Dina Bader: Apple Watch accessibility features include RTT calls

Yes, you can use RTT on your Apple Watch as long as you have a cellular model.

On Apple Watches with Cellular, you can use real-time text or RTT. The protocol transmits audio as you type text. Ideally suited for those with hearing or speech difficulties, RTT lets you communicate when you're away from your iPhone using built-in Software RTT that's configurable in the Apple Watch app.

Apple explains:

RTT is not supported by all carriers or in all regions. When making an emergency call in the U.S., Apple Watch 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.

How to turn on RTT
How to make an RTT call on Apple Watch
How to answer an RTT call on Apple Watch

Turn on RTT on Apple Watch

Tap on the Apple Watch app on your iPhone.
Under the My Watch tab, select Accessibility.
Tap RTT.
Toggle RTT to the On position.
Tap Relay Number
Enter the phone number to use for relay calls using RTT.
Tap RTT at the top left.
Turn on Send Immediately to send each character as you type.
Or turn off Send Immediately to complete messages before sending.

How to make an RTT call on Apple Watch

Your Apple Watch needs to be connected to a cellular network to place an RTT call. To make a call using RTT on Apple Watch:

Tap on the Phone app on your Watch.
Select Contacts.
Scroll, then tap on the contact you want to call
Tap on the phone icon.
Choose the number you'd like to call.
Tap RTT Call.
When the call connects, swipe up and tap the RTT icon.
Finally, leave your message. You can choose from the default replies, send an emoji, draw your text. If you've turned on Send Immediately in Settings, your recipient sees your message as you type. If not, enter your message and tap send.

How to answer an RTT call on Apple Watch

If RTT has been set up on your Apple Watch, you can answer an RTT call on your wearable device.

On your Apple Watch, tap Accept to answer the call.
Swipe up and then tap RTT.
Start a conversation with the caller.

If RTT hasn't been set up on your Apple Watch, you'll see a message "RTT allows text messages to be sent during a phone call between recipients. This service is typically used by those with hearing impairments. Press the RTT button to communicate using text with the caller." Tap Got It to accept the RTT call.

That's it! Now you know how to use RTT on your Apple Watch!