7.4 Non-Voice Communications & Information Networks
Key Takeaways
- Non-voice channels in the ENP Body of Knowledge include telematics, SMS text-to-911, real-time text (RTT), email, multimedia, social media, and device applications, each with different delivery paths and policy needs.
- SMS text-to-911 reaches PSAPs through text control centers under the J-STD-110 architecture, and FCC rules (47 CFR § 9.10(q)) require bounce-back messages where text is unavailable; the public message remains 'Call if you can, text if you can't.'
- Real-time text transmits each character as it is typed (IETF RFC 4103), supporting conversational flow and serving as the IP successor to TTY, while SMS sends whole messages.
- Email and social media are not emergency reporting channels; PSAPs should say so clearly and follow social media guidance such as NENA's social networking information document and APCO ANS 1.112.
- The Internet, intranets, LANs, WANs, and WLANs serve different roles in a PSAP, and each needs segmentation, redundancy, and security controls appropriate to mission-critical and CJIS systems.
Last updated: September 2026
7.4 Non-Voice Communications & Information Networks
Quick Answer: PSAPs increasingly receive information without a voice call. Telematics systems report vehicle crashes, SMS text-to-911 reaches PSAPs through text control centers, and real-time text (RTT) streams characters as they are typed. Multimedia (photos and video) arrives with NG9-1-1, while email, social media, and device applications create public expectations that PSAPs must manage with clear policies. Behind all of these sit information networks: the public Internet, private intranets, local area networks (LANs), wide area networks (WANs), and wireless LANs (WLANs), each with its own reliability and security requirements.
1. Non-Voice Communications
| Channel | How It Reaches the PSAP | Rules and Standards | Operational Considerations |
|---|---|---|---|
| Telematics | Vehicle systems contact a telematics service provider, which relays voice and crash data; NG9-1-1 supports vehicle-initiated calls with data (IETF RFC 8148) | Provider agreements; NG9-1-1 Additional Data | Crash data (such as delta-V) supports triage; confirm location and occupants (7.2) |
| SMS text-to-911 | Wireless carrier to a text control center (TCC), then to the PSAP by web browser, TTY emulation, or native i3 interface | J-STD-110; FCC rules at 47 CFR § 9.10(q), including bounce-back messages | Messages can be delayed and lack conversational flow; location is often coarse; train for short, direct questions |
| Real-time text (RTT) | Characters stream from the device as typed over IP networks; legacy PSAPs may receive it converted to TTY | IETF RFC 4103; FCC rules allowing wireless IP networks to support RTT in place of TTY | Supports natural conversation and pre-arrival instructions; the IP successor to TTY (6.2) |
| Agency email accounts | Public records laws | Not an emergency reporting channel; target of phishing; route emergencies to 9-1-1 | |
| Multimedia | NG9-1-1 can deliver photos and video with a call; some apps and clearinghouses supply media | Agency policy; records retention; evidence handling | Decide when to accept media, how to store it, and how to protect telecommunicators from traumatic images |
| Social media | Public posts, comments, and messages on agency accounts | NENA's social networking information document (NENA-INF-001); APCO ANS 1.112 on social media in public safety communications | Accounts should state they are not monitored for emergencies; use for public information and rumor control (18.3) |
| Device applications (apps) | Apps may place calls, send data through clearinghouses, or share location and medical profiles | Vendor terms; privacy law; NG9-1-1 Additional Data | Treat app data as supplemental; verify location; beware apps that claim to reach 9-1-1 but do not |
Text-to-911 Essentials
- Deployment is PSAP by PSAP: Carriers deliver texts after a valid PSAP request, and a sender in an area without service receives a bounce-back message telling them to call.
- Best practice message: "Call if you can, text if you can't."
- Handling tips: Ask for location first, use short plain-language questions, avoid abbreviations the caller may not know, and document the full transcript.
- Canada: Text with 9-1-1 (T9-1-1) serves Deaf, hard-of-hearing, and speech-impaired people who pre-register their phones; the caller dials 9-1-1 by voice first, and the call-taker starts the text session (10.4).
Real-Time Text vs. SMS
| Feature | Real-Time Text (RTT) | SMS |
|---|---|---|
| Transmission | Character by character as typed | Whole message when the sender presses send |
| Conversation flow | Natural, like a TTY or voice call | Stop-and-start, with possible delays |
| Simultaneous voice | Can be used alongside voice on supporting devices | Separate from voice |
| Relationship to TTY | The IP-based successor to TTY | Not related to TTY |
2. Non-Voice Policy Checklist
- Intake priorities: Define how text, RTT, and multimedia sessions are answered and prioritized alongside voice.
- Location verification: Require location confirmation on every non-voice session.
- Media handling: Set rules for accepting, viewing, storing, and releasing images and video.
- Wellness: Limit unnecessary exposure to graphic media and include it in critical incident stress programs (15.3).
- Records: Apply retention schedules and public records rules to transcripts and media (18.1).
- Public education: Explain what channels work for emergencies (18.3).
3. Information Networks
| Network | Definition | PSAP Uses | Key Considerations |
|---|---|---|---|
| Internet | The public, global network of networks | Cloud services, vendor support, public websites, email | Best effort and exposed to threats; keep critical systems segmented and protected |
| Intranet | A private network that uses internet technologies to share information and services within an organization | SOP libraries, internal portals, training materials, scheduling | Access control and authentication; not reachable by the public |
| Local Area Network (LAN) | A network within a building or campus | CAD servers, call handling positions, recorders, radio consoles | Segment with VLANs and firewalls; redundant switches and power |
| Wide Area Network (WAN) | A network linking sites across a region | Backup PSAP links, hosted CHE, remote radio sites; an ESInet is a specialized public safety WAN | Carrier diversity, managed services (MPLS, SD-WAN), QoS |
| Wireless LAN (WLAN) | A LAN using Wi-Fi (IEEE 802.11) radio links | Administrative laptops, guest access, some mobile devices in the building | Strong encryption and authentication (WPA3 or WPA2-Enterprise with 802.1X); keep guest traffic separate; avoid relying on Wi-Fi for critical console links |
Designing PSAP Networks
- Segmentation: Separate call handling, CAD, radio, administrative, and guest networks, and control traffic between them.
- Redundancy: Duplicate core switches, firewalls, power, and WAN links, with diverse carriers where possible (12.3).
- Security: Apply NG-SEC and CJIS requirements, multi-factor authentication, patching, and monitoring (9.1 and 9.2).
- Performance: Use QoS for voice and video traffic, and monitor latency and packet loss (3.1).
4. Operational Traps & ENP Exam Watch
- RTT Streams, SMS Does Not: RTT sends each character as typed; SMS sends whole messages.
- Bounce-Back Is a Carrier Duty: Where a PSAP cannot receive texts, the text provider must send the bounce-back message.
- Email and Social Media Are Not 9-1-1: Agencies should state clearly that these channels are not monitored for emergencies.
- Intranet vs. Internet: An intranet is private to the organization even though it uses internet technology.
- An ESInet Is a WAN: It is a managed, private public safety WAN, not the open Internet.
- Secure the WLAN: Wi-Fi needs enterprise-grade encryption and authentication, especially near CJIS data.
Test Your Knowledge
What is a key difference between real-time text (RTT) and SMS text-to-911?
A
B
C
D
Test Your Knowledge
Which description best defines an intranet?
A
B
C
D
Test Your Knowledge
A PSAP public information officer is asked whether residents can report emergencies through the agency's social media accounts. What is the best practice?
A
B
C
D