If you have hearing or speech difficulties, you can communicate by telephone using Teletype (TTY) or real-time text (RTT)—protocols that transmit text as you type and allow the recipient to read the message right away. RTT is a more advanced protocol that transmits audio as you type text. (Only certain carriers support TTY and RTT.)
iPhone provides built-in Software RTT and TTY from the Phone app—it requires no additional devices. If you turn on Software RTT/TTY, iPhone defaults to the RTT protocol whenever it’s supported by the carrier.
iPhone also supports Hardware TTY, so you can connect iPhone to an external TTY device with the iPhone TTY Adapter (sold separately in many regions).
Set up RTT or TTY. Go to Settings > General > Accessibility > RTT/TTY or Settings > General > Accessibility > TTY, where you can:
- Turn on Software RTT/TTY or Software TTY.
- Turn on Hardware TTY.
- Enter the phone number to use for relay calls with Software TTY.
- Choose to send each character as you type or enter the whole message before you send.
- Turn on Answer All Calls as TTY.
When RTT or TTY is turned on, appears in the status bar at the top of the screen.
Connect iPhone to an external TTY device. If you turned on Hardware TTY in Settings, connect iPhone to your TTY device using the iPhone TTY Adapter. If Software TTY is also turned on, incoming calls default to Hardware TTY. For information about using a particular TTY device, see the documentation that came with it.
Start an RTT or TTY call. In the Phone app, choose a contact, then tap the phone number. Choose RTT/TTY Call or RTT/TTY Relay Call, wait for the call to connect, then tap RTT/TTY. iPhone defaults to the RTT protocol whenever it’s supported by the carrier.
When making an emergency call in the U.S., iPhone sends out a series of TDD tones to alert the operator. The operator’s ability to receive or respond to TDD 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.
If you haven’t turned RTT on and you receive an incoming RTT call, tap the RTT button to answer the call with RTT.
Type text during an RTT or TTY call. 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 .
Review the transcript of a Software RTT or TTY call. In the Phone app, tap Recents, then tap next to the call you want to see. RTT and TTY calls have next to them.
Note: Continuity features aren’t available for RTT and TTY support. Standard voice call rates apply for both Software RTT/TTY and Hardware TTY calls.