that interworks with one or more carrier TCCs. The text message will be delivered into the 9-1-1 PSAP CPE interfacefn7. This solution is compatible with a standard NG9-1-1 (i3 compliant) solution. The ALI display will contain information similar to what is presented for a wireless caller today, including the x/y coordinates of the cell site or the cell sector centroid.

Web Service – this option would require a PSAP to have IP-based access, either through a private IP network or over the public Internet. A separate web portal would be opened at the beginning of the shift and would need to be monitored for incoming text messages. This solution requires a separate browser window and in some cases may require a separate monitor for the web portal; however, some equipment manufacturers have incorporated the portal into the 9-1-1 user display. The ALI will display the telephone number associated with the device used for texting and x/y coordinates of the cell site or the cell sector centroid associated with the texting device.

TTY/TDD Text – this option would allow the PSAP to receive incoming text messages via E9-1-1 and their current TTY/TDD system. The text would display on the existing 9-1-1 equipment similar to how a typical TTY call is received. The ALI display will show the caller’s telephone number in the place where the wireless caller’s Call Back Number is displayed on voice calls, and the x/y coordinates of the cell site or the cell sector centroid associated with the texting device. The text messages would be delivered via the existing 9-1-1 trunks, which would mean that once a text came in via this method, the 9-1-1 trunk over which it arrived would be tied up and unable to accept another voice call or text session.

TCC Interconnection

Interconnections between different TCCs – PSAPs will be connected to at least one TCC in order to support the interim SMS text-to-9-1-1 service. Since some carrier TCCs will be ready to be interconnected before others, there is an option for a PSAP to stay interconnected to just a single TCC. This can be in the form of a specific carrier TCC as shown in the following diagram, or may be a separate aggregation service offered by a TCC service provider that provides additional features and capabilities.

Early Adopter Deployment Experiences

Call volume impacts, based on current, limited trials and deployments of SMS text-to-9-1-1, have shown that concerns about PSAPs being overwhelmed by texts to 9-1-1 may be unfounded. A proactive public education campaign will make a difference in how the public perceives and utilizes text-to-9-1-1.. As of April 2014, there is no indication that text-to-9-1-1 causes significant numbers of text messaging for emergencies. In fact, the opposite is true. Reports from the state of Vermont, and North Carolina communities around Raleigh-Durham, demonstrate that text-to-9-1-1 is not a burden to the PSAP operations. Reports about these trials and deployments of text-to-9-1-1 are available at:

The FCC maintains a list of specific areas where text-to-9-1-1 may be currently available, and this list is located at this webpage:
An early adopter summary of several states and areas is provided in Appendix G

Planning for SMS text-to-9-1-1 service by 9-1-1 Authorities

Public safety should plan for SMS text-to-9-1-1 on a county or multi-county basis. As noted above, cell sector coverage does not follow community, PSAP jurisdictional, or county boundaries, so SMS text-to-9-1-1 cannot be limited to these geographic oriented boundaries. Yet, the consumers who wish to use SMS text to 9-1-1 must have some clear, understandable idea of where they can and cannot utilize the service. For various reasons, it is believed that a county-oriented service approach is preferable, whether temporarily to a single PSAP in multiple PSAP counties, or to all PSAPs in a county at the onset. PSAP by PSAP implementation can be confusing to the consumer, due to lack of service area clarity.

If a PSAP CPE upgrade includes support for SMS text, the CPE upgrade should be scheduled in advance of SMS text implementation. In concert with the planned SMS text interface method, the 9-1-1 Authority or PSAP manager will need to discuss, arrange, and schedule any equipment upgrades with their 9-1-1 System Service Provider or their equipment vendor. (See interface descriptions above under `How Interim SMS text-to-9-1-1 works’ and in applicable carrier or TCC provider documentation.)

In areas where there is no PSAP text coverage, the 9-1-1 texter receives a default (bounce-back) message similar to, “Please make a voice or relay call to 9-1-1. There is no text service to 9-1-1 available at this time.”

A PSAP may be authorized to take text messaging for other affiliated PSAPs on a temporary basis, through an agreement between PSAPs within or between Public Safety organizations. (See first page of Questionnaire in Appendix C.)

SMS text transfer capabilities between PSAPs are dependent on specific vendor implementations.

Planning Background and Considerations

The wireless carrier and their Text Control Center provider route text messages to the appropriate PSAP over the selected interface based on the cell sector, and provide the PSAP with a latitude/longitude location of the calculated centroid for the center of the cell sector RF coverage (e.g. coarse location) using commercial location positioning service.

More precise texter location may be available, but is carrier/vendor implementation specific.

Interim SMS text-to-9-1-1 service is only available to valid wireless subscribers with a text-capable phone and service plan that includes text messaging.

The interim SMS text-to-9-1-1 solution is not limited to people who are deaf, hard of hearing, or have speech disabilities. The public is advised to utilize SMS text only when a voice call is not possible or advisable.

