MMI (Man-Machine Interface) codes are special codes entered on your phone to access hidden menus and network information. They are sometimes called USSD codes or shortcodes, and they allow users to perform tasks like checking balance, call forwarding, or device information without navigating through menus.
How MMI Codes Work
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MMI codes are a communication interface between your phone and the mobile network.
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They usually start and end with symbols like
*and#. -
When entered, the phone sends a request to the network or activates a function in the device.
Common Uses of MMI Codes
1. Check Balance or Data
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Example:
*123#can show prepaid balance on many carriers.
2. Manage Call Forwarding
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Activate or deactivate call forwarding with codes like
*21*or#21#.
3. Check Device Information
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Codes like
*#06#display your phone’s IMEI number. -
Useful for warranty, carrier support, or device verification.
4. SIM and Network Settings
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Check SIM status or lock/unlock SIM using network-specific MMI codes.
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Troubleshoot network connection issues quickly.
5. Access Hidden Menus
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Some phones allow access to diagnostic or testing menus via MMI codes.
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Useful for checking hardware functions like display, sensors, and touch responsiveness.
How to Use an MMI Code Safely
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Open the phone’s dialer app.
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Enter the code exactly as provided, including
*and#. -
Press Call/Send to execute the code.
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Avoid random codes from untrusted sources to prevent device or network issues.
Limitations of MMI Codes
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Not all codes work on every device or carrier.
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Some codes may be disabled by the carrier for security reasons.
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Incorrect usage can trigger unintended settings, so use trusted sources only.
Conclusion
MMI codes are powerful shortcuts to access network and device information on your smartphone. By understanding their purpose, common uses, and safe practices, you can efficiently manage your mobile device and network settings without navigating through complicated menus.