Users of modern smartphones are often faced with a paradoxical situation: a device that should be intuitive, sometimes hides basic functions behind layers of app code. One of these problems is the inability to dial the hash symbol or number, which in the international system is designated as hash sign. This sign is critical for entering USSD codes, activating voicemail or setting up call forwarding.
The problem does not arise due to a breakdown of the phone, but due to the localization of the keyboard or malfunctions in the “Phone” system application. In some regions, the "*" and "#" characters are moved to additional input screens, while in other cases they are blocked entirely by your carrier or security settings. Understanding how where exactly to look for this symbol saves a lot of time and nerves.
In this article we will analyze all possible scenarios: from the standard button layout to hidden engineering diagnostic menus. You will learn why the button disappears at a specific point in time and how to return it to the screen without rebooting the device. We will also touch on the topic of security, since entering special characters can open access to hidden system functions.
Standard key layout in the Phone application
In the vast majority of cases, when you open the standard application for making calls, the number sign is located in the bottom row of the numeric pad. It is usually located to the right of the zero or in the lower right corner of the button grid. However, the interface may vary depending on manufacturer's shellsuch as One UI from Samsung or MIUI from Xiaomi.
If you do not see the symbol right away, try switching the dialing mode. Some smartphones by default open the Contacts or Recents tab, where the number pad is hidden. You need to tap on the keyboard icon, often indicated as Keypad or an image of buttons, to expand the full input interface. Only in this mode do service symbols become available.
Sometimes the “#” button is visually different from the numbers. It can be painted a different color or be smaller in size so that the user does not accidentally press it during normal typing. Pay attention to the bottom line: service signs are often located next to the call button (green tube). If there is only “*”, then the hash is hidden at the second input level.
On some smartphone models, the number sign appears only after pressing the first digit. Try typing any number, for example “0”, and check if the keyboard layout has changed.
It is worth considering that when dialing an international number, the keyboard format may change. When you enter the “+” symbol (usually a long press on “0”), the system can automatically rearrange a number of buttons, making the “#” sign more accessible for entering country and operator codes.
Problems with display in different launchers and shells
Android shell developers often strive for minimalism, removing “extra” elements from the main dialing screen. This creates confusion, especially for those who have recently switched smartphone brands. For example, on devices Google Pixel the interface is as clean as possible, while on Huawei or Honor the buttons can be grouped differently.
In some custom firmware, the number sign is moved to the second page of the keyboard. To get to it, you need to swipe left on the numeric pad or press the special character switch button, often indicated as ?123 or an arrow icon. This solution is used to free up space for buttons for quick access to contacts.
⚠️ Attention: If you have installed a third-party application for calls from Google Play, it may have its own button layout logic. In such applications, the “#” sign is sometimes hidden in the call settings menu or is only available in the “Engineering Test” mode.
There is also a problem with interface scaling. On smartphones with a small screen or when the “Text Enlarge” mode is turned on, the buttons may overlap each other, making the license plate invisible or unclickable. In such a situation, temporarily reducing the font in the settings will help. Screen → Font size.
Using the number sign for USSD requests
The main purpose of the “#” symbol in mobile communications is the formation USSD commands. These requests allow you to instantly receive information about your balance, traffic balance, or connect services without access to the Internet. The command always starts with an asterisk, contains numbers and ends with a hash, for example *100#.
When entering such codes, it is important to follow the sequence. If you press the call button before entering the terminating “#” character, the system will try to call an incomplete number, resulting in a connection error. Smartphones with the Automatic Dial feature may try to send a request ahead of time, so sometimes you need to disable this option in the settings.
Below is a table of common commands where the use of a number sign is a prerequisite for completing the request:
| Operation | Command example | Result |
|---|---|---|
| Check balance | *100# |
Account information |
| Disable service | *111*8# |
Deactivate subscription |
| Enter menu | *111# |
Main service menu |
| Change tariff | *111*23# |
Activate a new plan |
If, when entering the command, the “#” sign is not pressed or disappears, the problem may be on the side of the telecom operator. Some virtual operators block the entry of special characters while roaming or with a negative balance. In this case, you should try entering the command through the services menu in the operator’s personal account.
