Field Test Mode is a function found on devices allowing access to technical data regarding your cellular connection. It can be used for troubleshooting, diagnostics, and testing.
1: Open the Phone app.
2: Select the Keypad option in the bottom menu.
![](https://techelper.io/wp-content/uploads/2020/07/ftm-iphone-4-1024x175.png)
![](https://techelper.io/wp-content/uploads/2020/07/ftm-iphone-2-473x1024.png)
3: Key in the numbers/symbols: “*3001#123453*“
![](https://techelper.io/wp-content/uploads/2020/07/ftm-iphone-3-473x1024.png)
4: Press the call button to enter the Field Test app.