Modern smartphones from the company Samsung have long become a standard in the segment of devices with support for two physical SIM cards or one physical and one virtual (eSIM). For many users, the ability to separate work and personal contacts and optimize communication costs is a critical feature. However, the shell interface One UI may not be obvious to beginners, especially when it comes to quickly switching between lines while making a call.
The main difficulty lies not in the ability to install a second card, but in managing priorities. The system Android on devices Galaxy offers flexible settings that allow you to set a fixed SIM card for calls or request a choice before each dial. Understanding these mechanisms will save you from unnecessary expenses and missed calls at the most inopportune moment.
In this material we will analyze in detail the algorithms for setting up voice calls, consider the nuances of working with VoLTE i Wi-Fi Calling on different lines, and also provide solutions for common problems when the second SIM card suddenly stops connecting to network or make calls.
Initial setup and activation of SIM cards
Before making calls, you must make sure that both lines are correctly identified by the system. Insert the cards into the tray, following the shape of the cutout, and wait until the network icons appear at the top of the screen. Usually these are two icons with signal strength indicators, next to which the names of operators or line numbers (SIM 1, SIM 2) may be displayed.
Go to the main settings menu of your device. Find the partition, which, depending on the firmware version, may be called Connections or immediately SIM card manager. This is where the distribution of roles between cards occurs. If one of the cards is not active, move the corresponding slider to the position Enabled.
Pay attention to item Mobile data. Users often mistakenly believe that choosing a SIM card for the Internet automatically determines the line for calls, but these are different settings. You can use fast mobile data from one operator, and make voice calls through another, which is especially important when roaming or specific tariffs.
⚠️ Attention: If you use cards of different form factors (for example, an adapter for an old Mini-SIM), make sure that the contacts are pressed securely. Poor contact can lead to periodic network failures, when the phone sees the second SIM card, but does not allow you to make a call.
☑️ Checking readiness for calls
Selecting a SIM card for an outgoing call
There are several scenarios for making calls, and Samsung allows you to customize the behavior of the system for each of them. The easiest way is to select a line immediately when dialing a number. Open the application Phone and enter the subscriber number. In front of the call button you will see a SIM card icon.
Click on this icon to expand the list of available lines. The system will remember your last choice for a specific contact or number, making repeat calls easier. If you want the phone to always ask which card to call from, you need to change the global settings in the menu SIM card manager.
In this menu, find the item Voice calls. There are three options available here: “Always ask”, “SIM 1” or “SIM 2”. Selecting the “Always Ask” mode is the safest from a financial point of view, as it eliminates the possibility of accidentally calling from an expensive line instead of a cheap one.
- 📞 Always ask: the phone will display a pop-up window with a choice before each number dialed.
- 🔵 Prefer SIM 1: all calls go through the first card unless you manually select the second.
- 🟢 Prefer SIM 2: similar, but priority is given to the second card.
Quickly switch lines through the notification panel
For those who value speed, there is a more efficient method of managing lines without going into a deep settings menu. The notification shade on smartphones Galaxy contains useful widgets for managing communications. Swipe down from the top of the screen twice to expand the full Quick Settings panel.
Find the tile that says Calls or the handset icon. Clicking on it cyclically switches the main SIM card for voice communication. This is convenient when you are in an area of poor reception of one network and want to temporarily transfer all calls to another operator.
You can also set up the “SIM Card Manager” widget on the home screen. A long press on an empty area of the desktop will allow you to add a widget that displays the status of both cards and allows you to change their purpose in one click. This eliminates the need to search for the desired item in the system every time.
⚠️ Attention: The quick settings interface may differ depending on the version One UI. If you don't find the Calls tile, click on the three dots in the upper right corner of the panel and select Edit Buttons to add it manually.
Add the SIM Card Manager widget to your home screen to instantly switch lines without going into settings. This saves time in critical situations.
