Field Test Mode is a hidden feature on the iPhone which allows you to see technical details of the device, the most useful of which is the true cell signal strength displayed as a number rather than the traditional signal bars or dots.
So you can switch between the standard dots/bars
Or numeric value
Here's how:
* Dial *3001#12345#* and hit “Call” if you haven’t done so already to launch Field Test
* Now hold down the Power button until the “Slide to Power Off” message appears, then release the Power button and hold the Home button until Field Test quits
* Tap the signal bars or signal numbers to switch between the two
To always see the signal numbers rather than the signal bars or dots, you’ll use the Force Quit app function to kill Field Test when it’s open.
To remove the tap-to-switch signal indicator ability, you can either reboot the iPhone or go back into Field Test and close out of it as usual.
To return to the default bars permanently, follow these steps:
Step 1: Dial *3001#12345#* on your iPhone then press Call.
Step 2: Press on your Home Button once.
This trick may come in handy when you're in a dead zone and need to know where to move to for a better signal.
Note: Be sure to include all the characters ( the * and #) in the number.
Also remember the numbers are negative. So -80 is better than -110.
Field Test Mode is a hidden feature on the iPhone which allows you to see technical details of the device, the most useful of which is the true cell signal strength displayed as a number rather than the traditional signal bars or dots.
