Modern smartphones brand Xiaomi has long ceased to be just devices for calls, turning into powerful multimedia centers, but the basic functionality of communication remains a priority. DSDS, which can be found in specifications or engineering menus, means Dual technology SIM Dual Standby is a mode that allows the device to hold two active devices simultaneously. SIM-cards on the network without requiring the user to switch manually between them.
Many owners of Redmi and Poco devices are wondering how to activate this feature and whether it is really needed in their use scenario. Unlike the old standards, when one card worked and the second was not available before the switch, DSDS ensures that both numbers are always ready for calls and SMS. Understanding the principles of this technology will help you to set up communication on your gadget as efficiently as possible.
In this article, we will discuss in detail the technical details of the communication module, how to activate the mode through the standard menu and hidden engineering codes. The key difference between DSDS and a full-fledged DSDA is the use of a single radio frequency module that quickly switches between SIM cards, creating the illusion of their simultaneous operation, you will learn how to avoid typical errors when setting up and why in some cases a second SIM card can go into “Offline” mode.
Dual SIM Dual Standby Technology: The Principle of Operation
Dual Technology SIM Dual Standby is based on the ability of the processor and modem to quickly switch the radio between two subscriber cards. SIM-The cards are registered in the operator's network and ready to accept an incoming call, but when one card is actively spoken to, the second card temporarily goes into standby mode or becomes unavailable if VoLTE technology or operator-specific settings are not supported.
In Xiaomi devices, DSDS implementation often depends on the installed firmware version (MIUI or HyperOS) and the regional affiliation of the device. Global firmware versions may have restrictions related to frequency licensing or software locks, while Chinese versions often provide more flexible settings for working with two SIM cards. It is important to understand that a physical tray can support two cards, but software mode of their operation may be limited.
There is a misconception that DSDS allows data to be transmitted simultaneously through both SIM cards, summing the speed. In fact, mobile Internet in this mode only works through one selected card, while the second is exclusively occupied by voice communication and SMS. Switching the data flow between cards occurs automatically when you change priority or manually by the user through settings.
⚠️ Note: When you actively use navigation or heavy online games via the mobile Internet of one SIM card, the second card may temporarily lose network during an incoming or outgoing call on the first. DSDS, non-malfunctional.
Preparation of the smartphone and compatibility check
Before you start activating DSDS, you need to make sure that your Xiaomi device technically supports two SIM cards in standby mode. Most modern models, from the budget Redmi Note to the flagships of the Mi series and Xiaomi Numbered dedicated series, have a hybrid or tray for two Nano-SIM. Checking begins with a visual inspection of the tray and study the specifications of a particular model on the official website.
The second important step is to update the software. Communications operators are constantly changing network settings, and older versions of firmware may not properly process the second SIM card registration signals. Go to Settings → About Phone → MIUI version and check for updates. Having current security patches often solves problems with unstable signal.
It is also worth checking the status. SIM-- You have a card with your carrier, an outdated Mini-SIM card or SIM, Hand-cutting scissors may not provide reliable contact or support the necessary communication protocols. Replacing a card with a new Nano-SIM in the operator's cabin is a simple action that eliminates physical contact problems.
☑️ Checking readiness for setup DSDS
Standard activation via the settings menu
The safest and most recommended way to enable DSDS on Xiaomi smartphones is to use the standard operating system interface. Manufacturers have provided a user-friendly interface for managing SIM cards that hides complex technical details from the user. First, insert both SIM cards into the tray and wait for the system to fully load.
Go to the settings menu and find the SIM card and mobile network section, which shows both cards installed. If one of them is not active, click on its icon and switch to "On" and the system will automatically try to register the card on the operator's network, which can take from seconds to minutes.
Next, you need to set priorities. In the Default block, select which SIM card will be used for mobile Internet and which for voice calls. In DSDS mode, it is critical to set the settings "Other SIM card settings" correctly. Here you can turn on the "Always Ask" function for calls if you want to choose a card manually before each set, or set tough rules for different contacts.
| Setup parameter | Recommended value | Impact of DSDS work |
|---|---|---|
| Mobile Internet | SIM 1 (main) | Prioritizes the speed of data transfer |
| Voice calls | Always ask | Allows you to flexibly choose a map for outgoing |
| SMS default | SIM 1 | Map from which messages will be sent without selection |
| Access to data | Permitted. | Necessary for the work of messengers and applications |
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If after switching on the second SIM card, the sound in the speaker disappeared, check whether the sound switched to the Bluetooth headset or whether the Do Not Disturb mode for one of the cards is activated.
Use of the Engineering Menu for Advanced Customization
For advanced users who don't find the right options in the standard menu, there is a hidden engineering menu that allows you to manage modem parameters at a deeper level. Be careful: changing unknown parameters can lead to unstable network operation or complete disappearance of the signal. To enter the menu, open the Phone application and type the combination ##4636#.
In the menu that opens, select Phone 1 Information (for the first SIM card) or Phone 2 Information. Find "Configure preferred network type." Here you can force a mode, such as LTE Only or NR/LTE/GSM. For proper DSDS operation, it is recommended to choose modes that support 4G/LTE, since the old 2G/3G standards can conflict with the simultaneous operation of two cards.
In some versions of the firmware MIUI There is a separate menu to set preferences SIM-maps available through ##888## or similar, depending on the region. SIM If the switch is active, it forces both cards to be active, preventing them from falling asleep, which can increase battery consumption.
⚠️ Warning: Never change the settings in the "Radio Power" or "Band Mode" section unless you know exactly what frequencies your carrier and base stations in your area support.
What to do if the engineering menu is not opened?
Typical Network Problems and Conflicts
Even after setting up correctly, users may experience a situation where one of the SIM cards periodically loses the network or displays an “R” icon in the home region, often because the modem cannot support two 4G LTE channels at certain frequencies at the same time, in which case one of the cards is forced to switch to 2G/3G mode to provide voice communication.
The solution to this problem is a manual network. Go to the SIM card settings, select Network Type, and try to change priority. For example, if the main card is running in LTE and the second card is falling in 2G, try for the second card to explicitly specify "Preferred to 3G" or "Only 2G" if you only care about calls, this will unload the radio module and stabilize the connection.
Another common problem is that you can't make an outbound call while you're on the second line, which is a limitation of the DSDS architecture. The only effective solution is to activate VoLTE (Voice over LTE) from the operator, which allows voice to be transmitted as a data stream on a 4G network, freeing up channels for a second SIM card and allowing you to talk on one card and use the Internet or make calls to another simultaneously.
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The stability of two SIM cards depends on the support of VoLTE technology by your operator and the tariff plan. Without VoLTE, voice and data on different cards cannot be physically worked simultaneously.
The effect of DSDS mode on the autonomy of the device
Using two active SIM cards inevitably affects battery life. Dual Standby mode requires the radio to constantly poll two different base stations, even when the phone is lying on the table. This leads to increased background energy consumption, especially in areas of uncertain reception, where the phone is forced to constantly search for the network.
The intensity of the discharge also depends on the type of networks used. If both SIM cards are registered on 4G/5G networks, the battery consumption will be higher than when working in mixed mode (one 4G, one 2G). Users for whom autonomy is critical are advised in the settings of the second SIM card, used only for calls, to limit the network type to 3G or 2G, if the quality of communication allows this.
To minimize the impact on the battery, you can use the “Sleep Mode” feature for applications that actively use the second SIM card network, or set up automatic shutdown of mobile data at night. Xiaomi smartphones have built-in battery optimizers that can limit the background activity of the second SIM card, but this can lead to delays in receiving notifications.