While texting is great for asynchronous conversations, calls are still the way to go if you want real-time conversation.
That’s not an option for people who are hard of hearing or have speech difficulties. RTT or Real-time text solves this issue by allowing people to text in real-time. In this guide, Android Police explain the RTT feature, how to activate it on Android smartphones, and how to use it in different situations.
One benefit of RTT over text messaging is that it allows you to connect to businesses, government agencies, and emergency services. To connect to emergency services using RTT, all you do is dial 911 (in the USA) in RTT mode.
This feature makes emergency services accessible to people with hearing or speech disabilities and allows everyone to connect to emergency services without speaking. If you are in a situation where speaking out loud can be detrimental to your safety, use the RTT feature to connect to 911.
To connect to government agencies or businesses, you can use the Relay service. People who are hard of hearing or have speech impediments can connect to the relay service by dialling 711 (probably also USA). An operator picks up their call and connects them to the desired service.