iPhone 4 signal strength in dBm?

Discussion in 'iPhone' started by firewood, Jun 24, 2010.

  1. macrumors 604

    Jul 29, 2003
    Silicon Valley
    Anyone know how to get a read-out of the current cellular signal strength in dBm on an iPhone 4?
  2. macrumors newbie

    Apr 8, 2009
  3. macrumors regular

    Jul 14, 2008
    For some reason I can click on my bars and it swaps from bars to dbm on my iphone 4. This has happened ever since I had backed up my Jailbroken 3GS while it was showing dbm.

    Every restore from backup (non jailbroken) from there on out resulted in the dbm option without punching in any type of code.

    It's weird, but I love it. I noticed that the iPhone 4 sometimes shows 2 bars at -113.
  4. macrumors 6502

    Jul 2, 2007
  5. macrumors newbie

    Nov 30, 2009
    Well, this used to work, but now it doesn't seem to be.

    But give it a shot either way I guess:

    Access the iPhone’s Field Test mode by typing *3001#12345#* in the phone’s keypad and press dial. This will bring up the Field Test menu.
  6. macrumors newbie

    Oct 1, 2009
    Use ^ that sequence but on a phone with lower than iOS4 and while in the field test mode
    if on 3.x.x hold sleep button until it prompts to shut off then let go and hold the home button until it force quits the field test mode.
    if on 2.x.x hold home button until force quit

    make a back up on itunes and then restore from that back up on the iphone 4. You will just need to touch the signal to switch between bars and dBm
  7. macrumors 6502

    Sep 12, 2007
    RF meter/multimeter. Bench test or using the machines that were used in production.

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