How many? SIM-Maps in Xiaomi Mi 9: full analysis

Many users, choosing a new smartphone, ask about the functionality of the communication module. For the Xiaomi Mi 9 model, this aspect is especially important, since the device is positioned as a flagship, which means that the requirements for speed and stability of the connection are maximum. Owners often wonder how many sim cards in the Xiaomi Mi 9 can be used simultaneously to separate work and personal calls.

The company's engineers have provided support for two physical SIM-Nano-SIM cards are a classic solution for Chinese flagships of the period, which allows you to maintain a balance between the compactness of the case and functionality. However, as with many modern devices, there are some nuances with memory that you should know about in advance.

In this article, we will discuss in detail the design of the tray, the features of the two SIM cards in the Xiaomi Mi 9 and the possible limitations when using memory cards. You will learn how to properly install communication modules to avoid network identification problems or signal drops.

Tray design and types of supported cards

The connector for installing communication modules is located on the lower end of the case, next to the USB Type-C port. To remove the tray, you need to use a special key-clip, which comes with a package, or a thin needle. The design is made in the form of a retractable frame, which is the standard for moisture-proof and modern smartphones.

The tray in Xiaomi Mi 9 is a combined type, but not in the usual sense of "either-or." It is equipped with two full seats for Nano-SIM cards. This means that you can use two SIMs in Xiaomi Mi 9 at the same time without any adapters or tricks.

It is important to note that one of the slots is combined with a microSD card slot, which creates a dilemma for users who need to expand their internal storage, and if you insert a memory card, one of the SIM card slots will become unavailable for use.

⚠️ Note: The Xiaomi Mi 9 SIM card tray is asymmetrical in shape. Do not try to insert it by force unless it enters the first time - this can cause the mechanism to break or damage the contacts inside the case.

For clarity, consider the compatibility of formats:

• 📱 Nano-SIM – the main format, supported by two modules.
• 💾 microSD – supported up to 256 GB (officially), takes the place of the second SIM.
• 🚫 Micro-SIM/Standard-SIM – not supported, trimming or adapter required (not recommended).

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Use only the original key to extract the tray. Sharp objects such as scissors or pins can slip and damage the microphone or speaker located near the hole.

Dual SIM support and network modes

When two SIMs are installed in the smartphone, the Xiaomi Mi 9 goes into Dual SIM Dual Standby (DSDS) mode. This means that both cards are active and ready to receive calls or SMS, but there can only be one active voice channel. If during a call on the first line, a call to the second one is received, the subscriber will hear a signal “busy” or will be forwarded, depending on the operator’s settings.

One of the key features of the model is support for modern communication standards. Qualcomm Snapdragon 855 hardware platform allows both slots to work on 4G LTE networks. However, in practice, when one card is occupied with voice call in 4G mode, the second can switch to 3G or 2G if VoLTE is not enabled.

To work smoothly with two SIM cards in the Xiaomi Mi 9, you need to set your priorities in the device menu correctly. The MIUI system installed on your smartphone provides flexible tools for managing traffic and voice calls. You can assign one card to the Internet and the other card exclusively for calls, which helps save battery power.

Technical characteristics of communication modules:

• 🌐 4G LTE — Full Cat.16 support, frequency aggregation.
• 📞 VoLTE / VoWiFi – support depends on your operator and region.
• ⚡ Switching – Automatically Selecting the Best Network to Save Energy.

The problem with the memory card and SIM: choosing a priority

As mentioned, the slots in Xiaomi Mi 9 are not completely independent in terms of physical installation.The design of the tray is such that the microSD card and the second one are not completely independent. SIM-It's a common practice, but it requires the user to decide whether to add more memory or to have a second number?

If you decide to use a memory card, you will have to remove one of the SIM cards, in which case the phone will work in one SIM mode. For many users, 128 GB of internal memory (the basic version) may not be enough, especially given the high resolution photos and videos that the Mi 9 camera captures.

But there is an alternative: instead of a physical memory card, you can use cloud storage or transfer files over the network, and if you choose hybrid mode, make sure that the memory card is high-quality and has a high speed class (UHS-I or higher) so that you do not slow down the system.

Setting up two SIM-map MIUI

After the physical installation of the modules, you need to properly configure the software part. MIUI It allows you to flexibly manage two SIMs in Xiaomi Mi 9. → SIM-Maps and mobile networks to see the list of active connections.

Here you can assign a default card for different actions, for example, for outgoing calls, you can set "Always Ask" to choose which number to call from each time, and for mobile Internet, you better choose the card with the highest traffic packet to avoid unnecessary costs.

The "Call Receiving" feature deserves special attention, and in this menu you can configure whether the second SIM will receive calls when the first SIM is busy talking, and if this option is disabled, the second subscriber will hear the beeps or get to the answering machine.

Also available in this section is the setting of operator names, so if you use virtual operators or MVNOs, the names may not appear correctly, and you can manually rename them to "Worker" and "Personal" for example, so as not to get confused in the status bar.

Solving Network Definition Problems

Sometimes users are faced with a situation where the Xiaomi Mi 9 does not see the SIM card or loses the network.This can be due to a software failure, contamination of contacts or problems with the communication module itself.

If the reboot didn't work, try removing the tray and wipe the SIM card contacts with a soft dry cloth. Fat contamination or oxidation can prevent normal electrical contact. Also make sure the card is mounted on the correct side, according to the tray circuit.

⚠️ Warning: Do not use alcohol or other aggressive liquids to clean your contacts SIM-This can damage the plastic base of the card or cause corrosion of metal sites.

If one of the SIM cards in the Xiaomi Mi 9 doesn't work, try swapping them. If the problem goes to another slot, it's the card itself or the operator's settings. If the same slot stops working, the phone's hardware module may be faulty.

Additional steps for diagnosis:

• 🔄 Resetting network settings – return parameters APN Network preferences for factory.
• 📡 Manual Search – Try to select the operator manually from the network menu.
• 🛠️ Engineering menu – Entering code ##4636## allows you to check the status of the radio module.

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If the SIM card is not detected after all the manipulations, check its operation in another phone. This will eliminate the malfunction of the Xiaomi Mi 9 communication module itself.

The Impact of Two SIMs on Autonomy and Performance

Using two active SIM cards in Xiaomi Mi 9 The smartphone has to communicate with two base stations at the same time, which increases the power consumption of the radio module. 15-20%.

The Snapdragon 855 processor is quite efficient, but constantly searching for a network or switching between 3G and 4G on two channels creates an additional load. If you are in a zone of confident 4G reception, the difference will be less noticeable than on a trip when the phone constantly switches between towers.

To optimize the work, you can turn off the second SIM card software if you don’t need it at the moment, this is done through the notification curtain or in the settings, and it is also recommended to turn off 5G (if available in your region through the engineering menu), as this mode consumes more power.

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For maximum charge savings when using two SIM cards, set the 4G network type for both cards if your carrier supports VoLTE. This will prevent constant jumps between 3G and 4G.

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