Cell Broadcast Service on Xiaomi: everything you need to know about emergency SMS-warning

If you’ve ever received a strange message on your Xiaomi smartphone with a loud signal that can’t be deleted or ignored, chances are it worked (CBS). This technology, built into modern phones, is designed to provide mass emergency alerts, from natural disasters to terrorist attacks. But how does it work on Xiaomi devices, can it be turned off, and why is it not always a good idea.

Many Redmi users, POCO or Mi encounters CBS It's random, like when you're traveling abroad, when the phone suddenly makes a shrill sound and gives a full-screen alert, and others only learn about the function when they set up a new device, noticing an unknown item in the message menu. In this article, we will explain what Cell Broadcast Service is, how it is implemented in firmware. MIUI, Why it’s best not to ignore it, even if it seems annoying.

Cell Broadcast is not the usual SMS It's a separate communication channel that governments and rescue services use to alert the public, and in some countries (such as the United States, Japan or the Netherlands), such messages are mandatory to read, and blocking them may be illegal. But how it works in practice – read on.

What is Cell Broadcast Service and Why You Need It?

Cell Broadcast (CBS) — It's a technology for mass texting to all mobile devices in a particular geographic area. SMS, which are sent to a specific number, CBS-And that's what makes it ideal for emergency alerts when you count for seconds.

Main use cases:

• 🚨 Natural hazards: tsunami, earthquake, hurricane or flood warnings, such as in Japan, the J-Alert system uses the CBS alerting for approaching typhoons.
• 🚔 Emergency situations: terrorist attacks, riots, chemical accidents. In the United States, it's part of the Wireless Emergency Alerts system (WEA).
• 📢 State Notifications: Quarantine Measures, Evacuation Calls, Important Legislation Changes.
• 🚗 Road Alerts: In some countries CBS Used to warn of traffic jams, accidents or closed sections of roads.

It’s important to understand that Cell Broadcast is independent of the internet – messages are transmitted via cell towers, so they work even when there is no mobile network or Wi-Fi, which is critical in disaster areas where communication is often overloaded or disconnected.

On smartphones Xiaomi support CBS firmware-level MIUI. The function is activated automatically if the mobile operator supports it, for example, in Russia, such alerts were tested in 2020-2023, but were not widely implemented (except in certain regions). CBS It is used actively – so travelers often encounter unexpected signals on the screen.

How Cell Broadcast works on Xiaomi: technical details

Technology CBS standard-based 3GPP TS 23.041, which defines a protocol for short messages over cellular networks. SMS, stored SIM-In the card or in the phone’s memory, Cell Broadcast messages are not saved – they are displayed immediately on the screen and disappear after reading (or after a predetermined time).

On Xiaomi smartphones processing CBS The system application CellBroadcastReceiver, which is part of the MIUI. It works in the background and does not require a separate setup – however, it can be turned on or off manually (more on that later).

Key features of implementation on Xiaomi:

• 📶 Support for multiple channels: CBS can be broadcast on different frequencies (e.g., channel 50 for emergency alerts, channel 919 for test messages).
• 🔊 Priority Audible Signal: Messages are accompanied by a loud sound that cannot be turned off through the volume control (it uses a separate audio channel).
• 📱 Display over all windows: CBS-A warning appears even if the phone is locked or another application is running.
• 🌍 Geolocation: only devices that are within range of a particular tower receive a message.

Interesting fact: some Xiaomi models (e.g. Redmi Note 10 Pro or Xiaomi) 12T) CBS-messages can be duplicated in the notification section, even if they cannot be manually deleted, so that the user does not miss important information.

How to turn Cell Broadcast on or off on Xiaomi

Default function CBS It's activated on all Xiaomi smartphones, but it can be turned off -- although we don't recommend doing it for no good reason. MIUI, But the general algorithm is:

For MIUI 12/13/14:

1. Open the Messages app (an envelope icon).
2. Slip on three dots in the upper right corner and select Settings.
3. Scroll down and find the Emergency Alerts or Cell Broadcast section (the name may vary).
4. Turn on or off the switch next to Accept Alerts.

For older versions of MIUI (up to 12):

• Go to Settings. → Annexes → Communications → Additionally.
• Find Cell Broadcast and manage channel settings.

⚠️

Note: In some countries (such as the United States or Japan) shutdowns CBS You may be prohibited by law. Please check local regulations before changing your settings.

If you can't find the Cell Broadcast section in the menu, your carrier may not support this feature, or it's hidden in the regional firmware, and then you can try activating it through the engineering menu codes:

#4636## → Test menu → Phone settings → Cell Broadcast

But beware: improper actions in the engineering menu can disrupt the network.

