The modern rhythm of life requires smartphone users to be constantly available, but the standard call logic often becomes an obstacle: if you are talking, the second subscriber hears short busy beeps. The parallel call function (or call waiting) solves this problem by allowing you to receive incoming calls during an ongoing conversation without resetting the connection. This is a critical option for business communication, when missing a call can cost a contract or an important agreement.
In the operating system Android control of this function is implemented through the standard “Phone” application or system network settings, but the menu location may differ significantly depending on the OS version and the manufacturer’s shell. Understanding the operation principles GSM codes and settings of the SIM card will help you quickly activate the service even in the event of software interface failures. We will consider all available methods of activation, from the graphical interface to manually entering commands.
It is worth noting that the very possibility of holding a line depends not only on your smartphone, but also on the tariff plan of the telecom operator. Most modern plans support this feature by default, but some enterprise or legacy plans may have it disabled on the provider's side. If the phone settings do not help, the problem may lie in network restrictions.
The principle of operation of the call waiting service
Technically, the process of organizing a second call during a conversation is regulated by cellular protocols and controlled through special signals transmitted between the phone and the base station. When activated parallel callthe network does not block the incoming signal, but redirects it to your device in the form of a special tone. The user hears a characteristic intermittent sound, which notifies that someone is trying to call.
At this moment, a notification appears on the smartphone screen with the number of the second subscriber or his name from the contact book. The system offers several scenarios for the development of events: end the current conversation and switch to a new one, put the first interlocutor on hold and answer the second, or organize a conference call. All these actions are controlled by software Android in conjunction with the communication module.
⚠️ Attention: If you are in an area of unstable signal reception or are using the VoLTE (Voice over LTE) mode, the mechanism for switching between calls may work with a delay due to the characteristics of data transmission in 4G/5G networks.
It is important to understand the difference between call waiting and call forwarding. In the first case, you personally decide whether to accept the call while you are in a conversation. In the second case, the call is automatically redirected to another number or voicemail if the line is busy. Setting call waiting requires explicit confirmation from the user or activation via a USSD request.
To check the status of the service, you can use a short USSD request *#43#, which works on most GSM networks regardless of the phone model.
Activation via standard “Phone” application
The easiest and most intuitive way to enable the function is to use the settings of the built-in call application. In “pure” Android and shells from Google Pixel the path to the settings is usually unified, while manufacturers like Samsung or Xiaomi can change the menu structure. First, open the application Phonewhich usually has a green handset icon on the main screen.
Click on the three vertical dots in the upper right corner of the screen to open the context menu and select Settings. In the list that opens, you need to find the section associated with additional services or accounts. Depending on the system version, this item may be called Additional settings, Operator services or Calling accounts. This is where the settings for managing network functions are hidden.
After going to the operator services menu, the system may ask for confirmation or show a list of active SIM cards if the device supports Dual SIM. Select the desired SIM card and find the item Call waiting. The switch next to it should be active. If the switch is inactive (gray) or missing, this may indicate a lack of support for the function on the part of the operator or temporary problems with the network.
- 📞 Open the “Phone” application and go to the settings menu through three dots.
- 📶 Select the “Operator Services” section or “Additional settings.”
- 🔘 Activate the toggle switch opposite the “Call waiting” item.
- 💾 Wait for confirmation from the network (usually a pop-up notification appears).
☑️ Checking call settings
Sometimes after turning on the switch, a device reboot is required to apply changes at the modem level. If the function is turned on, but you do not hear a signal when you receive an incoming call during a call, check the volume of multimedia and notifications, since the waiting tone is often tied to these audio channels, and not to the volume of the speaker.
Settings through the Android system menu
If the necessary items are missing in the “Phone” application, you can try to find the settings through the global system menu. This method is especially relevant for older versions Android or specific custom firmware, where the application logic has been changed. Go to the general Settings smartphone through the gear in the notification shade.
In the list of parameters, find the section Connections or Network and Internet. Inside this section, look for subsection Mobile network. All parameters related to the operation of SIM cards, roaming and network types are collected here. In some shells, for example MIUI from Xiaomi, the call waiting item can be placed directly in the SIM card settings card.
Click on the name of your operator or item SIM card settings. The menu that opens should contain the item Additional settings or Advanced settings. It is in this hidden menu that the Call waitingswitch is often located. The system will send a request to the network, and after a few seconds the status will be updated.
| Manufacturer | Menu path | Features |
|---|---|---|
| Samsung | Phone → Settings → Additional settings | May require confirmation via a pop-up window |
| Xiaomi | Settings → SIM cards and mobile networks → Additional. settings | Separate menu for each SIM card in Dual SIM mode |
| Google Pixel | Phone → Settings → Calls → Accounts | Integration with Google account for synchronization |
| Huawei | Phone → Settings → More → Call waiting | Often hidden in a deep submenu of EMUI |
Why might settings disappear?
Sometimes after updating the firmware or resetting the settings, the network can forcefully reset the settings of additional services. In this case, re-activation is required manually or via a USSD code.
Please note that in Dual SIM mode, the setup must be performed for each card separately. The logic of the communication modules is such that activation on one SIM does not apply to the second. If you often use both lines for work, make sure that the toggle switches are turned on for both slots.
