When a 911 Caller Can't Speak: RTT, Text-to-911, and Your Phone System

Most 911 planning assumes the caller can talk. Many can't. Some callers are deaf, hard of hearing, or have a speech disability. Others lose the ability to speak in the moment: a stroke, a seizure, an allergic reaction, or a threat in the room that makes speaking dangerous.

The 911 system has specific rules for reaching help by text. Enterprise phone systems often fall between those rules. This guide explains the three ways people reach 911 without speaking, what federal rules cover, and where your organization's gaps are likely to be.

Three ways to reach 911 without speaking

TTY

A TTY (teletypewriter) sends typed text over a phone line. Under the Americans with Disabilities Act, 911 centers must provide direct access to TTY callers, without routing them through a relay service, and that access must be as effective as it is for voice callers (U.S. Department of Justice).

Real-time text (RTT)

RTT is the IP-based successor to TTY. Text appears character by character as it's typed, so the conversation flows more like a phone call. In 2016, the FCC allowed wireless carriers and device makers to support RTT in place of TTY, and required that RTT calls to 911 meet the same location requirements as TTY calls. The FCC also required support for simultaneous voice and text on the same call, noting it can help when a person in distress needs to type an exact location or is no longer able to speak (FCC 16-169).

Text-to-911

Text-to-911 sends a standard text message to 911. It works only where the local 911 center has chosen to accept texts. Once a center requests it, wireless carriers and text messaging providers must deliver texts there within six months. Where text-to-911 isn't available, carriers must send an automatic bounce-back message telling the sender to reach 911 another way. The FCC's guidance is to call if you can, and use text when you can't (FCC).

Next Generation 911 is designed to carry text, photos, and video alongside voice, which will make these options more consistent over time. For background, see our guide, What Is NG911?

What the rules cover, and what they don't

The FCC's RTT rules apply to wireless, IP-based voice services. When it adopted them, the FCC concluded it was premature to apply RTT rules to wireline services (FCC 16-169). Text-to-911 obligations likewise fall on wireless carriers and text messaging providers.

That leaves most enterprise phone systems outside both sets of rules. A desk phone on Cisco Unified CM, a Microsoft Teams softphone, or a hosted BroadWorks line is built for voice. What those systems are required to do is set by Kari's Law and RAY BAUM's Act, and those requirements apply to every 911 call from the system, whether or not the caller says a word (FCC MLTS 911 requirements).

The silent call problem

A 911 call with no one speaking is not unusual. The Department of Justice notes that TTY calls often reach call takers as silent, open lines, and that silent lines have historically been mistaken for hang-ups. Its guidance tells 911 centers to query every silent call as a possible TTY call (U.S. Department of Justice).

On an enterprise phone system, a silent 911 call is where your compliance work pays off. If your system sends a dispatchable location, the dispatcher sees the building, floor, and room even though the caller can't say them. If your on-site notification works, your security team knows a 911 call just came from that room and can go there directly. A system that sends only a headquarters street address gives a silent caller almost nothing. Our guide to what counts as a dispatchable location covers what that address needs to include.

The mobile phone gap

People who rely on text often reach 911 from their own mobile phones, using RTT or text-to-911. Those calls and texts go through the wireless carrier, not your business phone system. That means two things.

No on-site notification. Kari's Law notification is triggered by your phone system. A mobile 911 call or text never touches it, so your security desk doesn't hear about it.
Less precise location inside large buildings. Wireless location may not identify the floor or room the way a properly configured desk phone does.

Planning for employees and visitors who can't speak means planning for mobile 911 activity on your property too, not only calls from your desk phones.

A checklist for IT and security leaders

Confirm dispatchable location for every device. A silent caller depends on it. Building, floor, and room or zone should travel with every 911 call.
Confirm on-site notification works and reaches someone. Notifications should go to a place that's staffed, with the caller's location included.
Test silent calls. Use your provider's 933 test number, where offered, and schedule live test calls through your local 911 center's non-emergency line. Confirm the location and notification come through without anyone speaking. Our 911 testing guide explains how.
Check any TTY lines you still run. If your phone system supports TTY devices, test them end to end.
Include the people affected. Ask deaf, hard of hearing, and speech-disabled employees what devices they use to reach 911, and build your emergency procedures around their answers.
Know your local 911 center's capabilities. Check the FCC's text-to-911 registry for each location you operate.
Plan for mobile 911 calls on site. Decide how security learns about 911 activity that never touches your phone system.

Close the gaps on both sides

Some of the most important 911 calls from your property will have no voice on the line. Your phone system's location data and notifications are what make those calls actionable.

9Line Dispatch delivers Kari's Law and RAY BAUM's Act compliance for Cisco Unified CM, Microsoft Teams Direct Routing, and Cisco BroadWorks, sending a dispatchable location with every 911 call and alerting your on-site team the moment someone dials. For 911 calls from mobile phones on your property, 9Line Pinpoint alerts your team when a cellular 911 call is placed inside your geofence. Talk to us about where your environment stands.