Every owner of a smartphone based on Androidcan encounter a situation where an incoming call is displayed as “Unknown number” or “Hidden number”. This causes not only curiosity, but also often anxiety, especially if the calls are repeated regularly. Many users immediately wonder if there is a magic button or secret code that will instantly reveal the identity of the caller. Unfortunately, the reality is somewhat more complicated, and the mechanisms for hiding a number work at the level of the cellular operator, and not just your device.

Nevertheless, there are effective ways to combat anonymity, ranging from standard system settings to the use of specialized USSD commands and third-party software. It is important to understand that methods that work on one device may not be useful on another due to differences in firmware and carrier policies. In this article, we will analyze in detail the technical aspects of detecting hidden subscribers and offer step-by-step guide for various scenarios.

Before moving on to radical measures, it is worth checking the basic settings of your smartphone. Often the problem lies not in the caller's cunning schemes, but in the way your phone processes incoming signals. Let's look at the main tools that will help you regain control of your contact list and understand who is actually trying to call you.

Using USSD codes to control number display

The fastest way to check the transfer status of your number and try to influence the display of other people's numbers is to use USSD requests. These commands are sent directly to the cellular operator's server, bypassing the smartphone interface. They work on any device, even if the screen is locked or the phone is in standby mode.

Telecom operators provide special codes for activating and deactivating the Caller ID service. If you want to make sure that your number is open, or try to force a request to display the number of your interlocutor, you can use the following combinations. However, remember that there is no universal code for “hacking” someone else’s hidden number due to GSM security protocols.

⚠️ Attention: Some USSD codes may be paid or require prior activation of the service from the operator. Before entering complex combinations, check the tariffs in your personal account of your communication provider.

To manage your own identification for outgoing calls, standard codes regulated by the GSM standard are used. You can temporarily open your number even if the settings are set to hide, or vice versa, hide it for a specific call. This helps to diagnose whether the number identification function works in principle.

*31# - activation of number transmission (default)

#31# - deactivation of number transmission (hiding)


*31*phone_number# - call with an open number

If you If you want to check whether the hidden number service is activated on your SIM card by default, use the code *#31#. After typing this command and pressing the call button, the system will display the service status. In some cases, operators offer the Anti-Caller ID service, which allows you to see hidden numbers for a fee. Activation of such a service is also carried out through the USSD menu, the code of which is individual for each operator (MTS, Beeline, Megafon, Tele2).

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If standard codes do not work, go to the “My Operator” application or call support. Often, managing number hiding services is only available through your personal account or the operator’s proprietary application.

Smartphone settings: how to allow the display of hidden calls

The operating system Android has built-in call filtering mechanisms. Sometimes users accidentally activate the block all unknown numbers mode, which creates the illusion that the numbers are hidden, when in fact they are simply blocked by the system. To fix this, you need to delve into the settings of the Phone application.

The settings interface may differ depending on the manufacturer's shell (MIUI, OneUI, ColorOS), but the logic remains the same. You need to find the section responsible for additional call settings. Here you can allow the display of numbers that were hidden by the sender, if the data network allows it.

  • 📱 Open the application Phone (green handset).
  • ⚙️ Tap on the three dots in the corner of the screen and select Settings.
  • 📞 Go to section Additional settings or Operator services.
  • 👁️ Find item Subscriber Identification or CLIR.

In the menu CLIR (Calling Line Identification Restriction) you will see three options: “Default Network”, “Hide Number” and “Show Number”. Selecting the “Show number” option sends a request to the operator to force the transfer of your ID. Likewise, if you have superuser rights (Root) or special engineering access, you can try to change the parameters for processing incoming signals so that the phone does not ignore data packets with a hidden ID.

It is worth noting that on modern versions of Android (starting from 10 and higher), Google has limited direct access to some phone functions for third-party applications. Therefore, the settings built into the system compositor are the most reliable tool. If this menu does not have the necessary options, it means that your operator does not support controlling this function via handset commands, and all actions must be performed through the SIM menu or calling support.

☑️ Checking call settings

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Determinator applications and spam databases

When built-in tools are powerless, specialized applications such as Getcontact, NumBuster or Truecallercome to the rescue. These services work on the principle of crowdsourcing: they collect databases of numbers from millions of users. If one of the contacts of this “someone” has saved a hidden number under the name “Courier” or “Pushy Salesman”, the application will show you this name.

The principle of operation of such apps is based on the analysis of call metadata. Even if the number is hidden from the network, at the time the connection is established, the device can receive certain signatures that are checked against the global database. This does not guarantee 100% identity disclosure, but it significantly increases the chances of finding out who is calling, especially if it is a mass call or spam.

However, using such services carries privacy risks. By installing such an application, you often provide access to your address book, thereby transferring the contacts of your friends and colleagues to a common database. This is an ethical point that should be taken into account before installation.

Application Working principle Determination accuracy Privacy risks
Truecaller Global database + spam filter High High (access to contacts)
Getcontact User tags Medium/High Medium (book synchronization)
Kaspersky Who Calls Database of known scammers Medium Low (local check)
NumBuster Social network search Low/Medium Medium

For maximum efficiency, it is recommended to combine several applications. For example, one identifier may not know the number that is in the database of another. Also, many of these apps allow you to automatically reject calls from subscribers marked as “Spam”, which solves the problem of annoying calls without the need to find out your identity.

