Many owners of Xiaomi smartphones are faced with a situation when during a conversation an incoming call is simply reset, and the subscriber hears the signal “busy”. This is not a network failure or a device breakdown, but only a disabled option that may be inactive in some regions or when using certain regions by default. SIM-The function of waiting for a call is critical for those who are used to keeping abreast of business and personal contacts, allowing you not to miss an important conversation even during an active conversation.
In the MIUI and HyperOS ecosystem, this option is not always intuitively managed. The interface of Google’s standard Phone application, which is installed on most modern Xiaomi models, has its own navigation features that differ from the usual Android menus of previous years. In addition, telecom operators often use their own network settings, which can conflict with the software parameters of the smartphone, creating the illusion of a malfunction.
In this article, we will take a look at all the ways you can activate a service, from standard menu settings to secret engineering codes. You will learn why a slider in settings can be inactive, how to fix it, and what nuances exist on different versions of firmware. Understanding these mechanisms will allow you to fully control your phone traffic.
⚠️ Attention: Call Waiting is a network service, which means that it depends not only on your smartphone, but also on carrier support. If the function does not work after all the settings, contact your data plan support team.
Standard activation through the phone application
The easiest and safest way to enable the option is to use the built-in call settings menu. On Xiaomi, Redmi and Poco smartphones with global firmware, the Google Phone app answers the dial and call management app to get to the desired menu, you need to open the app and click on three dots in the upper right corner of the screen.
In the context menu that opens, select Settings, and then the system will suggest a list of options, among which we are interested in the Accounts section or immediately the option “Additional settings” (depending on the version of the interface), which is where the switch for network functions hides, find the “Waiting for a call” line and activate the slider.
Once the slider is turned on, the system will send a request to the operator's network, and for a few seconds the message "Update is coming..." or "Request completed." If you see an error message or the slider immediately returns to the "off" position, then the command did not pass through the network, in which case you need to check the account balance or the availability of the service in the tariff.
☑️ Verification of activation of the function
It is worth noting that on two-symbol devices, the settings can be displayed separately for each SIM-Make sure you activate the feature for the card you plan to talk to. If the slider is gray and doesn't click, try switching to another SIM tab at the top of the settings screen.
Use of the USSD-service-management codes
If the GUI doesn’t respond or gives an error, the most reliable method is to direct the network through the network. USSD-This method works on any phone, regardless of the version of Android or shell. MIUI, since the request is processed directly by the operator’s equipment, bypassing the software settings of the smartphone.
To manage the call waiting service, the universal code 43# is used. To activate the function, dial this number in the Phone app and press the call button. In a few seconds, you will receive a pop-up notification or SMS from the operator confirming the service's activation. To disable the function, the code #43# is used, and to check the current status - #43#.
For example, some providers use specific combinations to activate via the self-service menu. However, *43# is an international standard that works on most GSM networks. After entering the code, be sure to wait for a confirmation message before completing a call.
⚠️ Attention: Do not enter USSD-When a signal is actively spoken or poorly signaled, interruption of the data transmission may result in the command not being executed and the status of the service remaining unchanged, causing confusion in the future actions.
What if the code doesn't work?
Configure through the engineering menu and hidden options
For advanced users who have not found standard settings or have encountered firmware bugs, there is access to a hidden engineering menu that allows you to manage deep network parameters, including forced activation of service functions. Be careful: changing unknown parameters can lead to unstable operation of the communication module.
To enter the test menu, dial ##4636## in the dialer. Immediately after entering the last star, the hidden Testing menu will open. Select Phone Information. In the list that opens, find the section related to call settings or networking, and the call waiting checkbox or similar may be present.
If there is no explicit switch in the Testing menu, you can try resetting the network settings to factory settings, which often helps if a software failure blocks the feature from turning on. To do this, find the Reset radio module button on the same menu or use the command ##72786## (does not work on all models). After rebooting the phone, try activating the call wait in the standard way.
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Before entering the engineering menu, write down or take a picture of the current values of all parameters, which will allow you to return the settings back in case the phone stops catching the network after the changes or starts having problems with calls.
Specifics of work on different versions of MIUI and HyperOS
The MIUI shell is known for its variability: On smartphones with the Chinese firmware (CN), the Phone app has been replaced by Xiaomi’s own development, which has a different interface from the global version. In Chinese firmware, call settings are located in the Security app or in the general system settings in the Applications section → System applications → Phone.
With the release of HyperOS, Xiaomi began to unify the interface, but the logic of the layout of menu items remained similar. The main difference is the speed of the interface response and the way the network settings are caching. On new versions of the OS, activation of the function may take longer because of the enhanced security protocols that check the access rights of the Phone application to the communication module.
It’s also worth considering the different ways the function works on different processors. On Snapdragon and MediaTek chips, modem drivers work differently, which sometimes affects the stability of the second call display. If one Xiaomi is working perfectly and the other of the same model is failing, the problem may lie in a particular software build.
| System version | Location of settings | Features of work |
|---|---|---|
| MIUI Global | Phone → Settings → Accounts | Google’s standard interface, high compatibility |
| MIUI China | Security / Settings → Annexes | Chinese app calls, possible menu differences |
| HyperOS | Phone. → Settings → Additionally. | Accelerated processing of requests, possible bugs in early versions |
| Android One | Phone → Settings → Challenges | Pure Android, settings are in the system menu |
Problem Solving: Why Call Waiting Is Not Enabled
When a slider in settings is not activated or immediately disabled, it is a common problem. Most often the reason lies in the conflict between the settings of the smartphone and the operator profile. The operator can force to disable the service on its side if it is not included in your plan or if there are not enough funds in the account to activate it.
Another common reason is the use of VoLTE (Voice over). LTE). Voice transmission technology through 4G The network sometimes conflicts with standard call waiting protocols. If you have VoLTE enabled, try temporarily disabling it in the settings. SIM-maps (Settings) → SIM-maps and mobile networks → Use VoLTE) and check the function again.
Also, the issue may be an outdated version of the Phone app or Google Play Services. Make sure all system components are updated through the Google Play Store. In some cases, cleaning the Phone app cache helps: go to Settings → Apps → All Apps → Phone → Clear the cache.
⚠️ Attention: Clearing the data (not just cache) of the Phone application will delete the call history. Be careful when choosing a menu item so as not to lose important information about the calls made.
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If the call wait slider is inactive (grey), the problem is 90% on the carrier’s side or profile. SIM-cards, not in the smartphone itself.