Owners of Xiaomi, Redmi and Poco smartphones often face the need to transfer contacts or check the free space on the SIM card when changing devices, this is especially true when switching from button phones, where the storage of numbers was carried out exclusively on the operator’s chip. Modern smartphones offer advanced features, but basic contact management functions remain important for many users.
It is necessary to immediately clarify the technical nuance: the amount of memory itself SIM-The card is extremely limited and usually ranges from 128 to 512 Kb. This is enough only for storing phone numbers and names, but not for photos, applications or messages. When users are looking for a way to check memory, they often have in mind either the number of free contact slots or the state of the phone's storage associated with synchronization.
In this article, we will discuss all available methods for diagnosing and managing data on a SIM card through the MIUI and HyperOS shell. You will learn how to correctly export records, avoid data loss and understand the real capabilities of your equipment.
Technical limitations and types of SIM memory
Before we get to practical action, we need to understand the storage architecture, because a SIM card is not a flash drive as we know it, but a dedicated subscriber identity module, and its physical memory is divided into several sectors that are regulated by the carrier and GSM/3G/4G standards.
The main volume occupies the storage area IMSI-It's code, encryption keys, and network settings, and for user data like the phone book, there's only a small snippet. That is why when you try to copy contacts from your phone to your SIM card, you can see a message about a lack of space, even if several gigabytes are free on the device itself.
⚠️ Note: Do not attempt to use third-party programs for “cleaning” or formatting SIM-This can lead to irreversible chip lockdown and loss of access to the operator's network.
Modern standards allow you to store on a chip numbers up to 20 characters and names up to 14 characters long (sometimes less, depending on the encoding). If the name of the contact is longer, it will be cropped when saved.
- 📱 Standard contact capacity: 150 to 250 records.
- 🔒 Security sector: contains PIN and PUK codes not available to the user.
- 📉 Lack of multimedia support: photos and ringtones are not saved SIM.
Checking the occupancy through the standard contact menu
The easiest and safest way to check how much space is occupied on your Xiaomi SIM card is to use the built-in Contacts app. The MIUI shell interface allows you to quickly assess the situation without installing additional software.
In the upper right corner of the screen, find a three-dot icon or a gear that represents the settings menu. Click on it and select "Import and Export Contacts" or "Contact Management" and in this section, the system displays all available storage: internal memory, Google account and installed SIM-map.
When choosing a particular SIM card (e.g. SIM 1), the phone can show a list of saved numbers. Although there is often no accurate 5 seats out of 250 indicator in modern versions of Android, you can visually assess the occupancy or try to create a new contact by choosing to save to SIM. If the place is over, the system will issue a corresponding warning.
For more detailed analysis, you can use the copy function, try to copy all contacts from your phone to your SIM card, and the process will start, and the system will automatically stop when the chip memory is exhausted, reporting the total number of saved records, which is an effective method of testing capacity.
Using the Engineering Menu for Diagnostics
For more advanced users who want to access technical information about the status of the communication module, there is an engineering menu. This is a hidden partition of the Android system that provides signal, battery and status data. SIM-On Xiaomi smartphones, it is entered through a special code.
Open the Phone app and type in the combination ##4636##. If the code works, the Test menu will open. Select Phone Information. This shows the technical settings, but direct information about SIM bytes is not usually provided here, as Android abstracts this access layer.
##4636##However, this menu can check the status of the registration on the network and the type of card. If the SIM card is physically damaged or has file system errors, the phone may not see it at all or constantly request it. PIN-In this case, the problem is not the lack of space, but the integrity of the chip data.
⚠️ Warning: Be extremely careful in the engineering menu. Changing the settings in the "Install preferred network type" section or resetting a radio module without understanding the consequences may temporarily deprive the device of communication.
If standard code doesn’t work (newer versions of MIUI often block it), you can try using applications to view system information, such as AIDA64 or Device Info HW. They can read the data about the manufacturer of the SIM and its volume through the standard system APIs, but the detail will be limited by the capabilities of Android.
Exports and Imports: How to Make Place
If the check showed that the SIM card memory is full, the only solution is to clean or transfer the data.The optimal scenario for Xiaomi owners is to transfer all contacts to the Google cloud service. This will not only free up space on the chip, but also ensure the safety of data when the phone is lost.
Go to the contact settings, select Import/Export and click Export to Google Account or Export to Memory (.vcf). Once you have created a copy, you can delete the contacts from the SIM card. To do this, select a SIM card from the contact management menu, tick all numbers and click Delete.
☑️ Safe transfer algorithm
Once cleaned, you can copy the most important numbers from your phone to your SIM card again, if it's used as a backup medium in another, push-button phone. SIM-the card is up to date and avoid errors when writing new numbers.
- 💾 VCF: A universal standard for backup.
- ☁️ Synchronization: Automatic updates when the Internet is available.
- 🗑️ Cleanup: Complete deletion of data frees up all available cells.
Comparison of storage: SIM, Phone and Cloud
Understanding the differences between memory types will help you organize your phone book properly, and here is a table that shows the key differences that affect where you store your data on Redmi and Poco devices.
| Characteristics | SIM-map | Phone Memory / Google | Internal memory (file) |
|---|---|---|---|
| Capacity | Limited (150-250 contacts) | Almost unlimited. | Depends on the space available. |
| Length of name | Up to 14 characters (often cropped) | No restrictions. | No restrictions. |
| Supplementary fields | Only number and name. | Email, address, photos, notes | Full support for vCard |
| Security | Protection PIN-code | Protecting your Google account | Depends on the screen lock. |
As can be seen from the table, the use of SIM-as the primary storage facility in 2026-2026 It's an archaic method, and modern smartphones are cloud-based, but the ability to read and write to a SIM card remains an important interoperability feature.
Why are contact names cut?
Solution: Errors and Display Problems
Xiaomi users sometimes face a situation where the phone sees the SIM card but does not display contacts, or vice versa, shows duplicates. Often this is not due to memory overflow, but to display settings. In the Contacts app, click on three dots and select Display Settings.
Make sure you check the box against the SIM card you want, also check if it's group filtering enabled. If contacts are missing after the firmware update, try clearing the Contacts cache through the Apps menu -> All Apps -> Contacts -> Clear -> Cache.
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If the contacts are displayed in squares or characters, then the encoding of the names on the SIM-The map doesn't match the system card. Copy them on your phone, rename them and re-write them.
In rare cases, you may need to reset your network settings completely. → SIM-Maps and mobile networks and try to switch network mode from 5G/4G on 3G/2G And that will restart the communication module and update the reading from the chip.
⚠️ Note: If the phone is writing «SIM-Card blocked or Enter PUK», Do not enter random codes, three wrong inputs. PUK-code will forever destroy the SIM card, and you will have to contact the operator for a replacement.