iOS 14 includes redesigned field test mode

Apple’s upcoming iOS 14 update introduces multiple design changes, including a new look at the hidden field test mode feature on iPhone.

As noted in the MacRumors Forums, Apple has revised the field test mode to provide more useful information at a glance.

Field test mode in OSiOS 14‌
There is now a home section with LTE cell service information, along with a menu section that has other details like device information and breakdowns of LTE, UMTS and GSM functionality.

Much of the information available on iOS 13 and ‌iOS 14‌ is the same when it comes to field test mode, so the change is mostly related to design and makes it easier to navigate through the hidden app.

The field test mode is designed to allow PiPhone‌ users to access detailed information about cellular signal and cellular connection. The field test mode is designed for engineers and cell phone operators and most people will not need to use it on a regular basis.

Field test mode in OSiOS 14‌
You can access the field test mode on an ‌iPhone‌ by opening the Telephone application, entering * 3001 # 12345 # * and pressing the telephone button. It will not make a call, but will open the Field Test application.

The field test mode was previously useful because it could convert cellular signal bars into a numerical measure, but that’s not something that works on modern iPhones with recent versions of iOS.

Field test mode in OSiOS 13‌
Sometimes it may be useful to see the cellular signal represented as a number, and it is still possible in ‌iOS 13‌ and 14. After entering the Field Test app, tap LTE (from the main menu in ‌iOS 13‌ or the menu list in OSiOS 14‌) and then tap “Serving Cell Meas”.

The measurements that read “rsrp0” and “rspr1” are the power of your cellular signal in decibels-milliwatts. These numbers are always negative, and a lower negative number is better than a higher negative number and represents a stronger connection. The numbers range from about -50 to -130. Closer to -50 is a strong signal strength, and when you get to around -100, that’s a poor connection that’s erratic with slow data rates if a connection can be made.