There are many secret codes to activate hidden iPhone features. Most are for application developers. However, any iPhone owner should at least know the four most practical hidden features …
Hide your call number
Whether it's to make a bad joke for someone close to you, or to avoid giving your number to a stranger, hiding your phone number can be useful in everyday life. It is possible to activate this function in seconds in iOS, by entering the characters # 31 #, followed by the correspondent's telephone number on the dialing screen. The masking will disappear as soon as you make another call.
Know your IMEI number
The IMEI number is the unique identification number for your iPhone. To find out, simply type the characters * # 06 # with your keyboard and the iPhone will magically show the unique identification number of your device. This will allow you to block your smartphone remotely, in the event of theft or loss.
Activate / deactivate call waiting
By entering the characters * 43 # with your keypad on the dial screen, you will activate a call waiting feature that will allow you to pause a call to answer a second call. The function can be easily deactivated in the same way, with the code # 43 #.
Divert all calls to your mailbox
If you are busy on your mobile, and do not want to leave a correspondent who would call you to know that you have just hung up on him, there is a secret function which allows you to activate the automatic forwarding of calls to your messaging system, very practical at daily, and above all easily deactivated. This time you just have to press the code # # 21 # on the dial screen of your iPhone to activate it.