Roaming with T-Mobile'D iPhone

Discussion in 'iPhone Tips, Help and Troubleshooting' started by Tallest Skil, Aug 26, 2007.

  1. Tallest Skil macrumors P6

    Tallest Skil

    Joined:
    Aug 13, 2006
    Location:
    1 Geostationary Tower Plaza
    #1
    So, now that it's virtually been done, I have a question: Will the iPhone work on T-Mobile's 850 Mhz network? I'm roaming by default with AT&T (don't want them anyway...), and with T-Mobile I'm in their extended coverage area. I just want to know if even attempting to get service on my iPhone anywhere near me is possible. Thanks.

    Oh, and why can't the iPhone be used with Centennial? Not a SIM user?
     
  2. unity macrumors 6502a

    Joined:
    Sep 30, 2005
    Location:
    Green Bay, WI
    #2
    If you crack it, yes it will work. You mentioned you are off network? If so, like all carriers, after two months you *may* get bumped if you have a lot of usage since you violate the terms of service by exceeding more than 40% (I think) of your monthly service plan.

    And who the heck is Centennial? I assume a provider, they have to be a GSM network for the phone to work.
     
  3. Tallest Skil thread starter macrumors P6

    Tallest Skil

    Joined:
    Aug 13, 2006
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    #3
    What do you mean 'Who is Centennial?'?! Well, maybe they're not as nationwide as they say... Here: http://www.centennialwireless.com And yes, they're GSM, but I've found nothing about their use of SIM cards; although, I get the feeling there's a 99% chance that they'd have to use them to be GSM, but I know nothing about phone providers. So... T-Mobile would kick us after two months because we live somewhere. They don't charge more for roaming in their 850 Mhz range, but they'd kick us, eh? Seems to me that they should just include it in their coverage area if they're not going to charge more. Anyway, Centennial isn't roaming here, but again, no mention of SIMs. This may just be stupidity on my part, but I'd like to know if I can get a kick-awesome deal through them.

    Thanks,
    Skil
     
  4. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #4
    If Centennial uses GSM (sorry, I have no idea who they are either), then yes, they use SIM cards.

    The iPhone is quad band, meaning it operates on essentially all the GSM frequencies used everywhere in the world. This means that, assuming the provider allows the phone onto the network (in principle, phones can also be locked off of networks, but this is very rare), then yes, it will work for voice. If Centennial has an EDGE network, it will work for data services as well.

    As far as the getting kicked off part, the idea is that when you roam, there is a differential cost to your provider. They are paying for your access to that other network that you're roaming onto. The reason they don't charge you is that they find it easier and more appealing to customers to just average the costs out. The reason they kick out excessive roamers is because they don't fit the cost model. If you're concerned about being kicked out, though, and you're almost always outside of the T-Mobile network, you should definitely ask first. Do you even know that T-Mobile is willing to give you an account registered to your home address, if that address is outside their coverage area?


    P.S. this is your nationwide service provider (the states colored blue)

    [​IMG]

    And not very much of those states. For instance, the Detroit Metro is not covered in Michigan....
     
  5. plumbingandtech macrumors 68000

    Joined:
    Jun 20, 2007
    #5
    Sorry. Never heard of them either...

    But thanks for the link.

    Not very nationwide according to the map above though...
     
  6. Tallest Skil thread starter macrumors P6

    Tallest Skil

    Joined:
    Aug 13, 2006
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    #6
    When you say mine, do you mean Centennial? Hey, I use Verizon right now. I'm just weighing my options now that we're closer than ever to unlocking. Centennial's the only GSM provider that has non-roaming coverage where I live (Indiana). Hmm... so, if that's a map of all of Centennial's coverage, there's no wonder why you've never heard of it, unity. I just assumed it was nationwide since I see commercials all the time and their concept is "Blue Nation". Whatever. Hey, their website has Kentucky, Illinois, and Wisconsin in their coverage maps at least, too. :p Anyway, that's a relief. We'll probably go with Centennial then, since their family plan kicks ours' butt. I'll just tell them that I already have a phone that I want to use. "Oh, it's okay, I have a phone already." "What kind?" "I...'m not at liberty to discuss that..." ;)

    Epic thanks to you, mrkrishnan.
     
  7. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #7
    I looked some more at the Centennial website... be really careful with this BlueWeb or whatever they call it... make sure it isn't limited only to using WAP sites or something like that. They do seem to offer at least one smartphone (from HTC, I think), so you never know. But make sure you don't suddenly end up with a crippled iPhone because you have little/no data access capabilities! :( Unless you're prepared for that in advance.
     
  8. Tallest Skil thread starter macrumors P6

    Tallest Skil

    Joined:
    Aug 13, 2006
    Location:
    1 Geostationary Tower Plaza
    #8
    Hey, I'm fine with that. I'll just use Wi-Fi; faster anyway. I just wonder if the iPhone will recognize and try to use the data service; in which case, I wonder if I can turn it off. I don't want to waste money on a data plan or be charged for data I didn't want to use.
     
  9. GelleCC macrumors regular

    GelleCC

    Joined:
    Jul 13, 2008
    Location:
    Seattle, WA
    #9
    I"m just curious here, and this may be a stupid question, but I think I already have an answer but thought I'd ask since you seem to know what you're talking about...and I don't. lol If the iphone is quadband and can pick up almost any GSM frequency, then why cant the iphone run on tmobiles 3g in the USA? I know that tmo's 3g is on a different frequency than at&t's but if it's quadband, shouldn't it be able to pick up the 1900 mhz or whatever freq it is? Or does the quadband mean strictly cell service and not data service? Thanks.
     
  10. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #10
    Exactly -- in this context, the quadband refers to the GSM call/voice modem operating on four bands (850, 900, 1800, 1900). I believe the EDGE modem operates on these four bands also. The 3G modem supports UMTS/HSPA on three bands -- 850, 1900, and 2100 MHz, and HSPA at 7.2mbps on those bands on the 3GS.

    Now the confusing part is this: the way UMTS/HSPA 3G works, each device uses two frequencies -- one for uploading and one for downloading. The device has to be able to use both bands on a network to work in 3G -- they work as a matching pair. The matching pair must be supported for the function to work. If you look at this link:

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

    I believe the iPhone supports bands I, II, and V; T-Mobile uses IV.
     

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