In the United States, you can make and receive RTT calls on Mac models introduced in 2012 or later (excluding Mac Pro) after updating to macOS Mojave 10.14.2. You also need an iPhone with a carrier plan from AT&T, T-Mobile, or Verizon. Standard voice call rates apply for RTT calls.
You can make and receive RTT calls on your iPhone as well.
How to set up RTT
- Set up Wi-Fi calling on your iPhone, making sure to add your Mac as one of the other devices to be used for Wi-Fi calling.
- From the Apple () menu, choose System Preferences, then click Accessibility.
- Select RTT in the sidebar. It appears only when Wi-Fi calling is set up correctly.
- Select Enable RTT.
- To send characters as you type them, select Send Immediately.
- Enter the U.S. RTT relay number: 711.
How to make an RTT call
- Your Mac uses FaceTime for RTT calls, but you can start the call from either Contacts or FaceTime.
- In Contacts, move your pointer over a contact's phone number, then click next to the number.
- In FaceTime, click the audio button next to the contact or after entering a phone number. Then choose RTT Call or RTT Relay Call from the pop-up menu.
- When the call is answered, click RTT to begin exchanging text messages in real time. While texting, you can also speak through your microphone, if available, or click Mute to mute your microphone.
- Type your message, then press Return or click to send it. If Send Immediately is turned on in RTT preferences, the other person sees your message as you type it.
- To hide your conversation, click RTT. While the conversation is hidden, you won't see messages the other person sends you. Click the button again to return to the conversation.
How to answer an RTT call
When you receive a call, click Accept to answer it. Then click RTT to begin exchanging text messages in real time.
How to end an RTT call
To end the call, click End.
- VoiceOver doesn't announce new RTT messages on Mac, so you should follow the conversation in the RTT window.
- Some carriers might disconnect the RTT call if no RTT messages have been exchanged for over 3 minutes.
RTT and TTY aren't supported by all carriers or in all regions. RTT and TTY functionality depends on your carrier and network environment. When making an emergency call in the United States, 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 or TTY call.