Using GSM in stead of 3G when calling

Discussion in 'iPhone' started by Mikegs, Aug 19, 2010.

  1. Mikegs macrumors regular

    Joined:
    Aug 6, 2010
    #1
    Hello

    I'm on my first Iphone, it's iphone 4

    On my previous phone there was an option to use GSM in stead of 3G when calling in order to save battery. Is this possible with the Iphone?

    Thanks

    PS: The ability to use data on 3G was retained even when forcing calls to GSM mode only
     
  2. jav6454 macrumors P6

    jav6454

    Joined:
    Nov 14, 2007
    Location:
    1 Geostationary Tower Plaza
    #2
    Yes there is.

    Settings => General => Network Settings

    then just flick the switch and go into GSM/GPRS/EDGE mode.


    3G capabilities die when you do that. Flick the switch back to get 3G back. Also, doing so requires reset of the CommCenter which means in a call it will drop the call.
     
  3. Mikegs thread starter macrumors regular

    Joined:
    Aug 6, 2010
    #3
    Sorry, what switch?

    In Settings-General-Network the following switches are present (or something similar - i am translating from danish)

    "mobile data"
    "Data roaming"
    "Internet sharing"
    "VPN"
    "Wi-Fi"

    And none of those has settings regarding GSM/GPRS/EDGE

    Please clarify
     
  4. Drag'nGT macrumors 68000

    Drag'nGT

    Joined:
    Sep 20, 2008
    #4
    Under network choose to turn 3G off. It's gonna put you on the edge network and it will increase your call time.

    Personally it's stupid that voice and data are so closely tied that this is even necessary.
     
  5. Mikegs thread starter macrumors regular

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    Aug 6, 2010
    #5
    @ Drag'nGT

    So you agree with me that there is no option to selectively using GSM for calls without also removing 3G data capabilities?
     
  6. bradl macrumors 68040

    bradl

    Joined:
    Jun 16, 2008
    #6
    There is. You turn off 3G, which reverts both your voice and data to EDGE/GPRS. All of this occurs using GSM. Think of this as GSM being the network that you are using, and EDGE/GPRS and 3G are the speeds that your voice and data will use on that GSM network. 3G will obviously be the faster of the two.

    BL.
     
  7. maturola macrumors 68040

    maturola

    Joined:
    Oct 29, 2007
    Location:
    Atlanta, GA
    #7
    You are correct, that is not possible. one of the advantages of of the third Generation standard was the ability to transmits voice and data on the same carrier signal (Voice on 3G is not longer a analog signal, it is transmitted as data, so to the network voice and data look the same). if you want to use GSM for Calls, it will forced the radio to transmit data on a separate carrier signal, so it needs a different modulation scheme and it cannot use 3G (for data only).

    Some devices accomplished this using multiple radios, they way Verizon is going to do it with LTE at the beginning.
     
  8. err404 macrumors 68020

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    Mar 4, 2007
    #8
    What model was your previous phone? I didn't think that this was possible due to the way cell towers register themselves to your handset.
     
  9. err404 macrumors 68020

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    Mar 4, 2007
    #9
    Verizon is a different story, since initially only CDMA will be used for voice and LTE for data.
     
  10. maturola macrumors 68040

    maturola

    Joined:
    Oct 29, 2007
    Location:
    Atlanta, GA
    #10
    Not sure what your point is, since that is what i said, they cannot do that with a single modulation, they need 2 devices to manage those tasks.
     
  11. Mikegs thread starter macrumors regular

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    Aug 6, 2010
    #11
    Previous phone was Nokia 5800. Choice was GSM or UMTS or both.
     
  12. Daveoc64 macrumors 601

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    Jan 16, 2008
    Location:
    Bristol, UK
    #12
    That's effectively the same as the choice provided by iOS.

    On a Nokia phone:

    When you choose GSM it'll only use the GSM (i.e. 2G networks) for both voice and data (at GPRS or EDGE speeds).

    When you choose UMTS it'll only use the UMTS (i.e. 3G network) for both voice and data.

    If you choose "Both" then the phone will use 3G when a good signal is available, switching back to 2G when there isn't a good 3G signal. The network may also tell your phone to switch to 2G.

    The iOS "Enable 3G" toggle when set to "On" is like the "Both" option on Nokia devices, and when the toggle is set to "Off", it is like the "GSM" option on Nokia devices.
     
  13. err404 macrumors 68020

    Joined:
    Mar 4, 2007
    #13
    My point is that it's not possible to maintain a simultaneous GSM and UMTS connection regardless of antenna configuration on the handset since the way the protocol is routed binds it to a single tower. Assuming that the OP's original phone was also on AT&T, he was likely mistaken as to its ability to selectively disable 3G for voice while leaving it enabled for data.

    Verizon is dealing with things a bit differently since the LTE radio is dedicated for data only (Voice can not be routed via the LTE connection). Essential they are proposing two separate cell phones in the same case.

    I'll concede that technically you could do this on ATT, but it would require two separate SIM cards/plans.
     
  14. maturola macrumors 68040

    maturola

    Joined:
    Oct 29, 2007
    Location:
    Atlanta, GA
    #14
    As i said,,just an example on how to accomplish something similar with multiple carrier signals, that is what i said.


    And for the records LTE can route voice just fine, Verizon just opt no going to the whole network shift at once, since there isn't really a handset that support is yet.
     

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