What does the HD icon on Xiaomi Redmi mean when you call?

Modern smartphones Xiaomi Redmi and POCO line equipped with advanced voice technology, which users often learn by accident. at the top of the screen, next to the network indicator or subscriber number, can appear mysterious inscription HD. Many gadget owners ignore this symbol, considering it a standard element of the interface, which has no practical value.

But this icon is a stepping stone to a whole new level of voice communication, not just a marketing ploy, but a real technology that changes the acoustic experience of a conversation, and understanding what HD means on a phone will help you enjoy your conversations without echoing, interrupting, and the metallic timbre of your voice.

In this article, we will discuss in detail the technical nature of the technology, how it is activated on devices with the shell MIUI and HyperOS, and how to solve problems if the icon never appeared, you will learn why carriers implement this standard and how it affects the traffic consumption and battery charge of your smartphone.

The Technology Essence of HD Voice

HD stands for High Definition, which literally means "high resolution." If it's the number of pixels in the screen, then telephony is the frequency of the sound signal. Traditional cellular (2G/3G) uses a narrowband codec that cuts frequencies below 300 Hz and above 3400 Hz. That's why voices in older networks sound deaf and indistinct, especially in noisy environments.

HD Voice technology, which runs on top of 4G (LTE) and 5G networks, extends that range to 50 to 7,000 Hz and above, allowing the full spectrum of human voice to be transmitted, including low bass tones and high whistling sounds, making speech natural, eliminating the barrel-talk effect, and increasing the legibility of words even when there is background noise.

⚠️ Attention: Availability of a badge HD It does not guarantee perfect communication if you are in the zone of uncertain reception of the signal. 4G. Technology requires stable data channel for high quality codecs.

It is important to understand that this feature requires support from all participants in the chain: your smartphone, SIM-The card, the operator base station and the interlocutor's phone, if at least one link does not support the VoLTE standard (Voice over). LTE), The connection will automatically roll back to normal quality, and the icon will disappear.

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For maximum sound quality, both interlocutors must be in the coverage area. 4G/LTE and have an activated service HD-caller.

The difference between VoLTE and traditional voice communication

Often users confuse just having a 4G network for the Internet and being able to make voice calls through that channel. Standard technology assumes that when a phone calls in or out, it temporarily switches to 3G or 2G mode. At this point, the Internet speed drops to a minimum or the connection is completely cut off, which is because older networks can't simultaneously transmit voice and data at high speeds.

VoLTE Technology (Voice over) LTE) This problem is solved by packing the voice stream into IP-Packages, just like instant messengers like WhatsApp or Telegram do, but with priority on the operator's network, so that during a conversation, your Xiaomi Redmi continues to work at full speed on the Internet. You can send files, watch the navigator or flip through the feed of social networks without losing sound quality.

In addition, VoLTE provides a much faster connection, the dialing time to the beeps is reduced from 5-7 seconds to 1-2 seconds, which is because the smartphone does not need to spend time rearranging the radio module between communication standards.

• 📶 Simultaneous work: Internet 4G/5G It works at full speed even when talking.
• 🔊 Sound quality: A broadband audio codec is used to transmit pure and natural sound.
• ⚡ Connection speed: Instant dialing without long waits for connection installation.

It’s worth noting that switching to VoLTE also has a beneficial effect on power consumption: the smartphone doesn’t have to constantly jump between 2G/3G/4G modes, which reduces the load on the processor and radio module. However, if the LTE signal is weak, the phone will waste more energy on its retention, which can lead to a faster discharge.

How to enable HD Voice on Xiaomi Redmi

Most modern models Xiaomi and Redmi function HD Voice is enabled by default if it's supported by the operator and firmware, but in some cases, especially when using two. SIM-If you have a map or reset, you have to activate it manually, and the setup process is fairly simple, and you don't need to get root permissions.

First, make sure that yours is yours. SIM-card 4G and VoLTE is on the carrier side (more on this in the next section). Then go to your device's settings menu. The path may vary slightly depending on the version. MIUI, But logic remains the same.

