Xiaomi Teletype (TTY) Mode: A Complete Guide to Setup and Application

Have you ever noticed the mysterious “Teletype Mode” (or TTY Mode) in your Xiaomi settings and wondered what it was for? A feature inherited from older analog phones still exists in modern smartphones — but not all users understand its purpose. In the era of instant messengers and video calls, teletype seems anachronistic, but it remains a critical tool for people with hearing or speech impairments.

In this article, we will understand what a regime is. TTY How to turn it on or off on different models (from Redmi Note 12 to Xiaomi 14 Ultra), what types of teletype exist, and why this feature can suddenly activate on its own. You will also learn how to solve typical problems, from the lack of sound when calling to the errors of connection to the networks of operators. TTY-devices, this guide is for you.

What is Teletype Mode (TTY) and Why You Need It

TTY (Teletypewriter or Text Telephone) is a technology that allows you to send text messages over a phone line in real time, originally designed for people with hearing or speech impairments, so they can communicate on the phone by typing messages on a special device (teletype), which is a feature that is emulated software on modern Xiaomi smartphones, but the principle of operation remains the same:

📞 Voice. → Text: Your interlocutor is talking into a phone, and you see his words as text on the screen.
⌨️ Text → Voice: You type a message and the person hears it as synthesized speech.
🔄 Text ↔ Text: both subscribers communicate only by text messages (for example, if both are enabled). TTY).

In 2026, teletype is still relevant for:

🦻 People with disabilities (deaf, hard of hearing or having speech problems).
🏥 Medical and emergency services, where TTY used to communicate with patients.
📡 Amateur radio and military – in some cases, teletype is used to transmit data over analog channels.
🌍 Travelers in countries where mobile internet is not available but there are analogue telephone lines.

On smartphones Xiaomi mode TTY implemented at the firmware level MIUI It is supported by most models, from the Redmi 5 (2017) to the flagships of 2026, but in some regions (for example, in Russia), operators can block this feature at the network level, so its availability depends not only on the phone, but also on the phone. SIM-map.

📊 Have you ever used a regime? TTY?

Yeah, regularly.

I tried it once.

I've never heard of him.

I don't know what it is.

Types of TTY modes on Xiaomi: which to choose

In Xiaomi's settings, you can find up to four different teletype options, each designed for different use cases.

TTY mode	Description	When to use
TTY Off	Teletype is off, the phone is running in standard voice mode.	For regular calls without using TTY.
TTY Full	Full mode: both incoming and outgoing messages are transmitted as text.	If both parties are using TTY-device.
TTY HCO	Hearing Carry-Over: You hear the voice of the person you are talking to, but you respond with text.	For people who can hear but cannot speak.
TTY VCO	Voice Carry-Over: You speak, but you see the person’s response in the form of text.	For people who can talk but can’t hear.

Most of the Xiaomi smartphones, for example, POCO X6 Pro or Redmi 13C) default mode TTY Off. If you accidentally turn on a teletype and don't know how to return normal calls, just go to the settings and reset the setting. TTY-Standard voice calls may not work – instead of sound, you will hear a squeak or see an empty screen.

⚠️ Attention: If you have turned on TTY Full, but your interlocutor does not use teletype, the call can be interrupted in 10-15 seconds due to incompatibility of protocols. TTY Check with the subscriber whether his device supports this mode.

What happens if you turn on TTY on your smartphone without support?

On some budget models (e.g. Redmi) A2) activated TTY You can lose your network icons or your mobile data, and you can only reboot your phone or reset your network settings.

How to turn on or off TTY mode on Xiaomi

The instructions for activating the teletype depend on the version of MIUI and the model of the smartphone. Below is a universal algorithm that works on most Xiaomi, Redmi and POCO devices (including Xiaomi 13T, Redmi Note 12 Pro+ and others).

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On some models (for example, Xiaomi 12S Ultra) the path to settings may be different:

Settings → System → Advanced settings → Special features → TTY Mode

If you don’t see TTY on the menu, it could mean:

📵 Your operator does not support teletype (for example, Tele2 in Russia blocks this feature).
📱 You have an outdated version. MIUI (Update the firmware through Settings → The phone. → Updating the system).
🔧 The function is hidden in the engineering menu (available only for power users).

⚠️ Attention: After activation TTY Full, all incoming calls will be automatically received in text mode. TTY, You won't hear his voice, instead, the phone will make a long horn. To return normal calls, turn off the teletype in the settings.

💡

If, after activation, TTY mobile Internet is missing, try to manually select the operator network in the settings SIM-maps and mobile networks → Network selection: Sometimes the phone forgets the connection settings when switching modes.

Xiaomi’s TTY Mode Problems and Solutions

Despite the ease of customization, Xiaomi users often experience teletype errors, and here are the most common problems and ways to fix them:

Problem.	Possible cause	Decision
No sound when calling in TTY mode	Incompatibility with the operator or firmware error.	Switch to TTY Off or upgrade to MIUI.
The phone does not save the TTY settings.	Reset settings after rebooting.	Reset network settings: Settings → SIM-map → Resetting network settings.
When you call, you hear a squeak instead of a voice.	TTY Full is activated, but the interlocutor does not use teletype.	Turn off TTY or switch to TTY HCO/VCO.
The keyboard for entering text does not work	Error in the Phone app.	Clear the app cache: Settings → Apps → Phone → Memory → Clear the cache.

If none of the solutions worked, try resetting your network settings:

→ SIM-maps and mobile networks → Additional → Network reset

Some firmware (e.g. MIUI Global for Xiaomi 11T) may require mobile data to be re-activated after the reset, and check if your carrier is blocking TTY, contact support and check if the teletype is supported on your tariff.

