Can someone explain US networks simply for me please?

Discussion in 'iPhone' started by Cx38, Jul 21, 2013.

  1. Cx38 macrumors member

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    #1
    Like you have all this about EDGE (we have this but on phones that are pre 3G) but what is the whole GSM, CDMA thing? The way your networks work just confuses me and when reading threads I just get lost >.< Thank you.
     
  2. Applejuiced macrumors Westmere

    Applejuiced

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  3. Cx38 thread starter macrumors member

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    #3
    And the 'Grandfathered' plans. Like I call my good old T-Mobile PAYG sim (£10 a month, unlimited texts, unlimited 3G and the £10 credit) my Grandad plan because its bordering six years and that plan hasn't existed for almost three.
     
  4. Demonface macrumors 6502a

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    #4
    GSM - ATT & T-Mobile
    CDMA - Verizon , MetroPcs , Sprint , Cricket ETC.
     
  5. Cx38 thread starter macrumors member

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    #5
    So what is the difference between GSM and CDMA?
     
  6. iDuel macrumors 6502a

    iDuel

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    #6
    The difference between CDMA and GSM networks is in the technology they use for voice and data. GSM networks are typically more common outside of the United States. GSM networks require a SIM card to be in the phone for it to work whereas CDMA networks do not require the presence of a SIM card (LTE aside) in order for the phone to receive service. GSM carriers in the U.S. include AT&T & T-Mobile. CDMA carriers are Verizon & Sprint.

    Here are some wikipedia articles which describe the technologies in detail:

    http://en.wikipedia.org/wiki/CDMA

    http://en.wikipedia.org/wiki/Gsm
     
  7. Cx38 thread starter macrumors member

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    #7
    Not sure if this has confused me even more or not but that you for the references, some bedtime reading for me :)
     
  8. Nermal Moderator

    Nermal

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    #8
    To further confuse the issue, a lot of people say "GSM" when they actually mean "UMTS" or "WCDMA". I'm not sure exactly how UMTS and WCDMA fit together (I think they complement each other).

    GSM is a 2G system that provides low data speeds and does not support simultaneous voice and data. WCDMA (3G) is often deployed alongside GSM and provides significantly faster speeds, plus simultaneous voice and data. In many areas GSM is still used as a fallback, but this is not a requirement of the technology (for example, Telecom here in NZ uses WCDMA exclusively).

    CDMA, more accurately called CDMA2000, sits somewhere between GSM and WCDMA in terms of technology. It provides faster data speeds than GSM and better call quality, but it's gradually being replaced with WCDMA or LTE throughout the world (for example it's no longer used in NZ or Australia, and I know that Canada started a transition but I don't know whether it's completed).

    Confused yet? :)
     
  9. Cx38 thread starter macrumors member

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    #9
    No, not at all. Surprisingly you made my brain 'ping'. We still have GSM in the UK but only for ancient/ultra basic phones. Seriously though, your post made sense :)

    ----------

    One question, what do you mean by voice and data?
     
  10. Daveoc64 macrumors 601

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    #10
    I don't see why you think that's the case.

    Millions of people will be using GSM every day with smartphones in the UK (iPhone included).

    Something like 45% of phones in the UK are 2G (GSM) only.
     
  11. Nermal Moderator

    Nermal

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    #11
    On a WCDMA network you can use the Internet while you're on a call. On GSM, you have to end your call before you can access data.
     
  12. Cx38 thread starter macrumors member

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    #12
    Really? See I've never had an android/ iPhone not on 3G. My Tocco Lite which is my back up runs GSM for Internet. Didn't know that was the case

    ----------

    Further enlightenment! I had no clue that you could do that :O Thanks :')
     
  13. Nermal Moderator

    Nermal

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    #13
    When I went to the UK in 2010 I was amazed at the sheer amount of GSM fallback. It seems that you guys have a long way to go...
     
  14. Cx38 thread starter macrumors member

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    #14
    2010 we had barely heard of 3G. Our LTE is only available in certain areas as they're still working on coverage.
     
  15. takeshi74, Jul 22, 2013
    Last edited: Jul 22, 2013

    takeshi74 macrumors 601

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    #15
    It really boils down to this: a consumer should select whatever network provides the coverage the consumer needs in the places that the consumer needs it most. They way the networks work isn't going to be relevant to most people. It's whether a given carrier will work or not for the individual that will matter.

    "GSM" and "CDMA" aren't necessarily used to refer to the current network tech in use but whether the carrier was historically GSM or CDMA.
     
  16. TheProFTW macrumors regular

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    #16
    Okay, so here's how it works:


    LTE: Used by all networks in the US, has fast speeds. Only some phones support voice on this, otherwize it goes back to 3g or 4g (By AT&T/T-Mobile's definition)


    GSM Networks: AT&T, T-Mobile. Used mostly everywhere
    GSM Technologies: GPRS, EDGE, UMTS, HSPA, HSPA+
    GPRS = 2G (The slowest of all)
    EDGE = 2G (or 2.5g, depending on who you ask)
    UMTS = 3G (Basic 3G technology, quite slow)
    HSPA = 3G (Revised 3G, fast enough. Most countries use this technology for 3G)
    HSPA+ = 3.5G/4G (Revised HSPA, way faster, almost LTE speeds, depending on the standard. It is advertised as 4G by AT&T and T-Mobile)

    CDMA Networks: Verizon, Sprint, Cricket, ETC. Useless standard IMO, doesn't use SIM cards (It does if the network uses LTE, which is based on GSM). Was used everywhere before GSM came in
    CDMA Technologies: CDMA, CDMA2000, EVDO
    CDMA: 2G
    CDMA2000: 3G (SLOW!!)
    EVDO: 3G (A little bit faster, but still slow. Max speed possible is 2mbps)
     
  17. KUguardgrl13 macrumors 68020

    KUguardgrl13

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    #17
    It really boils down to coverage in the areas you spend the most time in. Verizon and AT&T are normally the two best networks nationwide, although rural areas may have smaller carriers that work better in those areas. Sprint, T-Mobile, and the rest fall somewhere behind VZW and AT&T.

    GSM and CDMA are generally used to distinguish between old technologies that the networks used. Those names have stuck around since LTE coverage isn't universal yet. VZW and other CDMA phones fall back to those technologies when they can't get LTE, and the same with GSM for AT&T and others.

    The SIM card rule doesn't really apply anymore. Many VZW 3G phones had SIM cards.

    A modern distinction is that networks that were formerly GSM can support simultaneous talk and data. Former CDMA networks usually do not support that because they use both antennas to improve signal strength during calls.
     
  18. C DM macrumors Westmere

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    #18
    Actually GSM is the older one compared to CDMA. Overall CMDA is generally somewhat better as far as voice compared to GSM equivalent.

    CDMA2000 is usually known as 1x. For EVDO there are actually multiple revisions, like Rev. A, Rev. B, etc. that greatly increase the speeds, although not all of these pieces are implemented by most of US carriers.

    In a somewhat similar fashion the current LTE implementation isn't quite the actually originally envisioned LTE Advanced one which is now being strived for.
     
  19. Caesars macrumors regular

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    #19
    As someone who actually knows about most of the info in this thread, it's still a headache lol.
     

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