Re: TTY,

Hey there, and welcome to Apple Support Communities SherryMM,

We can certainly understand your concern and see you came to us from the article About the Accessibility Shortcut for iPhone, iPad, and iPod touch.

We recommend checking out these steps for more information on using TTY.

" What is RTT/TTY?

RTT (real-time text) allows you to send text messages with a recipient during a phone call. RTT can also be used with a TTY (teletypewriter) device.

This feature is available for plans from carriers in the United States and Canada only. Standard voice call rates apply for both Software and Hardware RTT/TTY calls. Depending on your carrier, you might see RTT, TTY, or RTT/TTY.

Set up RTT/TTY

1. Go to Settings > Accessibility > RTT/TTY. 
2. Turn on Software RTT/TTY or Hardware TTY.

3. Tap Relay Number and enter a phone number for RTT/TTY relay calls.

4. RTT/TTY sends characters immediately as you type them. If you don't want to send text as you type, turn off Send Immediately to send full messages after you're done typing.

5. To answer every call as RTT/TTY, turn on Answer All Calls as RTT/TTY.*

6. If you want to answer and make RTT/TTY calls from an external RTT/TTY device instead of your iPhone, turn on Hardware TTY. 

* If you turn on Answer All Calls as RTT/TTY, you won't get voice calls anymore.

Make or receive RTT/TTY phone calls

1. Open the Phone app.
2. Select your contact and tap their phone number.
3. Select RTT/TTY or RTT/TTY Relay.

4. Wait for the call to connect, then select RTT/TTY.

5. Enter your message.

If you turn on Send Immediately in Settings, your recipient sees your message as you type.

• If not, enter your message, then tap the Send button  to send.
• Want to find shortcut phrases? Wait a moment before you type your message and shortcuts appear, like SK for "Ready to hang up" and GA for "Go ahead." "

For additional information, check out this link: Answer or make RTT or TTY calls from your iPhone - Apple Support

Kindest regards!