RTT (Real-Time Text) call is a modern IP-based communication service that transmits text as it’s typed instantly during a phone call, without the need to press a “send” button. It was primarily designed for hard-of-hearing or speech-impaired users, but now it has gradually become a practical solution for anyone who needs clear, reliable, and text-based communication during live calls.
RTT calls play an important role in various industries, such as customer service support, emergency communications, and regulated industries where clarity and accuracy matter. This service enhances accessibility, reduces misunderstandings, and creates text-based interaction without requiring additional apps.
Want to learn more details about RTT calls? This complete guide explores the definition, key features, and differences between RTT call vs TTY, SMS, live chat, and voice calls. We also dive into its business use cases, importance, and other valuable information.
What Is an RTT Call
RTT Call Meaning and Definition
An RTT call, short for Real-Time Text call, is an advanced communication method that allows text to be transmitted instantly as it is typed. Unlike SMS or traditional messaging apps, this method doesn’t require users to hit the “Send” button, making conversations feel immediate and interactive.
The main purpose of RTT calls is to enable real-time, text-based communication over standard phone networks, either alongside voice or as a text-only alternative. This focus on instant text transmission is precisely what sets RTT apart from traditional messaging systems, as Wikipedia’s definition clarifies:
“Real-time text (RTT) is text transmitted instantly as it is typed. Recipients can immediately read the message while it is being written, without waiting.”
This communication method combines a series of modern IP-based calling technologies, such as VoLTE (Voice over LTE) and Wi‑Fi Calling, which make text be transmitted over carrier networks with minimal delay, ensuring communication remains stable, responsive, and compatible with your smartphones.
Key Features of RTT Call
RTT calls offer a wide range of features that cater to both individual users and business needs. At their core, these features aim to improve clarity, accessibility, and real-time interaction.
1. Real-Time Text Transmission: Text displays on the recipient’s screen instantly as it’s typed, creating a natural, flowing conversation like in-person chat.
2. Voice and Text Hybrid Support: Support simultaneous voice and text transmission, allowing users to switch between mid-call based on preference or context.
3. Robust Accessibility Integration: Work with many supported devices, including phones, screen readers, hearing aids, and customizable text settings to meet diverse needs.
4. Cross-Platform Operations: Function across smartphones (iOS and Android), unified communication tools (e.g., Microsoft Teams), and emergency services, requiring only IP connectivity.
5. Enhanced Emergency Services: Integrate with emergency systems, like 911, allowing dispatchers to access critical information in real time—and ultimately reducing emergency response times.
How Does RTT Call Work
RTT calls work by relying on modern carrier networks to transmit text instantly during a call. To break this down, we’ll explain its technical flow, infrastructure, and role in emergency services.
Real-Time Text Transmission Explained
In an RTT call, real-time text transmission means that the recipient can see text as being typed. The process mirrors voice communication: just as spoken words are heard instantly, typed characters appear without delay. For instance, if a customer types “I need help with my order,” the agent can see the message in real time, even before the sentence is complete.
RTT Call Infrastructure (Carrier-Based)
RTT calls work through the IP-based network carriers (4G/5G, VoIP) and IP Multimedia Subsystem (IMS) to manage call sessions. Unlike older communication methods that relied on the Public Switched Telephone Network (PSTN), RTT calls rely on the same technologies as VoLTE (Voice over LTE) and Wi-Fi Calling.
RTT Call and Emergency Services (911)
RTT plays an important role in emergency communication. Many regions support RTT for 911 call as it allows individuals who cannot speak to communicate with emergency responders in real time. What’s more, emergency RTT calls can integrate with location services (including precise GPS data), improving response accuracy and accessibility in urgent situations.
RTT Call vs Other Communication Methods
Lots of users often mix up RTT calls with other communication methods like SMS, TTY, and Live Chat. To clear up the confusion, here we break down the key comparisons between them.
Comparison | RTT Call | TTY | SMS | Live Chat | Voice Calls |
Technology Foundation | IP networks (4G/5G, Wi-Fi, IMS) | Analog phone lines (POTS), Audio signals | Store-and-forward cellular messaging | Internet (HTTP/HTTPS), cloud platforms | Cellular/IP networks (VoLTE, VoIP) |
Key Features | Real-time text, voice-text sync, accessibility | Legacy text-only, turn-based transmission | Asynchronous text messages, send-and-receive model | Text chat with agents, often included in Chatbots and CRM tools | Voice-only (or video), real-time audio |
Hardware requirements | Smartphone only | Dedicated TTY device or adapter | All mobile phones; 2G+ networks | Smartphone, computer, or tablet with internet access | Phone or VoIP-enabled device |
Applications | Customer service support, emergency services | Hearing-impaired users (legacy use) | Personal messaging, notifications | Customer support, sales, and online assistance | Personal calls, business communication, emergencies |
Performance | ≤100ms latency, character-by-character | 1-3s latency, block transmission | 1-10s latency, full-message delivery | 50-200ms latency, message-based | Near instant, but affected by noise and audio quality |
Cost | Mobile phones, VoIP plans, and voice use minutes | 50− 200 hardware + line fees | Usually low or included in plan fees | Platform subscription and operational costs | Standard call charges or VoIP costs |
RTT Call vs TTY
Compared with RTT calls, TTY (Teletypewriter) is a legacy technology designed for text communication over analog phone lines. The most striking difference is that RTT works on standard smartphones without extra hardware, while TTY requires specialized devices.
