How to increase the duration of the call on the phone Xiaomi

Xiaomi, Redmi and Poco smartphone owners often experience a conversation interruption after exactly 4 hours or even 15 minutes, despite having a stable signal and battery charge. This is a common problem that can be caused by both the software limitations of the MIUI or HyperOS shell, and the rigid tariff plans of your mobile operator. Understanding the nature of the restriction is the first step to successfully eliminating it. In most cases, the solution lies not in deep system settings, but in specific codes or network parameters.

There are several levels of call locking: The first level is a hardware timer that could theoretically be present in the firmware to protect against overheating of the communication module, although this is extremely rare in modern models; the second, and more likely, level is a software ban on the part of the cell tower. Communication operators implement such limits to unload networks or force the termination of connections charged under special conditions. The third level is the settings of the phone application itself, where energy saving functions or background activity restrictions can be activated, which are mistakenly interpreted as the end of the call.

Before you start to manipulate the engineering menu or flashing, you need to rule out the trivial reasons, check if you have an automatic forwarding to voicemail or another number that works on a timer. SIM-The card is not activated mode "Only" 3G» or "Only" 2G», Because the old communication standards are less stable with long-term channel retention, call duration is a multi-factorial parameter, and a systematic approach to diagnosis can save time.

Checking the settings of the mobile operator and tariff

The most common reason for abrupt interruption is your carrier’s policy. Many plans, especially archival or specialized ones (for example, for IoT devices or enterprise packages with a limit of minutes), have a built-in limiter. It can be 15 minutes, 1 hour or 4 hours. To find out the exact limit, it is best to contact support or check your personal account, but there are also technical methods of diagnosis.

Sometimes the operator imposes a service called Anti-AON or Secretar, which can conflict with long connections, and it is also worth checking whether the numbering service is activated, which in rare cases can cause a gap when changing a base station during a long conversation. If you use VoLTE (Voice over LTE), try to temporarily disable this feature, since some operators incorrectly handle long sessions of VoIP telephony on their networks.

⚠️ Note: If your carrier has set a tight network-level call time limit, you can't change that through your phone's settings, and only changing the tariff or switching to another provider will help.

To check for current redirect settings that may affect duration, use standard redirects. USSD-codes. They're universal for most networks. GSM:

• 📞 *#21# – Checking the status of all types of forwarding.
• 📞 *#61# – Checking for forwarding if the subscriber does not respond (important for timeouts).
• 📞 *#62# – Checking for forwarding if the subscriber is unavailable.
• 📞 ##002# – Complete cancellation of all redirects (may require confirmation).

Use of engineering menus and hidden codes

Xiaomi smartphones have a hidden engineering menu that allows you to access the settings of the modem and radio module. This is where you often find parameters that affect the stability of the connection and its duration. However, be extremely careful: changing unknown parameters can lead to loss of signal or inoperability of the communication module.

Most devices with MediaTek and Qualcomm processors use the code ##3646633## or ##4636##. If the standard code doesn't work, your version of MIUI may be blocking access and you'll need to install a special activator application from third-party sources, although this is not recommended for security reasons.

Inside the engineering menu, we're interested in the Telephony tab or Network Selecting. Here you can try to force the network mode to switch. For example, if you have "Auto", try to lock in "WCDMA only" (3G) or "LTE only." Sometimes fixing on a certain communication standard eliminates micro-gaps that accumulate and lead to a complete call break. Also in the BandMode section you can deselect rare frequencies that your phone tries to "catch" during a conversation, losing the main signal.

There is also a specific code for resetting call settings that can help if the problem is caused by a software glitch in the profile. SIM-map:

##72786#

This code (SCRTN — Special Code To Reset The Network) resets the network settings to factory settings, and once it is applied, the phone will reboot, and you will have to re-enter some settings if you manually required them.

Setup of the application “Phone” and system restrictions

The MIUI shell is known for its aggressive energy-saving system, which can kill telephony if it finds it too resource-intensive or time-consuming, especially for models with little RAM, and to eliminate this factor, you need to prioritize your system application.

