Ok – so you want to replace your iPhone signal bars (boring) to the more accurate decibel meter, this is super simple…aka iPhone signal numbers instead of bars.
Step One: Press and launch Phone app from your Home Screen:
Step Two: Tap the keyboard tab then dial *3001#12345#*
*Your iPhone will now launch into Field Test Mode (you’ll notice the signal strength meter appearing)…
Step Three: Press and hold the Power button (not the home button) until the power slider appears.
Final Step: Press and hold the Home button until the Field Test program is terminated.
It’s that easy, now you can enjoy knowing exactly how strong your cell tower signal is!
Remember: To remove the signal strength numbers, simply go back into Field Test mode from step 1 above and hit the Home button to exit Field Test mode >> the familiar and boring five dots will remain.