Many Xiaomi smartphone users face an unexpected problem: the Add Call or Make a Second Call button simply doesn’t work or is not in the interface during a conversation, which is puzzling, because flagship models have powerful hardware and must cope with any communication tasks without failure. However, the reason most often lies not in hardware constraints, but in software settings or locks on the part of your mobile operator.
The parallel call (or call wait) feature allows you to receive incoming calls without interrupting an ongoing conversation, or make new calls by putting the interlocutor on hold. In the MIUI ecosystem and the new HyperOS, managing these parameters can be hidden in different menu sections or depend on regional firmware. Understanding how this option works will help you avoid missing important calls and effectively manage multiple communication lines.
In this article, we will take a look at all the possible ways to activate the service, from the standard phone settings to the use of engineering codes.You will learn why the feature may not be available on your particular model and what to do if standard methods do not help you regain control of calls.
What is a parallel call and how does it work?
Call Waiting, also known as Call Waiting, is a standard for GSM and 3G/4G networks. It lets the operator's network know that your number is busy, but you're ready to take a second call. When someone calls you while you're talking, you hear a distinctive beep, and a notification of an incoming connection appears on the screen. Without activating this feature, the second subscriber immediately hears a "busy" signal.
In Xiaomi smartphones, not only the firmware but also the built-in Phone app is responsible for implementing this function. Depending on the version of MIUI, the interface may differ: in global versions, the standard Google Dialer is often used, and in Chinese or Russian firmware, the branded MIUI Dialer. It is the type of “caller” that determines the location of the control switches.
⚠️ Note: The parallel call service may be paid for by some operators or tariff plans. Before activating, make sure that your account has funds and the service is not blocked by default.
It's important to understand the difference between waiting for a call and conferencing. One allows you to switch between people, and the other allows you to combine them into one conversation. Both modes require an active call waiting service on the network side. If the network does not support this option for your number, no settings in the phone will make it work.
Activation through the standard settings menu
The easiest and safest way to enable the feature is to use the smartphone’s built-in interface.The path to settings can vary a little, but the logic remains the same across Xiaomi, Redmi and POCO devices. You don’t need third-party apps or root rights.
Open the Phone app (green handset) and find the menu button. Depending on the version of the shell, it can be either three dots in the corner of the screen or a gear "Settings." Going to the menu, look for the section associated with accounts or SIM-map.
The algorithm of actions is as follows:
- 📱 Find the "Settings" item SIM-"Card" or "Additional" (may be called "More»).
- 📞 Select “Parallel Call” or “Waiting for Call».
- ✅ Move the switch to the active position for the desired SIM-map.
- ⏳ Wait for confirmation from the network (usually a pop-up notification “Service activated” appears»).
If the switch is active but the function is not working, try turning it off and on again. Sometimes it takes a few seconds to synchronize the status with the operator's base station. In some cases, the system may request a confirmation code, which will come in the form of an SMS or pop-up.
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If the switch in the settings menu is gray (inactive), then the lock is at the operator or firmware level. USSD-code.
Use of the USSD-service-management codes
When the graphical interface does not work, help comes. USSD-This is a universal method that works even on push-button phones, since the command is processed directly by the operator's network, bypassing the complex Android settings. GSM.
Enter the following combinations in the dialing field as a normal phone number and press the call button:
- 🔹 *43# – activation of call waiting service.
- 🔹 #43# – Checking the current status of the service.
- 🔹 *43# (re-set) or #43# followed by menu selection – often used to disable.
After you enter the *43# command, you should see a message on the screen: “Service is activated” or “Call waiting enabled.” If you see a connection error message or “Code is not working”, this may mean that your operator is using non-standard codes or the service is blocked on the tariff.
*43#For subscribers of large Russian operators, specific combinations often work, for example, for Beeline it can be *110*101#, and for MTS it can be *111*129#. The exact codes are best specified on the official website of your operator, as they can change.
Configure through the engineering menu and access codes
In more complex cases, when standard methods fail, you can use the Android engineering menu, which is a hidden part of the system, designed for testing equipment. Be careful: changing unknown parameters can lead to unstable operation of the communication module.
To enter the engineering menu on Xiaomi, code ##4636## is often used. From the menu that opens, select Phone Information. Scroll down to Call Settings. There may be an item called Enable Call Waiting.
However, current versions of MIUI 12/13/14 and HyperOS often shut down these settings, and if you don't see the right options, you can try resetting your network settings to factory settings, which won't delete your personal data (photos, contacts), but will return the modem settings to their original state.
| Action. | Menu/Code | The result |
|---|---|---|
| Activation (GSM) | *43# | Network-side service inclusion |
| Status check | #43# | Displaying the current state |
| Engineering menu | ##4636## | Access to modem tests |
| Resetting the network | Settings → SIM-map | Online re-registration |
If you accidentally changed the extra settings in the engineering menu, a simple reboot may not be enough, in which case a complete reset of the network settings through the recovery menu or reset to the factory settings of the entire device will help.
Dual SIM Problems and Network Choice
Owners of two-sim Xiaomi often face a situation where a parallel call works only on one. SIM-It's connected to the architecture of the Dual modem. SIM Dual Standby (DSDS). Only one card is active in this mode, but both are ready to receive calls.
The problem may arise when switching between networks 4G and 2G/3G. If during the conversation 4G (VoLTE is not supported by the operator; the phone switches to the 3G For a second call, there may be delays or resets. SIM-data transfer enabled or at least one of them is stable.
⚠️ Note: Some Redmi models and POCO With budget modems, the simultaneous operation of two active voice channels may be technically limited, in which case the second call will only arrive after the first one is completed.
Also, check the settings for "Preferred network type" if "Only" is selected. 4G», The operator does not support VoLTE (Voice over) LTE) In your area, the call waiting function may not be activated «4G/3G/2G (auto)” in the settings SIM-map.
☑️ Diagnostics of Dual SIM
Specificity of operators and regional restrictions
Remember that Xiaomi sells devices all over the world, and the firmware adapts to local operators. The global version (Global) may differ from the Chinese (CN) or Indian (India), sometimes in the “clean” global firmware codes are missing specific to CIS countries.
If you've been reflashing your phone or bought a device that came from China, you may have firmware without Russian localization of the call settings menu. USSD-*43# is the only reliable method.
In addition, some virtual operators or Internet-only tariffs can programmatically block second-tier voice functions. Check your plan in the operator's personal account.