In the menu that opens, find the item related to the choice of network type, usually called "Network type of preference." Make sure you choose the option "Preferred 4G" or "5G preferably." Below should be the switch "Use VoLTE" or "LTE calls." Once activated in the notification curtain or near the network indicator, the corresponding icon should appear.

If you don't see the VoLTE switch, it may be hidden in the engineering menu or blocked by the operator. Some firmware requires you to enter a special code in the "bell ringer" or use the Engineering Mode application to activate it. However, on global firmware versions of Global ROM, this switch is usually open access.

⚠️ Note: When you turn on VoLTE on the second SIM-Desktop card (Dual) SIM Dual Standby – One of the cards may temporarily lose the ability to accept calls in the format 2G/3G, If the phone does not support DSDS Full VoLTE on both slots.

Operator requirements and tariff plan

Having a powerful Xiaomi smartphone with support for all frequencies is only half of the success. A critical condition is the support of the technology by your mobile operator. In Russia and CIS countries, all major providers (MTS, Beeline, MegaFon, Tele2) have already implemented VoLTE, but the service may not be activated at your default tariff.

Often, operators require that SIM-The card has been replaced with a new one if you use very old plastics made before the era. 4G. It is also necessary to have coverage in your area. LTE. Even if there is a city 4G, In a particular building or basement, the signal can only be 3G, shutdown HD-regime.

Remember that traffic during the HD-It's not usually charged as Internet traffic, it's not subtracted from the main gigabyte package, it's counted in minutes of your plan. However, if you make a video call through a native feature (if supported), the data consumption can be significant.

Impact HD-battery calls and traffic

One of the most common questions users ask is, “Does HD put down a battery faster?” The answer is ambiguous. On the one hand, high-quality voice requires more processing power to encode and decode sound. On the other hand, the lack of constant switching between 2G/3G/4G allows the radio module to operate in a more stable and energy-efficient mode.

In a 4G signal receiving environment, HD Voice can even extend battery life compared to the constant jumps between communication standards. However, if the LTE signal is weak (1-2 division), the phone will constantly increase the transmitter power to connect, which will lead to accelerated discharge. In such situations, the HD icon can often disappear and reappear, causing additional energy consumption.

As for traffic, VoLTE voice calls consume about 3-4 MB of data per minute. That's not much, but if you have a limited packet of Internet and you don't have a VoLTE exception set up in the system, theoretically, those megabytes can be consumed, but in practice, operators flag that traffic with a special flag, and it's not charged.

• 🔋 Energy savings: In the area of confident reception 4G battery is spent more economically due to the lack of switching networks.
• 📉 Consumption in a bad signal: with a weak signal LTE Energy consumption increases due to increased transmitter power.
• 🌐 Traffic: Consumes Internet channel, but is not usually charged by telecom operators.

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In a stable environment 4G covering HD-calls are more cost-effective for the battery than constant reconnection between 2G and 3G.

Typical problems and ways to solve them

Despite the technology's fine-tuning, Xiaomi Redmi users may experience situations where the HD icon doesn't appear or the connection is constantly disrupted. Often the problem lies in the APN settings. If the Internet settings are set incorrectly, the phone will not be able to set a priority channel for voice.

Try resetting your mobile network settings. Go to Settings → Connection & Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Note that this action will remove saved passwords from Wi-Fi, but often solves problems with registering on the VoLTE network.

Another reason may be firmware incompatibility: on Chinese versions of smartphones (China ROM), the list of supported operators is limited. If you use such firmware with a SIM card from another region, the function may not activate, in which case changing the region in the settings (Settings → Additional → Region) to the country of your operator (for example, Russia or Ukraine) helps.

⚠️ Warning: If after all the manipulations the icon did not appear, check whether the mode is not "Traffic Saving" or "Flight Mode" with a resolution only for Wi-Fi. These functions block the transmission of voice data through the Internet. LTE.

In rare cases, the problem can be physical — damage to antenna contacts inside the smartphone after a fall. If other devices with the same carrier’s SIM card HD works, and yours does not, you may need to diagnose the hardware part.