Teletype (TTY) in Xiaomi Redmi 9T: purpose, configuration and features of use

If you've ever looked into the call settings on your Xiaomi Redmi 9T, you've seen the mysterious Teletype (or TTY) option. For most users, the term sounds like something from the last century -- and it's partly true. But the teletype feature is still present in modern smartphones, including the Redmi budget models, and has an important social role.

In this article, we will discuss in detail what a teletype in a phone is, why you need it in the Xiaomi Redmi 9T, how to turn it on or off, and in what situations this feature can be useful. You will also learn about the nuances of TTY on Android, possible problems and alternative ways of communication for people with hearing impairments. If you have never used a teletype, but want to understand its purpose, this material is for you.

What is a Teletype (TTY) and why you need it in a smartphone

Teletype (TTY, Teletypewriter is a text-messaging technology that was originally developed for people with hearing or speech impairments. XIX In the middle of the century, but in telephony they were actively used. XX The point is simple: instead of voice conversation, subscribers exchange real-time text messages through special terminals.

In modern smartphones, including the Xiaomi Redmi 9T, TTY emulates the operation of these devices software.

• 📞 Conduct text dialogues via a regular telephone network (without the Internet).
• 🔄 Connect externally TTY-devices via cable or Bluetooth.
• 📱 Use the phone as a terminal to communicate with subscribers who also have it on TTY.

It's important to understand that teletype is not SMS or messengers, it works directly through the voice channel, converting text into audio signals that are decoded at the other end, which makes TTY indispensable in situations where the Internet is not available and SMS is blocked or paid.

How does the teletype on Xiaomi Redmi 9T: technical details

At Redmi. 9T Teletype is implemented at the level of the Android operating system and is supported by most mobile operators. TTY The phone is in a special mode where:

• 🎤 Microphone and speaker are turned off for voice communication.
• ⌨️ Instead, text input is enabled via the keyboard.
• 📡 Signals are transmitted in audio format over a standard voice channel.

Technically, Xiaomi Redmi 9T supports several TTY modes:

Data transfer speeds in TTY-It's low, about 45.45 bpd, which is comparable to the ancient modems, but that's enough for text messages. TTY, Otherwise, the connection will not be established.

⚠️ Attention: In mode TTY You can't send voice and text at the same time. TTY, Standard calls will not be available until the function is disabled.

Where is the setting of the teletype in Redmi 9T: step-by-step instructions

To enable or disable teletype on Xiaomi Redmi 9T, follow this instruction:

1. Open the phone application (pipe icon).
2. Click on the three dots in the top right corner and select Settings.
3. Go to Calls → Additional (or Other settings, depending on the version of MIUI).
4. Find the Teletype (TTY) item and tap it.
5. Select the desired mode: Full, HCO, VCO or Rec.
6. Confirm the changes and return to the main menu.

Check your operator's TTY support | Make sure the interlocutor also has TTY| Battery charge of at least 30% | Turn off power saving modes-->

If you don't have a Teletype on your menu, it might be hidden.

• 🔍 Check the version. MIUI: in old firmware (below) MIUI 12) the option could be called differently.
• 📱 Update your phone to the latest version of the software through Settings → The phone. → Updating the system.
• 🔧 Use the search in the settings: enter «TTY» search-line.

Once TTY is activated, a special keyboard will appear on the call screen to type in text, and messages will be displayed in real time, like in a chat.

When can a teletype be useful in 2026?

Despite the development of instant messengers and video calls, teletype remains relevant in several scenarios:

1. For people with hearing or speech impairments, TTY allows you to communicate on the phone without having to hear or talk, which is especially important in emergency situations (such as calling an ambulance).
2. In areas without internet, if you don't have access to WhatsApp, Telegram or SMS, TTY will remain operational via the standard telephone network.
3. Some support services (e.g. banks or operators) still support TTY for disabled clients.
4. In areas with poor coverage, voice communication may be interrupted and TTY text messages may be more stable.

In Russia and CIS countries, TTY support among telecom operators is limited, but companies such as Beeline and MegaFon officially declare their networks compatible with this technology.

💡

If you often communicate with a person who uses TTY, save their number in contacts marked "TTY", which will help you remember to turn on the mode before calling.

Teletype problems on Xiaomi Redmi 9T and their solutions

When using TTY on Redmi 9T, users may encounter a number of challenges, including the most common ones and ways to fix them:

If after turning on TTY calls stopped working at all, try:

1. Turn off TTY and restart the phone.
2. Reset network settings in Settings → SIM-maps and mobile networks → Resetting network settings.
3. Contact Xiaomi or your carrier support team.

⚠️ Attention: In mode TTY Redmi 9T It can be discharged faster because the communication module is operating in a non-standard mode.

Alternatives to Teletype on Xiaomi Redmi 9T

If TTY doesn’t work for you for some reason, consider alternative ways to text:

• 📱 Subtitled video calls: Apps like Google Duo or Zoom support automatic speech-to-text decoding.
• 💬 Voice messaging: Telegram and WhatsApp allow you to send audio messages, which can then be listened to at a convenient time.
• 🆘 Specialized applications: For example, Rogervision TTY TextNow offers advanced features for people with hearing impairments.
• 📞 Relay services: Some countries have services that translate voice to text and back in real time.

The advantage of these alternatives is that they don’t require special settings on the phone and often offer more features (like real-time speech-to-text translation), but they all depend on the availability of the internet, while TTY operates over a standard telephone network.

Security and privacy when using TTY

Like any communication technology, teletype has its own nuances in terms of security:

• 🔒 Lack of encryption: Text messages TTY They are transmitted in open form over a voice channel, so they can be intercepted by attackers with access to the telephone line.
• 📡 Vulnerability to wiretapping: Telecom operators can technically view TTY-communications if required by law.
• 🚫 Limited authentication: Unlike messengers, the TTY no confirmation of the identity of the interlocutor – you can contact any number that supports the mode.

To minimize the risks:

• 🔐 Don't pass it through. TTY confidential information (passwords, card data).
• 📵 Use it. TTY only with verified subscribers.
• 🛡️ For important conversations, prefer end-to-end encryption messengers (Signal, WhatsApp).

If you need to communicate with government agencies or banks on TTY, ask them if they support secure channels, and some organizations provide special numbers for secure text calls.

💡

TTY is convenient for emergency communication, but not for sensitive data. Use secure messengers for confidential conversations.

FAQ: Frequent questions about teletype on Xiaomi Redmi 9T