The iPhone, known for its intuitive interface and robust functionality, holds secrets beyond the reach of its standard settings app. These secrets lie within USSD codes, a series of hidden commands that grant users access to a deeper level of control and information.

USSD codes, short for "Unstructured Supplementary Service Data," are hidden passcodes that unlock a range of functionalities on your iPhone. These codes, once more prevalent in the era of less sophisticated settings applications, still hold value for quick access to advanced features and detailed information.

With these codes, you can:

• Check your International Mobile Equipment Identity (IMEI).
• Manage call forwarding and caller ID settings.
• Access detailed network information.
• Modify call waiting and blocked number settings.
• Engage field test mode for technical insights.

Utilizing these codes is straightforward:

• Open the Phone app.
• Tap on the Keypad tab.
• Enter the desired code. Some codes trigger actions immediately, while others require pressing the Call button.

Here are some widely used codes:

• IMEI Check: *#06#
• Hide Caller ID (USA): *67[phone number]
• Hide Caller ID (International): *31#[phone number]
• Network Information: 3001#12345#
• Call Waiting: *#43#
• Call Forwarding: *#21#
• Blocked Numbers: *#33#
• Forward Calls: *21[phone number]#
• Show Caller ID: *82[phone number]
• Field Test Mode: 3001#12345#
• Missed Calls: *#61#
• Block/Unblock Calls: 33 / #33* [SIM PIN] #
• Alert System Status: 500525371# / 500525370#
• Offline Traffic Info: 511
• Account Balances: *777# (Prepaid), *225# (Postpaid)
• Data Plan Status: *646#

Unfortunately, there's no one-size-fits-all USSD code to revert changes. If an adjustment causes issues, you must manually undo each change. For irreversible errors, a factory reset might be necessary.

To factory reset:

1. Open Settings.
2. Go to General.
3. Select Transfer or Reset iPhone.
4. Choose Erase All Content and Settings.
5. Follow the prompts to complete the process.

iPhone's secret codes offer a unique peek into the more technical aspects of your device. While they aren't necessary for everyday use, knowing these codes can enhance your understanding and control over your iPhone. Remember, with great power comes great responsibility – use these codes wisely!