📊 What application for identifying numbers do you use?
Truecaller
Getcontact
Kaspersky
I do not use applications
Other

Engineering menu and hidden settings Android

For advanced users there is access to engineering menu (Engineering Mode). This is a hidden section of the system intended for testing equipment and configuring network parameters. Through it you can access call logs and more detailed network settings that are not visible in the regular interface.

Entering the engineering menu is done through special codes in the dialer. The most common commands for devices on processors MediaTek and Qualcomm are different. Be extremely careful: changing incorrect parameters in this menu can lead to loss of connection or unstable operation of the smartphone.

##4636## — Testing menu (standard Android)
##3646633## — MediaTek engineering menu
##197328640## — Samsung service mode

Once in the menu, you need to go to section related to telephony (Phone Information). Here you can try to force CLI (Calling Line Identity) display. Look for options like "Force CLIR" or network type settings. Sometimes switching network mode with LTE only to WCDMA/GSM and back helps to reset network settings and update the service profile of the operator, which can return the number identification function.

⚠️ Attention: You change parameters in the engineering menu at your own peril and risk. Do not change values ​​unless you are sure of their purpose. Take a screenshot of the initial settings before making changes.

Also in the Call Logs available through some developer utilities, you can sometimes see technical information about the incoming connection that is not displayed in the standard log. This requires connecting the phone to the computer and using USB debugging (ADB), which is a method for advanced users.

What to do if the code does not work?

If entering the engineering menu code does not open anything or gives the error “Command is not valid,” then your smartphone manufacturer has blocked this access. This is common on Xiaomi, Huawei and new Samsung models. In this case, it is better not to try to install third-party applications to log into the engineer, as they may contain malicious code.

Request call details from the operator

The most legal and reliable way to find out the number of a hidden subscriber is to contact your cellular operator. In emergency cases such as threats, blackmail or fraud, telecom operators are required to provide caller information when requested by law enforcement. However, for ordinary users the procedure is simplified, but has its limitations.

Many operators offer the “Call Details” service, where all incoming and outgoing connections are displayed. In standard detail, hidden numbers are often indicated by a dash or the word “Anonymous.” But there are special tariff options or one-time services that allow you to reveal the number of the last anonymous caller. For example, the AntiAON service or similar services.

To activate such services you usually need:

  • 📞 Call the support service from your number.
  • 🆔 Go through personal identification (state the code word or passport data).
  • 💳 Confirm your agreement to pay for the service (if it is paid).

It is important to understand the difference between a “hidden number” and a “spam call”. The operator always sees the number on its network, even if it is not transmitted to the device. Therefore, there is always a technical possibility to reveal the number. The only question is whether the operator has the right to transfer this data to you without a court decision or a special request. In most cases, for a one-time disclosure of a number, a written application to the communication salon is sufficient.

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The telecom operator sees all numbers, even hidden ones. Disclosure of information to third parties is regulated by communications and personal data legislation, but the procedure has been simplified to protect against threats.

The issue of privacy in telephony is regulated by strict laws. On the one hand, the subscriber has the right to anonymity, on the other hand, to security and protection from harassment. Attempts to use “hacking” methods or illegal databases to punch numbers can lead to a violation of the law on personal data.

Using gray schemes, such as buying databases on the darknet or exploiting vulnerabilities in telephony (SS7 attacks), is illegal. Moreover, such methods often turn out to be scams where you lose money but do not gain information. It is safer and more effective to act in the legal field.

If hidden calls are of a stalking nature:

  1. Fix the time and date of the calls.
  2. Contact the operator to block anonymous calls (the "Banning Anonymous Calls" service).
  3. In case of threats, write a statement to the police - employees of the Ministry of Internal Affairs have the authority to request complete information from the operator instantly.

Remember that complete anonymity in the digital environment is a myth. Any signal that passes through a cell tower leaves a trace. The main task of the user is to use legal tools to protect his peace of mind, without violating the rights of other citizens without good reason.

⚠️ Attention: Legislation and operator tariffs may change. Always check the latest information about available services for revealing numbers and blocking spam on the official website of your operator or at the sales office.

Is it possible to find out the number if the caller used Internet telephony?

Find out the caller’s number through instant messengers (WhatsApp, Telegram, Viber) or IP telephony, if it is hidden, almost impossible through standard means. These services use encryption and do not transmit the number in normal telephone format. Determination is only possible if you have the contact of this person in your address book, and the application will pull the name from it.

Why does the *31# code not work on my phone?

The code may not work for several reasons: the service is already activated by default, your operator uses a different combination of characters, or the SIM card does not support service management via USSD (rare). Try restarting your phone or checking your account balance.

Is it safe to install applications like Getcontact?

Applications are safe from viruses if downloaded from the official Google Play store. However, they are not secure for your privacy as they upload your notebook to their servers. Use them with caution and delete them after use if you are concerned about your friends' data.

Can an operator completely block me from calling hidden numbers?

Yes, many operators provide the “Banning incoming calls from hidden numbers” service. When activated, calls from subscribers who hide their ID will simply not go through to your phone, and the caller will hear a busy signal or an error message.