Open “Messages"|Find the section "Emergency alerts"|Make sure the function is enabled|Check for test messages (if available)-->

Which Countries Does Xiaomi Support Cell Broadcast?

Functionality CBS It depends not only on the smartphone, but also on the mobile operator and local legislation. Here is a table of data on the key countries where Xiaomi officially supports emergency alerts:

The EU-Alert Directive has been in force since 2022, obliging operators to support the EU’s efforts to CBS This means that even if you bought the phone in Russia, you will receive local alerts when traveling to Germany or France.

In Asia (for example, Thailand or Indonesia) CBS It's often used to warn of tsunamis or wildfires, but in Africa and Latin America, the technology is not widely available because of the lack of infrastructure.

⚠️

Note: If you buy Xiaomi in a secondary market (such as one imported from China), check if it supports it. CBS Some gray models may have limited functionality.

Cell Broadcast Issues on Xiaomi and How to Solve Them

Thought CBS — And because of the technology that's reliable, Xiaomi users sometimes have problems, and these are the most common ones and the ways that they can be addressed:

1. no emergency alerts are coming in

• 🔄 Check if the function is enabled in Message settings.
• 📶 Make sure your operator supports you. CBS (The list can be specified on its website).
• 📱 Update the firmware MIUI Up to the latest version – in old builds can be bugs.
• 🌐 If you are on roaming, some countries will block CBS foreign SIM-map.

2.The messages are duplicated or do not disappear

This is a well-known bug in some versions. MIUI Decisions:

• 🗑️ Restart your phone – sometimes it helps clear the notification cache.
• 🛠️ Reset the Messages app settings in Settings → Annexes → Communications → Warehouse → Drop it.
• 📲 Install an alternative application for SMS (Google Messages, which can be handled better CBS.

3. Loud sound cannot be turned off

Most countries sound CBS You can't adjust or disable it, it's for your safety, but in some regions (where alerts are not mandatory), you can try it:

• 🔇 Put your phone in silent mode before receiving a message (sometimes it works).
• 🎵 Use notification blocking apps (such as Notification Blocker) but this could break the law.

If the problem persists, contact Xiaomi support or your carrier – you may need to flash the device.

💡

Before traveling abroad, check if your Xiaomi supports locals. CBS-You can send a test message via the engineering menu (#4636##) or contact the operator.

Cell Broadcast vs. Other Alert Systems: Which Is Better

CBS — It's not the only technology for emergency notifications, but let's compare it to alternatives to see why it remains standard in most countries.

Main advantage CBS — Internet independence and network congestion, and during natural disasters, mobile operators are often overloaded. SMS But Cell Broadcast uses a separate channel, which is always free.

However, the technology has disadvantages:

• ❌ Limited text size (typically up to 1,395 characters, but more often messages up to 93 characters).
• ❌ No way to respond or request additional information.
• ❌ In some countries CBS used for spam (e.g. advertising from operators).

Alternatives are also available on Xiaomi smartphones:

• 📱 Annex “Security” (included in MIUI) — May show local weather or emergency warnings.
• 🌍 Google Public Alerts is a service from Google that sends notifications over the Internet (works on Google Messages).

💡

Cell Broadcast is the most reliable system for emergency alerts, but its effectiveness depends on operator support and local legislation, and works out of the box on Xiaomi, but may require manual configuration in some regions.

Cell Broadcast’s Future: What the Technology Will Look Like

Despite the fact that CBS It's been around since the 1990s, and it's been evolving, and it's been being integrated with modern communication standards, like this. 5G and LTE-M (for IoT devices. Here are the key trends:

1. Expansion of functionality

• 📊 Support for multimedia messaging (images, maps, videos) – already being tested in Japan and South Korea.
• 🗺️ More accurate geolocation through integration with GPS and Wi-Fi.
• 🔄 Bilateral communication: the ability to confirm receipt of a message or request assistance.

2.Integration with smart devices

In the future. CBS Not only will they be able to get smartphones, but they will also:

• 📺 TVs (e.g. Xiaomi Mi) TV) — display warnings on the big screen.
• 🚗 Automotive systems (such as Android Auto) – to alert drivers.
• ⌚ Smartwatches (such as Xiaomi Watch) S3) — vibrator.

Global standardization

Organizations like GSMA and ITU working on unification CBS It means that in the future:

• 🌎 The alerts will be automatically translated into your phone language.
• ⚡ The number of false positives will decrease.
• 📡 Improved coverage in remote areas.

For Xiaomi owners, this means that new models (such as Xiaomi 15 or Redmi Note 14) feature the new Xiaomi model. CBS It will be expanded. There may be separate settings for different types of alerts (for example, you can turn off advertising messages, leaving only emergency ones).

FAQ: Frequent questions about Cell Broadcast on Xiaomi