💡

After inclusion TTY phone stopped catching the network, try manually selecting the communication standard (2G/3G/4G) customized SIM-Teletype only works on networks. GSM, So, it's an automatic choice. LTE may interfere with his work.

TTY on Xiaomi vs. Other Ways to Text Call

Teletype mode isn't the only way to text on the phone. In 2026, Xiaomi users have alternatives that might be more convenient than TTY.

📱 RCS-Google Messages: Allows you to send SMS with proof of reading and files, but require the Internet. TTY It works without a network connection.
💬 WhatsApp, Telegram: More convenient for everyday communication, but useless in emergency situations (for example, when calling the rescue service).
📞 Video calls with subtitles: in MIUI 14+ Speech recognition is available, but it requires a stable internet connection.
🆘 Emergency. SMS: In some countries (such as the United States) it is possible to send SMS 911, but this service is not supported in Russia.

The main advantage of TTY over alternatives is that it works without the Internet, which is critical in situations where:

🏔️ You are in an area without coverage. 4G/LTE, but there's a signal 2G.
🚨 You need to contact the rescue service, and voice communication is not possible.
🔋 The battery is down and the phone is running in savings mode (TTY It consumes less energy than messengers).

However, the teletype has drawbacks:

⏱️ Slow text transfer (about 50 characters per minute vs. 1000)+ messenger-wise).
🔠 Limited character set (no emoji, formatting, pictures).
📶 Dependence on operator support (not all providers provide support) TTY-service).

💡

If you need a text call but TTY doesn't work, try using Google Live Transcribe, which recognizes the speaker's speech and displays it in real time, even without the Internet (after preloading the language packets).

How to check if your Xiaomi supports TTY

Not all Xiaomi models support teletype. To see if this feature is available on your device, follow the following steps:

Open the phone app and dial the combination: ##4636##.
In the menu that appears, select Phone Information.
Scroll down and find the TTY Mode string, and if it's not there, your smartphone doesn't support teletype.

You can also check TTY support through the engineering menu (works on most Qualcomm-based devices):

Settings → About Phone → MIUI Version (Tap 7 times to activate Developer Mode) → Return to Settings → Additional → For Developers → Engineering Menu → Engineering Menu (MTK) → Telephony → TTY Settings

If none of these things worked, your device either doesn't support TTY or it's blocked by firmware.

🔄 Update MIUI Up to the latest version (sometimes support) TTY added in new assemblies).
📲 Install custom firmware (such as LineageOS) if you are an experienced user.
📞 Call for Xiaomi Support with Support TTY for your model.

⚠️ Note: On smartphones with MediaTek processors (e.g. Redmi) 10A or POCO M5) The engineering menu may not contain any settings TTY. In this case, check the presence of the function through the standard settings of special features.

The future of the TTY mode: will it remain in the smartphones Xiaomi

With the development of technology, teletype mode is gradually becoming a thing of the past: in 2026, many operators (including MTS, Beeline and MegaFon) no longer provide TTY services, and in new smartphones this feature is often hidden or removed.

🌍 Global Standards: in the US and Europe TTY It is mandatory for devices certified to accessibility standards (e.g, ADA or EN 301 549).
🆘 Emergency services: in some countries (e.g. Canada) 911 calls TTY treated with priority.
🔄 Backward compatibility: old ones TTY-The devices are still used in hospitals, banks and government agencies.

However, there are already trends to replace TTY with more modern solutions:

📡 Wi-Fi Calling with subtitles: in MIUI 15 (expected 2026-2026) may have built-in voice recognition for Wi-Fi calls.
🤖 AI assistants: Xiaomi is testing HyperOS Voice technology that will automatically convert voice to text and back.
📶 5G VoNR: New communication standards allow real-time text messages to be transmitted without any need for a TTY.

If you don't use teletype, you can turn it off in the settings. However, on some models (such as the Xiaomi Mix Fold 3), TTY activates automatically when you connect to certain networks - this is a feature of the firmware, not a bug, in which case only manual shutdown will help.

💡

Even if TTY disappears from mainstream smartphones, it will remain in specialized devices (such as phones for the elderly or emergency equipment).

FAQ: Frequent questions about Xiaomi’s TTY mode

❓ Why my Xiaomi is not in the mode TTY?

This may be due to: outdated version of MIUI (update firmware); lack of operator support (check with provider); regional restrictions (in some countries TTY is disabled by default); hardware restrictions (budget models on MediaTek Helio may not support TTY); Try checking for a feature through the engineering menu (instruction above).

❓ Can I use it? TTY for international calls?

Technically yes, but in practice it depends on: TTY Roaming for text calls (not all tariffs include it) Compatibility of standards (in Europe and the United States different protocols are used) TTY). Before calling, check with your operator whether international support is available. TTY-challenge.

❓ Why not after the switch on TTY Mobile data is not working?

This is a typical problem when switching between modes of communication. Solutions: Reboot your phone. Manually select the network. 3G (TTY often not working 4G/LTE). Reset network settings in Settings → SIM-map → Reset network settings. Update firmware through Settings → The phone. → System Update. If the problem persists, contact Xiaomi for support with the phone model and version. MIUI.

❓ How to turn off TTY, if he's on his own?

Automatic activation TTY It can happen after: Firmware updates. Changes SIM-Cards (some operators are forced to include) TTY Reset the settings to factory. To turn off: Settings → Special facilities → Rumor → Regime. TTY → Choose "TTY Off" If the item is missing, try resetting the network settings or returning the phone to factory settings.

❓ Can I use it? TTY send out SMS?

No, TTY and SMS are different technologies. TTY is real-time during a call, and SMS is a separate text messaging service, but in some countries (like the United States) there is TTY Relay, which allows you to send text messages to an operator, and the operator sends them by voice to an interlocutor.