Secret Hack Codes for iPhone 4 or iPhone 4S

*#43#   

Use to verify if call waiting is enabled

*#61#  

Verify the number for unanswered calls

*#62#   

Verify the number for call forwarding if no service is available.

*#67#   

Verify the number for call forwarding if phone is busy

*#33#  

To verify whether barring is enabled or disabled for outgoing

*#21#   

To display the settings for your call forwarding

*3001#12345#*

Enters Field mode which allows you to access most of the hidden settings and functions of your iPhone.

*#06#     

Display the IMEI of your iPhone, as always this is the standard code for all brands of phones.

*225#    

Displays the account balance for postpaid contracts.

*777#     

Displays the account balance for prepaid accounts.

*646#     

Displays the remaining minutes available.

*3282#     

Get your data usage information.

*729     

Options to make payments. Its operator specific.