The situation when access to the mobile data is lost during a voice call on a smartphone is familiar to many owners of devices based on Android. You start a conversation, and the indicator 4G or 5G changes to 3G or E, which makes it impossible to use the navigator or view messages in the messenger. This is not a breakdown of your gadget, but is a specific feature of the operation of cellular networks and algorithms for switching communication modes.
The main reason lies in the architecture of data and voice transmission. Traditional networks of the second and third generations were not designed for the simultaneous transmission of two streams of information over one frequency channel without reducing quality. When you initiate a call, the phone's modem redirects resources to the voice channel, temporarily blocking or severely slowing down the data channel. However, modern technologies make it possible to solve this problem if you configure the equipment correctly.
In this material we will analyze in detail the technical nuances of the operation of networks GSM, UMTS and LTE, and also provide step-by-step guide for activating a function that will keep your Internet active during a call.
Technological limitations of 2G and 3G
Historically, voice and data communications used different signal encoding technologies. In second generation networks (2G), voice is transmitted through circuit switching channels (Circuit Switched), while the Internet requires packet switching (Packet Switched). Old standards, such as GPRS and EDGE, were physically unable to support both types of traffic at the same time with sufficient speed.
With the advent of third generation technologies (3G or UMTS), the situation has improved slightly due to the advent of technology. HSPA+. It theoretically allowed voice and data to be combined, but in practice this often led to a significant drop in page loading speeds or dropped connections if the signal was unstable.
⚠️ Attention: If your smartphone automatically switches to 3G or 2G when making a call, this means that there is no fourth-generation network coverage for voice calls in your area, or the VoLTE function is not activated on your phone. operator.
Many users do not know that even if there is an icon 4G on the screen, the call itself can be processed using old protocols if the operator has not implemented the appropriate updates in its infrastructure. In such cases, the modem is forced to perform the so-called CSFB (Circuit Switched Fallback) - returning to 2G/3G networks to make a call, which inevitably interrupts the Internet session in LTE.
- 📶 2G networks use separate channels for voice and data.
- 📉 3G technology allows you to combine traffic, but the Internet speed drops sharply.
- 🔄 CSFB mode forces the phone to temporarily leave the 4G network for the sake of a call.
Solving the problem through VoLTE technology
The only effective way to maintain high-speed Internet during a call is to use technology VoLTE (Voice over LTE). This technology allows you to transmit the voice stream in the form of regular data within the fourth generation network. Thus, for a smartphone, a call is no different from browsing a web page or making a video call in WhatsApp.
When active VoLTE the connection does not switch to 3G, and you can simultaneously talk on the phone and download files at the maximum available speed. However, for this function to work, three conditions must be met: your smartphone supports the technology, the service is available from your telecom operator, and the setting is enabled in the device menu.
It is worth noting that not all tariff plans include this option by default. Some operators require you to connect an additional service or switch to a modern tariff. Also, the quality of communication directly depends on the signal level: with poor coverage LTE the phone can still drop the call in 3G to maintain voice stability.
To check VoLTE support, enter the code in the engineering menu ##4636## and select "Phone Information". If there is a VoLTE Provisioned switch there, your device is technically ready for use.
How to enable VoLTE on different Android models
Activation of the function may vary depending on the manufacturer's shell and operating system version. In most modern smartphones, the setting is located in the mobile network section. You need to go to Settings → Connections → Mobile networks and find the item Calls via LTE or VoLTE.
On devices Xiaomi i Redmi sometimes this item is hidden. To display it, you may need to enter a special command through the app Engineering menu or use hidden codes in the dialer, for example ##86583##, which forces the operator to check whether the function is supported.
If standard methods fail to enable the option, you can try resetting the network settings. This will not delete your personal data, but will return the connection settings to factory defaults, which often helps eliminate software conflicts.
⚠️ Attention: After resetting the network settings, you will have to re-enter the passwords for Wi-Fi networks and Bluetooth device pairs. Make sure you remember the data for accessing your home Internet.
☑️ Checking readiness for VoLTE
Network mode settings and preferred type
Often the problem is solved by simply changing the priority of network types. If the “Only 3G” or “2G/3G” mode is selected in the settings, then the Internet during a call in high quality is out of the question. It is necessary to set the value LTE/3G/2G (auto-connection).