RTT Call vs SMS
SMS (Short Message Service) is a store-and-forward messaging system where messages are sent only after pressing “send, designed for asynchronous communication. The main difference between them is real-time performance: RTT calls offer live, character-by-character communication, while SMS has a slight delay and splits long messages into segments.
RTT Call vs Live Chat
Live chat is an internet-based text communication tool for app and website interaction, relying on specific platforms or software. However, RTT calls work directly through carrier phone networks, delivering seamless, real-time text communication, without requiring extra software.
RTT Call vs Voice Calls
Voice calls are audio-based communication methods that can be affected by noise, accents, or hearing limitations, while RTT calls enhance voice communication by using real-time text, improving accuracy, and making communication more inclusive for all users.
Why RTT Calls are Valuable Today
RTT call communication delivers many benefits that make it a top choice for various use cases, from accessibility to customer support. Here’s why RRT is important today:
- Excellent Accessibility and Inclusivity: RTT enables those people who have difficulty in hearing or speaking to communicate effectively via text during phone calls. This removes the need for specific platforms and third-party apps.
- Critical Safety in Emergency Communication: In emergencies where voice communication is unsafe or impossible, RTT offers real-time text contact with emergency services like 911, improving response accuracy and safety.
- Enhanced Clarity and Versatility: RTT combines text and voice in one call, reducing misunderstandings due to noise, accents, or speech barriers. It’s ideal for personal or business uses that require high clarity and versatility.
- Broad Business Value: For modern customer service teams, RTT calls often provide richer interaction data, giving valuable insights into customer needs, pain points, and preferences to boost overall satisfaction.
RTT Call Use Cases for Businesses
RTT calls are widely used in various businesses that seek fast and efficient communication solutions. Here are 4 common use cases.
RTT Calls for Accessibility and Hearing Impairment
The primary use case of RTT calls is serving customers who have hearing and speaking impairments. It allows these customers to communicate with a business directly via real-time text transmission.
Example: A bank implements RTT support into their call centers. When a deaf customer called to report a stolen card, the agent’s questions and responses would be displayed on the screen instantly. This direct communication eases the customer’s anxiety and solves issues quickly.
RTT Calls in Customer Support
Real-Time Text calls are widely seen in customer support solutions as they reduce customer waiting time and improve resolution rates. Unlike chatbots or email, RTT connects customers directly to agents in real time.
Example: A telecom company integrates RTT for technical support. If a customer reaches out with a router problem, the agent can walk them through fixes verbally while using RTT text to type out complex IP addresses or configuration codes. This prevents data entry mistakes that often happen when customers are only listening to the information.
RTT Calls for Emergency Communication
For specific industries like public safety and healthcare, RTT calls provide an important communication channel during emergencies. They enable silent, real-time text communication, helping responders grasp critical details quickly and take action.
Example: During a workplace security incident, an employee hiding in a secure room can’t speak—afraid of giving away their location. He uses RTT to call the security line so dispatchers can read his real-time updates on location and status as typed. So, he gets immediate assistance right away, no words needed.
RTT Calls in Business Compliance
RTT calls help businesses meet strict accessibility and data privacy regulations, reducing legal risks and building trust. The EU’s GDPR and U.S. ADA require equitable communication access, and RTT ensures compliance by offering inclusive support for disabled users.
Example: A European airline adopted RTT to meet EN 301 549 compliance, avoiding a €20 million fine and opening its customer base to deaf travelers. RTT’s text logging feature also supports data retention law compliance, with conversations securely stored for audits—key for industries like finance and healthcare.
How to Turn On/Off RTT Call on Your Phone
The exact process may vary depending on your device and carrier. RTT is generally available on iPhone 6 and later, and most modern Android devices. To turn on or off the feature on your phone, you can follow the general tutorial below.
On iPhone (iOS)
1. On the iPhone device, tap on Settings and navigate to Accessibility.
2. Scroll down to the "Hearing" section and toggle on or off the switch next to RTT/TTY.
3. Once enabled, you will see a special icon in the status bar. If you want to make a call, select a contact, and choose the RTT/TTY Call option.
4. For emergency calls, ensure the RTT/TTY Emergency Calls option is enabled (it’s the default setting in iOS 14+).
On Android
1. Open your phone and tap on the “Gear-shaped” icon to open the Settings menu.
2. Look for Accessibility within the menu.
3. Tap on Real-time text (RTT) call to enable or disable it. Here, you can choose "Always Visible" (adds an RTT button to the call screen) or "Visible during calls."
4. After activating the feature, an RTT button will appear on the dialer interface when you make a call. This allows you to switch to text mode instantly.
FAQs
1. What is an RTT call on an Android phone?
An RTT call on an Android phone is a built-in feature that allows users to send text messages in real-time during a phone call. It’s a great choice for those who have hearing or speech difficulties or work in a noisy environment.
2. Is RTT the same as TTY?
No, RTT is the modern, digital replacement for TTY. TTY is an older analog technology that requires audio tones and often external hardware, while RTT is faster, supports simultaneous voice and text, and works directly on modern smartphones.
3. Is RTT calling secure?
Of course, yes! RTT calling is generally secure as it uses carrier networks instead of the open public internet. But the end-to-end encryption isn't guaranteed because privacy protection ultimately depends on your device settings and your mobile carrier’s security.
4. Why would someone call from RTT?
Someone may use an RTT call for different possible reasons. For example, they might be disable of hearing, or they need clear text-based communication in emergencies (e.g., 911) or noisy environments where voice calls fail.
