Set up and use RTT on iPad
With real-time text (RTT) and Wi-Fi calling on your iPhone, you can also make and receive RTT calls in the FaceTime app on your iPad.
Important: RTT isn’t supported by all carriers or in all countries or regions. RTT functionality depends on your carrier and network environment. When making an emergency call in the U.S., iPhone sends special characters or tones to alert the operator. The operator’s ability to receive or respond to these tones can vary depending on your location. Apple doesn’t guarantee that the operator will be able to receive or respond to an RTT call.
Set up RTT
Make sure you can make and receive Wi-Fi calls on iPad.
Go to Settings > Accessibility > RTT.
Turn on Software RTT, then do any of the following.
Tap Relay Number, then enter the phone number to use for relay calls using Software RTT.
Turn on Send Immediately to send each character as you type. Turn it off to complete messages before sending.
When RTT is turned on, appears in the status bar at the top of the screen.
Start an RTT call
Open the FaceTime app on iPad.
Tap New FaceTime, then type the name or number you want to call or tap to add a contact.
Tap , tap Call, then tap RTT Call or RTT Relay Call.
Type text during an RTT call
After accepting or a starting an RTT call in the FaceTime app on iPad, tap Use RTT, then tap .
Enter your message in the text field.
If you turned on Send Immediately in Settings, your recipient sees each character as you type. Otherwise, tap to send the message.
To also transmit audio, tap in the top-right corner.
Note: Standard voice call rates apply for RTT calls.