It is highly recommended that planning for SMS Text-to-9-1-1 include consultation and input from hearing and speech organizations in your county or area. Getting their input and help in public education efforts and PSAP operations procedures will assist in a smooth implementation of the service
To better set expectations, the PSAP must understand the role and responsibilities associated with each of the options for Interim text-to-9-1-1 service interconnectivity.

SMS to PSAP via IP connectivity (ESInet/IP Network Service Interface)

  • PSAPs install dedicated, redundant IP circuits to the Text Control Center at their own expense or has an ESInet in place
  • PSAP customer premise equipment (CPE) must be capable of receiving IP messages on standard (NENA i3 and ATIS J-STD-110 defined) IP interfaces (SIP/MSRP)
  • Call taker workstations must have integrated text handling software
  • PSAP is responsible for CPE equipment (upgrades/maintenance/technical support), firewall configurations and text call taker training
  • PSAP must provide point of contact for CPE and IP/ESInet customer support
  • SMS text is delivered to the PSAP and MIS/RMS and logging/recording capability is included

SMS using Web Service method

  • PSAP must have public Internet or private IP network connectivity into workstations readily available
  • PSAP workstations must have web browser capability (IE8 or higher, Chrome or Firefox)
  • PSAP is responsible for CPE equipment (upgrades/maintenance/technical support) and firewall configuration (if applicable)
  • Text is not delivered to the PSAP literally, must be managed at the web server via the Internet or a private IP network
  • MIS/RMS and PSAP logging/recording functions are not active during the text session, and such data are obtained from the web server separately
  • PSAP must provide point of contact for CPE customer support
  • The PSAP needs to be logged in at the beginning of each shift in order to be aware of text message alerts.

SMS to TTY Conversion

  • SMS converted to TTY (Baudot code) before sent to Public Safety 9-1-1 network
  • TTY messages sent to E9-1-1 Selective Router for delivery to the PSAP TTY call station
  • PSAP should bid ALI with ESRK/pANI for coarse location (e.g. cell site and sector) related to the subscriber’s call
  • PSAP is responsible for CPE equipment (upgrades/maintenance/technical support) and call taker training, if required
  • PSAP must provide point of contact for CPE customer support
  • SMS text as TTY messages is delivered literally to the PSAP, and MIS and recording capability are included if TTY functions are integrated with CPE
  • ‘Garbling’ with SMS sent as TTY is expected to be no different than TTY at a PSAP today
  • Proper setup, prior to deployment, is required in the interconnecting networks and elements and at the PSAP to minimize Bit Error Rate
  • Observed PSAP considerations to date include:  Local TTY terminal modem settings, volume settings, PBX configurations, CPE configurations, etc.

Request for Service process

After the planning process for each PSAP and its selected interface are underway, the 9-1-1 Authority should prepare the service questionnaire(s) and the Request for Service letter (Appendix C and D), and send to each involved carrier. Consider doing this via registered mail, in order to establish receipt date as a base for the implementation process.

See Appendix E for description of information to be supplied by Public Safety

Implementation process

Public Safety management should review the carrier implementation plan (Appendix F) and consider what Public Safety steps need to be taken in preparation for implementation. The carrier and their TCC provider will coordinate start date and work for the implementation steps.

PSAP by PSAP testing

The carriers have defined test plans (see Appendix F) for each interface type. Public Safety management should review these plans in advance and determine whether any other testing is needed, negotiating with carrier and/or TCC representatives as needed. Specific testing procedures and schedules for testing should be determined in advance.

Ongoing Operations

At minimum, management of alternate routing and out of service routing plans will be required. For this and other purposes, maintaining contacts at the carriers and TCC providers is necessary.


Appendix A

Appendix B

Appendix C

Appendix D

Appendix E

Appendix F

Appendix G


fn1 These include the ad hoc national SMS Text to 9-1-1 Service Coordination Group (which produced this document), AT&T, ATIS, APCO, CTIA, DOJ, DOT – 9-1-1 Office, FCC, Intrado, LRKimball, NENA, Sprint, TIA, T-Mobile, TeleCommunication Systems (TCS), Verizon Wireless

fn2 MMS is a way to send messages that include multimedia content to and from mobile phones. It extends the core SMS capability that allows exchange of text messages. The most popular use of MMS is to send photographs from carrier-equipped handsets. However, MMS messages are delivered in a completely different way from SMS.

fn3 For the full Department of Justice letter, see:

fn4 FCC rulemaking docket # 11-153.

fn5 Wireless E9-1-1 Phase I is the delivery of a wireless 9-1-1 call with callback number and location information of the cell-tower and sector from which the call originated. Call routing is usually determined by cell-sector.

fn6 A potential vendor implementation option exists for PSAPs that uses a direct IP network but that is not yet NG9-1-1 capable – instead leverages i3 SIP/MSRP PSAP CPE equipment and applications to support the receipt of text messages. Such an approach is considered negotiable on a case-by-case basis by some carriers, and would require the same standards based IP interface, and must be designed by the vendor to interact with the TCC functional features.

fn7 As of January 2014, the NG9-1-1 interface is not yet fully available, which may delay its utilization by May 2014. This interface is to be used as both a TCC/ PSAP interface and an interface between TCCs.