iPhone secret codes are also known as Unstructured Supplementary Service Data codes (USSD). These are shortcuts and access codes to enter unique settings and functions within the device.

Type USSD codes on your iPhone to access hidden cellular features quickly. Here, we'll list some of the most useful ones. advertisement. MUO. 11+ Secret iPhone Codes You Need to Try.

Some secret codes will work on your iPhone with your carrier, but some will not. The only way to truly find out is to give them a go. Here, we list some other USSD codes that you could try.

One of the most interesting of the USSD codes is the Field Test mode, which allows users to see their phone-signal strength measured in numbers rather than those five bars.

Hiding caller ID You can hide your Caller ID by using a USSD code before dialling the phone number you are going to call. First, enter #31# (if you are in US dial *67), then enter the person's ...

Forward All Calls: To forward all calls coming to your iPhone, dial the following USSD code: *21*PhoneNumber# Forward Calls When Busy: If you want to forward calls when your phone is busy, ...

These codes combine different technologies and protocols, including Unstructured Supplementary Service Data (USSD), manufacturer-defined MMI (man-machine interface), and supplementary service (SS ...