How to put an iPhone into Field Test Mode (FTM)

This method puts the iPhone into temporary FTM when in a call (it can be done while in the idle "non-call" state but the information will not be as useful)

  • Make a call to a phone and leave the call up
  • Hide Keypad
  • Add a call
  • Select keypad input
  • *3001#123435#* [Call]
  • Now in the menu it’s UMTS>Neighbors>Active Set>0 (this is for WCDMA/UMTS services and LTE will be slightly different)

Another nice feature of the FTM is that your signal "bars" are replaced with actual pilot channel power level in dBm (mWatts in decibels of power which is the common signal measure of merit as follows:

  • For WCDMA/UMTS, -110 dBm would be very low, -100 is ok, and above -80 would be very good).
  • For LTE service, -120 dBm would be very low, -110 is ok, and above -90 would be very good).

If you would like to be able to permanently see the dBm signal level rather than bars on your iPhone (you can actually tap on the icon to toggle between bars and dBm) you can do the following:

  • Enter the FTM as above
  • Hold down the Power button until "Slide to Power Off" appears and keep holding
  • Now while still holding the power button down, also press and hold the Home button
  • Immediately when the screen flashes to the main screen, let go the power button and then the Home button.
  • If your timing is wrong your iPhone may reboot and you can just try again.
  • If successful you will always be able to tap the bars/dBm icon without having to be in FTM.
  • To undo the mode, reboot the handset or enter FTM again and it will reset.







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