Features of working with contacts and call history
Managing the contact list on a dual-SIM device has its own nuances. When saving a new number, the system will prompt you to select a storage location. It is recommended to save contacts in your account Google or Samsung Cloud, and not on the SIM card itself, to avoid data loss when changing operators or damaging the chip.
In the call log (Last), each entry is marked with a color indicator or signature (1 or 2), indicating through which line the conversation took place. This helps you quickly understand which number you called a specific person from, and, if necessary, call back from the same line so that the subscriber sees the usual number.
For frequently used numbers, you can assign a link to a specific SIM card. Go to the contact card, click on the call button next to the number and select the desired line. In some firmware versions, you can set the option “Always use this SIM for this contact” in the number details.
| Option | SIM 1 (Primary) | SIM 2 (Additional) |
|---|---|---|
| Default status | Often used for personal calls | Often used for work tasks |
| Indicator in the log | Blue or green marker | Green or gray marker |
| 5G support | Full support (on new models) | Limited or works in 4G mode |
| Data roaming | Easy to configure separately | Requires manual activation in the menu |
Problems with outgoing calls and their solution
Sometimes users are faced with a situation where a call from the second SIM card simply does not go through, resets or the phone says “Not registered on the network.” First of all, check whether the mode Only 4G/LTE is activated in the hidden menu, if in your region the second operator does not have coverage of this standard in this location.
Go to Settings → Connections → Mobile networks → Network mode. Make sure that the automatic mode is selected, for example 5G/4G/3G/2G (auto-connect). Forced switching to the old communication standard may be necessary only in areas of extremely weak signal, but for the second SIM card this often causes calls to be blocked.
If the problem persists, try clearing the application cache Phone i SIM card management. Go to Settings → Applications, find the desired application, select Storage and press Clear cache. This will not delete your contacts, but will clear temporary configuration errors.
Hidden codes for checking network status
You can use engineering codes for diagnostics. Enter *#0011# to view detailed information about connecting to cell towers. This will help you understand whether the phone sees the second SIM card at all.
VoLTE and Wi-Fi Calling technologies on two SIM cards
Modern communication standards, such as VoLTE (Voice over LTE) and Wi-Fi Calling, significantly improve sound quality and speed connections. On smartphones Samsung these features can be enabled independently for each SIM card, which gives greater flexibility.
VoLTE allows you to make calls over a 4G network without switching to 3G or 2G during a call. This is especially important for the second SIM card if it is used as the main one for data: without VoLTE, the Internet may be temporarily disconnected during an incoming or outgoing call. Activation is carried out in the menu Mobile networks for each card separately.
The function Wi-Fi Calling is irreplaceable in rooms with a poor cellular network signal, but stable Wi-Fi. If you are in a basement office or a thick-walled building, enabling this option for a second SIM card will allow you to receive work calls without losing quality. Make sure your operator supports this technology.
⚠️ Attention: Terms of VoLTE and Wi-Fi Calling services depend on your operator's tariff plan. Even if the phone supports the function, it may not work without connecting the corresponding service from the communication provider.
For stable Internet during a call on the second SIM card, be sure to enable VoLTE, otherwise the data transfer speed will drop to a minimum (2G/EDGE).
Frequently asked questions (FAQ)
Why the second The SIM card does not see the network, although the first one works?
This may be due to the network mode settings. Try manually selecting the operator in the menu Settings → Connections → Mobile networks → Telecom operators for the second card. Also check if the card is blocked due to lack of payments.
Is it possible to assign different ringtones for calls from different SIM cards?
Yes, in the standard Samsung Phone application you can set a unique ringtone for each SIM card. Go to the call settings and find the item “Ringtone SIM 1” and “Ringtone SIM 2”.
What happens if you remove one SIM card while talking through another?
The conversation will not be interrupted, since the communication modules work independently. However, if you used the forwarding function or a conference call involving both numbers, the connection may be lost.
How to find the IMEI of the second SIM card?
Dial the code *#06# on the dial pad. Information on both cards will be displayed on the screen. Typically, the IMEI for slot 2 is listed second in the list or marked with the corresponding index.