Is NFC a battery drain at all?

Discussion in 'iOS 8' started by Steve686, Oct 20, 2014.

  1. Steve686 macrumors 68030

    Steve686

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    #1
    Not sure if NFC is a battery drain for those who do not want to use it. I know you can use it even when the screen is locked, and I loved that feature. Makes it absolutely flawless.

    I assume it's a very, very low output signal, hence, Near Field...

    But, is there also a way to turn it off? And does Airplane Mode turn it off?(Forgot to check this when I did a couple of :apple:Pay transactions earlier today.
     
  2. Intell macrumors P6

    Intell

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    #2
    It is only turned on and used when preforming a non-in app Apple Pay transaction. At all other times, it is turned off. Even when on, it uses very little power.
     
  3. Steve686 thread starter macrumors 68030

    Steve686

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    #3
    But how is it activated from lock screen, then? There has to be a signal that wakes the NFC radio? But in order to do that, wouldn't the NFC radio already be required to be on/receiving?

    I know it uses very little power, I just want to know exactly what activates Apple's particular NFC modes.
     
  4. Intell macrumors P6

    Intell

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    #4
    It's activated by you preforming a transaction with TouchID.
     
  5. Steve686 thread starter macrumors 68030

    Steve686

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    #5
    Negative.

    I held my locked phone up to the NFC reader, and my phone awoke to complete the transaction. THEN, you use the TouchID.

    The process somehow is like a handshake wirelessly.
     
  6. Intell macrumors P6

    Intell

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    #6
    Don't forget that NFC is also passive in nature. It will and can receive a wake up signal without needing any power. It will only transmit once a transaction is taking place. All while using such a small amount of power it isn't even worth comprehending.
     
  7. Steve686 thread starter macrumors 68030

    Steve686

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    #7
    Ya. I was just very curious about the wake up procedure.
     

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