Your smartphone is much more than a device for calls, messaging, or social media. Hidden within it are powerful diagnostic menus and secret codes that reveal system information, help troubleshoot problems, and unlock advanced settings.

These codes, known as USSD (Unstructured Supplementary Service Data) or MMI (Man-Machine Interface) codes , are useful for tech enthusiasts and everyday users alike. In this guide, we'll explore the most practical secret codes for both Android and iPhone devices.

Universal Smartphone Codes

These codes work across most devices, regardless of brand or operating system.

* Check Your IMEI Number: #06#
The IMEI (International Mobile Equipment Identity) is a 15-digit unique identifier for your device. Display it instantly using this code.

• Track a lost or stolen phone

• Verify your phone's authenticity

• Assist network support and troubleshooting

Hide Your Caller ID: #31# + Phone Number
To make an anonymous call, dial #31# before the recipient's number.
For permanent changes, adjust Caller ID in your phone's settings.

Android Secret Codes

Android devices have a wide range of codes that provide access to system information, hardware tests, and advanced menus.

Phone Information and Battery Health: # #4636# #
Opens the Testing Menu, showing device details, Wi-Fi usage statistics, and battery information including health, temperature, and voltage. Understanding these stats helps optimize battery performance.

General Hardware Test: #0 #
Run tests on your phone's hardware, including:

• LCD screen (dead pixels)

• Touchscreen responsiveness

• Speakers and microphones

• Front and rear cameras
  Note: Primarily works on Samsung Galaxy devices.

Service Menu Access: # #197328640# #
Advanced diagnostics include viewing signal strength, modifying network settings, and running hardware tests. Caution: Incorrect changes may affect device functionality.

Hard Reset (Factory Reset): # #7780# #
Performs a factory reset, wiping all apps, settings, and personal data. Always back up your device before using this code.

Additional Useful Android Codes

• GPS Test: # #1472365# #

• Bluetooth Test: # #232331# #

• Proximity Sensor Test: # #0588# #

• Vibration and Backlight Test: # #0842# #

• Display Software/Hardware Version: Samsung: #1234# / Software: ##1111# #* / Hardware: # #2222# #

iPhone Secret Codes

iPhones are more restricted, but some USSD codes provide useful information.

Field Test Mode: 3001#12345# → Call
Displays technical network data such as signal strength in dBm and the connected cell tower. Useful for troubleshooting weak reception.

* Check Call Forwarding Status: #67#
Shows the number receiving calls when your line is busy, typically voicemail, which can be changed if desired.

Conclusion

Secret smartphone codes are powerful tools that allow you to:

• Check your device's health

• Test hardware components

• Troubleshoot network or system issues

Use these codes responsibly, especially those that can reset or alter settings. With this knowledge, you can unlock your smartphone's full potential and become a true power user.