Using USSD codes to control the service
A universal method that works on any GSM-enabled phone, regardless of version Android or touch screen state, is to use USSD requests. These codes send a command directly to the operator’s server, bypassing the smartphone’s software settings. This is the most reliable method if the graphical interface produces errors.
To manage the call waiting service, standard code is used *43#. To activate the feature, open the dialer application and enter *43#, then press the call button. In response, you will receive an SMS or pop-up message from the network confirming activation. To disable the service, use the code #43#.
The current status is checked using the combination *#43#. After dialing this code and pressing the call button, the network will return a message indicating whether the service is currently enabled. This method is especially useful when purchasing used smartphones to ensure that the previous owner has not disabled important communication functions.
⚠️ Attention: USSD codes may differ for some mobile virtual network operators (MVNO) or in roaming. If the standard code does not work, check the current commands in your operator’s personal account.
Sometimes after entering the code you need to wait a few seconds, since the response from the base station may be delayed. Do not press the end call button immediately after typing, give the system time to process the request. If you receive the error “Code is invalid” or “Connection error,” try rebooting the phone and repeating the procedure.
Solving problems with parallel calls
Despite the ease of setup, users often encounter a situation where the function is enabled in the menu, but does not actually work. The second caller hears “busy”, but you do not receive notifications. One of the common reasons is a conflict with the VoLTE (Voice over LTE) function. In some networks, the implementation of call waiting in 4G mode has its own characteristics.
Try to temporarily disable VoLTE in the mobile network settings and check the function in 3G or 2G mode. If the parallel call works correctly in this mode, the problem lies in the operator’s settings for voice calls over the Internet. In this case, you should contact the provider's technical support to update the network profile.
Another common problem is the installation of third-party applications for calls, such as Truecaller or various contact “enhancers”. These apps can intercept call control and block system notifications about the second call. Try temporarily uninstalling such applications or resetting the application settings Phone through the applications menu.
- 🔄 Reboot your smartphone to reset temporary network errors.
- 📵 Turn off Do Not Disturb mode, which can jam waiting signals.
- 🗑️ Clear the cache of the Phone application in application settings.
- 📲 Check whether an anti-identifier application is blocking the second number.
If the function does not work either through the menu or through USSD codes, the most likely reason is a restriction on the part of the telecom operator or incompatibility of the tariff plan.
It is also worth checking whether forwarding to voicemail when the line is busy is activated. These two features can conflict: if forwarding takes precedence, the network will route the call to voicemail without prompting you to accept it. Disable code forwarding ##002# and test the script again.
Features of operation on dual-SIM smartphones
Owners of devices with support Dual SIM should take into account the specifics of the operation of radio modules. Most modern smartphones implement DSDS (Dual SIM Dual Standby) technology, which allows both cards to be on the network, but only one can actively receive calls at a particular time, unless the Dual 4G mode with support for simultaneous activity is used.
When you talk on the first SIM card, the second card may temporarily become unavailable for incoming calls, going into standby mode or completely disconnecting from the network, depending on the modem architecture. In such settings, a parallel call will only work for the card on which the conversation is taking place. Calls to the second card at this moment will either be dropped or redirected to voicemail.
For correct operation, you need to go into the settings of each SIM card separately and make sure that Call waiting is enabled for both slots. Some smartphones, for example from Xiaomi or Realme, have the “Allow data switching” function or similar settings that affect the availability of the second line during a call.
⚠️ Attention: On some budget smartphone models, it is impossible to support two active voice channels simultaneously in hardware. In this case, the second call physically will not be able to reach you, regardless of the software settings.
If it is critical for you not to miss calls to the second SIM card while talking on the first, consider using the “Virtual Number” service or forwarding from the second SIM card to the first. This is a software solution that allows you to redirect all calls from one number to another, creating the effect of a single line.
What is DSDS?
Dual SIM Dual Standby is a technology that allows two SIM cards to be registered in the network at the same time, but only one of them can use the radio channel to transmit voice or data at a particular time.
Frequently asked questions (FAQ)
Why can’t I hear a call waiting tone even though the feature is turned on?
Check your notification sound and media settings. Call waiting tone often uses the media audio channel rather than the speaker volume. Also make sure that in the Do Not Disturb mode, interruptions by calls are not prohibited.
Does a parallel call affect the billing of calls?
Yes, if you switch to the second subscriber, the first call is put on hold. Billing is usually per minute for each active connection. Conference calls can be charged as two separate conversations simultaneously.
Is it possible to set up a parallel call via a computer?
No, this service is managed at the level of the SIM card and network profile. A computer cannot send the necessary signals to the cellular network without connecting the phone as a modem and using specific software, so it’s easier to do this from the device itself.
Does call waiting work in roaming?
In most cases, yes, if your home operator has entered into appropriate agreements with foreign partners. However, in some countries the service may not be available or may cost additional money. It is better to check the roaming conditions before your trip.
How to turn off the sound of the waiting signal, but leave the function?
Unfortunately, using standard Android tools you cannot turn off only the sound, leaving a visual notification. The signal is a mandatory attribute of the GSM protocol. The only option is to use third-party applications for calls that can replace system sounds.