This feature is available on iPhone 6 and later with carrier plans from Verizon, AT&T, and T-Mobile.* Standard voice call rates apply for RTT calls.

Here's how to set up RTT:

Go to Settings > Accessibility > RTT/TTY. Turn on Software RTT/TTY. In the status bar at the top of your screen, you should see . Tap Relay Number and enter a phone number for TTY relay calls.

You can also change these settings:

To send characters as you type them, turn on Send Immediately. Or, to type full messages before you send, turn off Send Immediately.

To answer every call as TTY, turn on Answer All Calls as TTY. If you turn on Answer All Calls as TTY, you won't get voice calls anymore. Even if you turn on Answer All Calls as TTY, you can still upgrade any calls that you get by using the RTT button.

To answer and make TTY calls from an external TTY device instead of your iPhone, turn on Hardware TTY. Make sure that you also turn on Answer All Calls as TTY.

After you set up your iPhone, you can make and answer RTT calls, or upgrade a voice call to RTT.

You can make RTT calls on your iPad or iPod touch by setting up Wi-Fi calling on your iPhone.

Learn how to set up RTT on your Mac or Apple Watch.

* 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 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 or TTY call.