In some cases, manually switching the network mode helps. Try temporarily selecting "LTE Only". If after this calls become impossible (they will be dropped immediately), this will confirm that there is no VoLTE voice coverage in your location, and the phone is correctly trying to switch to 3G for connection.
For advanced users, access to the hidden menu of the radio module is available through the code ##4636##. In the Phone information section you can find the drop-down list "Configure your preferred network type". Selecting the option LTE Only may force you to keep the Internet, but remember the risk of complete loss of voice communication.
| Network mode | Internet during a call | Voice quality | Stability |
|---|---|---|---|
| 2G / 3G (auto) | No or very slow | Low | High |
| LTE / 3G / 2G | Yes (with VoLTE) | HD (high) | Depends on coverage |
| LTE only | Yes | Absent (no VoLTE) | Low (no calls) |
| 5G / LTE / 3G | Yes (VoNR / VoLTE) | Ultra high | Requires new software |
What if the VoLTE item is not in the menu?
If there is no VoLTE switch in the standard settings menu, this does not always mean that the phone does not support the function. Often operators hide this option for devices that have not passed their certification. Try installing a switch app from the app store or change the region in your phone settings to a country where your operator officially supports VoLTE (for example, India or the USA for some models).
The influence of the telecom operator and tariff plan
Even the most powerful flagship smartphone will not be able to provide Internet during a call if the telecom operator does not support this technology in your region. Large federal operators have long implemented VoLTE, however, in remote areas, towers may operate in an outdated mode.
In addition, some budget tariff plans may artificially limit the ability to use packet data simultaneously with voice traffic. The terms of the contract sometimes stipulate that high-speed Internet is available only in standby mode.
It is recommended to contact the support service of your operator or check your personal account. Often there is a checkbox “Activate VoLTE” that needs to be checked manually. Without this step, the network will ignore your phone's requests to establish a voice channel via LTE.
The presence of a 4G icon on the screen does not guarantee that the Internet will work during a call. It is critical that the operator supports voice transmission over this network (VoLTE).
Alternative solutions and instant messengers
If technical methods cannot solve the problem, it is worth considering alternative methods of communication. The use of Internet instant messengers, such as Telegram, WhatsApp or Viber, allows you to make voice and video calls exclusively through a data channel.
In this case, even if the network switches to 3G, the conversation will not interrupt the transmission of Internet traffic, since the conversation itself is part of this traffic. The only downside is that you spend minutes or gigabytes from your tariff plan, unlike regular minutes, which are often unlimited.
You can also use the function Wi-Fi Calling. If your phone and carrier support this technology, you can make regular calls over your home Wi-Fi network. In this case, the mobile data may be turned off completely, or you can use mobile data in parallel if the phone supports two radio modules or has the function of simultaneous operation of Wi-Fi and mobile data.
⚠️ Attention: Calls via instant messengers require a stable connection. With a poor 3G signal, the sound quality will be significantly worse than with a regular voice call through the operator's network.
Frequently asked questions (FAQ)
Why does the Internet work on one phone during a call, but not on the other?
This depends on the support of VoLTE technology by the specific device and the operator’s settings. If one phone is certified by the operator to work in a 4G network with voice, but the second is not (or the function is disabled on it), then the second will reset the Internet when making a call.
Does turning on airplane mode affect this problem?
Airplane mode completely turns off all radio modules, so there will be no calls or Internet. However, briefly turning airplane mode on and off can help reconnect to a tower with a better signal, which will indirectly improve the situation.
Can I flash my phone to get VoLTE support?
Theoretically, yes, installing custom firmware or modified software can unlock hidden modem functions. However, this is a complex process that may void the warranty and cause unstable operation of the device. This method is not recommended for beginners.
Will the Internet work during a call on 5G networks?
Yes, fifth generation networks use technology VoNR (Voice over New Radio), which is an analogue of VoLTE for 5G. It provides even higher speed and quality of communication, allowing you to simultaneously use all the capabilities of the network.
Why did the Internet disappear when making a call after updating Android?
The system update could reset the network settings or change the algorithm for working with the operator. Check if the VoLTE checkbox was disabled in the settings after the update, and if necessary, reconnect the service with the operator.