Real-Time Text (RTT) is a feature designed to improve communication in situations where talking or making a voice call is not possible—such as emergencies or for individuals who are deaf, hard of hearing, or rely on TTY for phone calls. In this post, I’ve put together a quick overview of RTT and how it works: Real-Time Text (RTT) in IMS.
RTT has been available in the U.S. since around 2021, and in Canada, the CRTC mandated its implementation in 2020. However, as of now (at the time of writing), Canadian providers are being urged to deploy it as soon as possible, especially for NG911 and emergency calls.
I recently implemented RTT support in our IMS core and tested it using two iPhones. Below, I’ll share some screenshots and a video to give a clearer picture of how RTT works and how it enhances communication.
Let’s see what we have in RTT Settings: (Settings > Accessibility > RTT/TTY)
First, you need to enable the RTT feature. There are three interesting settings you can adjust:
-
Send Immediately: When enabled, the phone sends each character as you type, rather than waiting for you to finish your message.
-
Answer RTT Calls as Muted: This setting caught me off guard at first—I couldn’t figure out why my calls had no audio. If enabled, RTT calls start with the microphone muted, so you’ll need to manually unmute if you want to speak.
-
Live Captions: A great accessibility feature for individuals with hearing disabilities. It allows users to read messages before answering and respond via text.
Let’s have a quick demo:
As you can see, one phone has the Send Immediately option enabled, while the other requires pressing Enter to send messages. You can also mute and unmute the audio during the call.
I hope this helps you understand how to enable and use the RTT feature, especially in emergency situations where you might not have been aware of it before.
Take care ;)