Go to Settings → Applications → All Apps and find Phone (or Calls, depending on the MIUI version and region). Go to Battery or Power and select No Limits mode. This will prevent the system from interrupting the application to save charge. It is also useful to clear the cache of this application through the Memory menu, as accumulated error logs can cause conflicts.

Another important point is the use of noise cancellation. In some regions (India, Indonesia), Xiaomi firmware has a 2-hour limit for calling to combat telemarketing. If you are in a region like this or use a global firmware with regional settings, this restriction can be hard-wired, bypassing it by changing the region in the phone settings to Andorra or Nepal, where there are no such restrictions, or by installing a third-party call.

The 4-hour limit problem and its solution

There is a widespread myth and a real technical feature of GSM/UMTS/LTE networks, the so-called “4-hour timer.” Mobile protocols were originally designed to ensure that a normal conversation does not last more than a few hours. The counters in operator switches often have a limit value, after which the session is forced to break to recalculate the tariff or simply to avoid a channel freeze.

If your call is terminated in exactly 240 minutes (4 hours), it is a hardware restriction of the operator's network equipment that cannot be changed by the phone settings. Neither the flashing nor the engineering codes will help here. The only technical solution in this case is to organize automatic callback or use conferencing services that support the break and restore the connection.

However, if the break occurs earlier (for example, after 1 hour or 30 minutes), this may be due to the timeout settings of the inactivity in the radio module. CDS Information -> Ril Configuration) can be found in the Call Duration Limit (if available for editing on your model) and can be set to 3600 seconds by default. Changing this value by 0 or more (e.g. 14400 for 4 hours) may solve the problem, but requires root access rights or specific access rights. ADB-team.

⚠️ Note: Editing the radio module configuration files (persist section) without a backup can lead to loss IMEI You can only act if you understand the risks.

Use of third-party applications and alternative calls

If Xiaomi’s standard Phone app doesn’t work properly or has hidden region restrictions, the best way to do that is to install an alternative calling app. Google Phone (Google Dialer) is the Android standard and often lacks the regional restrictions present in Xiaomi’s stock firmware.

There are also dedicated call management applications, such as Truecaller or Call Recorder (with extension function), that can intercept call management. Some of them are able to automatically initiate a call-on-break, creating the illusion of a continuous conversation for interlocutors. To install Google Phone on global versions of MIUI, you may need to obtain superuser rights or use installation methods through ADB, since the system can block the replacement of the system component.

The installation process via ADB (requires USB debugging enabled):

adb install com.google.android.dialer.apk

Once installed, you need to go to the app settings, find the Phone, and install the Google app as the “Default App” for making calls, often completely solving timer and connection instability problems.

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If you need to talk for more than 4 hours, you should switch to WhatsApp, Telegram or Signal – they use an Internet channel and do not have strict operator time limits.

Hardware causes and the effect of SIM-card

You cannot discount your physical condition. SIM-maps and antenna modules. SIM-cards, especially hand-cut or issued more 5-7 In the past, it may not work properly on modern networks. 4G/5G Heating the card chip causes network out-of-synchronization and disconnection. SIM-map USIM and 4G — It is free and often solves the problem.

Also worth paying attention to the case. Metallized or too thick cases can cause the antenna module to overheat during prolonged conversation, especially if you use the phone as a navigator or GPS is turned on. The thermal protection of the smartphone can force the radio module to turn off for cooling, which is perceived as a call break. Remove the case and check if the problem persists.

In rare cases, the problem lies in the oxidation of contacts. SIM-Take out the tray, wipe the contacts. SIM-The card and the tray itself with an alcohol napkin or a stripe, even a microscopic film of oxide can create resistance sufficient to malfunction during prolonged operation.

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Integrated approach: most often the problem is solved by replacement SIM-map or region change in phone settings, not complex technical manipulations.