☑️ Diagnosing a problem with USSD
Secret codes and engineering menu
The number sign is the key to hidden sections of the operating system Android. The engineering menu allows you to diagnose sensors, check communication quality and reset network settings. These functions are accessed through special combinations starting and ending with the characters “*” and “#”.
The most famous code is ##4636##. It opens the testing menu where you can see battery information, usage statistics, and Wi-Fi settings. Entering this sequence requires fast and accurate operation of the keyboard, as some phones do not display the entered characters on the screen for security.
⚠️ Attention: Changing parameters in the engineering menu may lead to unstable operation of the phone or loss of the network. Do not change the values unless you are sure of their purpose, especially in the sections Radio Information.
There are other manufacturer-specific codes. For example, on devices Samsung the combination #0# runs a full screen and sensor test. On Xiaomi code ##6484## opens a similar Cit menu. The number sign is critical for entering these commands, and its absence on the keyboard makes diagnostics impossible.
What to do if the code does not work?
If entering the secret code does not produce any action, your carrier may be blocking interception of such calls. Try entering the code in flight mode or through the “Engineering Mode” application, downloaded separately.
Alternative methods for entering a character
When the standard phone keyboard does not allow you to enter a number character, alternative methods come to the rescue. The first one is using a third-party keyboard. Applications like Gboard or SwiftKey have flexible layout settings that allow you to place the “#” symbol on the main screen or add it to the symbol panel.
The second method is to copy the symbol from the clipboard. You can find the "#" sign in any text, message or in this article, copy it and paste it into the dialing field. To do this, you need to highlight the character, click “Copy”, then in the “Phone” application, hold your finger in the input field and select “Paste”.
The third option is to use voice input. While dictating a number or hash symbol doesn't work in all apps, in some system fields, Google Assistant can recognize the "enter number sign" command and substitute the desired character. This is convenient if the touch screen does not work correctly.
- 📋 Copy a character from a message or browser and paste it into the typing field.
- ⌨️ Install the Gboard keyboard and add the “#” symbol to the number row through the settings.
- 🎙️ Try dictating the character through voice assistant, if supported.
You can also use the “Accessibility” function. There is a menu in Android settings that allows you to create your own layout or add frequently used symbols to the quick access panel. This solution is suitable for users who constantly need to enter complex combinations.
Configuring the keyboard and restoring characters
If the number character suddenly disappeared, there may have been a failure in the input settings. Go to Settings → System → Language and input. Select your active keyboard and check the "Layout" or "Symbols" section. Make sure that the limited input mode is not activated, which is often enabled in child profiles or guest modes.
In some cases, clearing the cache of the Phone application helps. Go to Settings → Applications → Phone → Storage and click "Clear cache". This will not delete your contacts or call history, but it will reset temporary interface files, which may bring back the missing button.
⚠️ Warning: Before resetting your keyboard, make sure you remember your primary input language. After the reset, you may need to re-configure the dictionary and predictive input.
If all else fails, check system updates. Errors with the display of characters are often bugs in a specific firmware version, which are fixed by developers in security patches. Updating the software to the latest version can automatically solve the problem with the missing sign.
Restoring the “#” button is most often achieved by resetting the keyboard settings or updating the Phone application to the latest version.
Frequently asked questions (FAQ)
Why the number sign is not pressed when typing USSD code?
This may be due to blocking by the telecom operator while roaming or due to a lack of funds in the account. Also check if the “Emergency calls only” mode is enabled.
Is it possible to change the keyboard layout in the Phone application?
In the standard application, you cannot change the layout, but you can install a third-party app for calls from Google Play, which allows you to customize the input panel.
Where the number sign is located on Android tablets?
On tablets without a phone module, this symbol is only available in VoIP or calculator applications. In the system keyboard, it is located on the symbols page ?123.
What should I do if the secret code resets the settings?
Some codes actually initiate a reset. If you accidentally enter such a code, cancel the action immediately if there is a “Cancel” button. If the reset occurs, you will need to reconfigure the device.