1. bengalih's Avatar
    If I buy an S4 from AT&T or Sprint can it be unlocked to run on all compatible networks?

    What about international? Do all versions have a SIM card slot that I can use for a country specific SIM card?

    Also, can anyone tell me if this is true of the S3 as well?

    Thanks!
    07-09-2013 12:01 PM
  2. ledfrog's Avatar
    If I buy an S4 from AT&T or Sprint can it be unlocked to run on all compatible networks?
    Only the S4 from AT&T can be unlocked and used on other GSM networks. Sprint and Verizon use CDMA so technically, the phone is "locked" to each of those services inherently. AT&T uses a real locking system that will keep the phone's IMEI number in their system for use ONLY on their network. They do this as part of the trade-off for you buying a $600-800 phone for only $200. As far as getting it unlocked, AT&T will do it for FREE as long as you are no longer on a contract OR sometimes if you're eligible for an upgrade. However, there are plenty of places online that will unlock your phone for a small fee if you don't want to wait for AT&T. The price is usually higher if the phone is a newer model.

    What about international? Do all versions have a SIM card slot that I can use for a country specific SIM card?
    Once an AT&T phone is unlocked, it can be used on T-Mobile (provided that the device works with HSPA+ or 3G) and any GSM carrier world-wide (which is just about every other country). These unlocked GSM phones can be used with international SIM cards just by swapping it out and turning it on. With a Verizon or Sprint phone, you can get the phone to work internationally, but you usually have to pay a service fee which will allow you to roam locally when abroad AND you have to have a device that is called a "world phone" to even be able to have it work. The advantage here is that you don't have to swap SIM cards...just get off the plane and your phone works...same number and all. I'm not sure the cost on this setup. The advantage with an unlocked GSM phone is that you can get off the plane, go to a local phone shop and buy a prepaid SIM card for the local costs and use it in your phone while you're travelling. The drawback is that you would have a new International phone number though.


    Also, can anyone tell me if this is true of the S3 as well?
    Everything above will apply to the GSM version of the S3 as well. You would want to check with Verizon and Sprint to ensure their versions of that phone will work internationally.
    07-09-2013 12:30 PM
  3. bengalih's Avatar
    ledfrog

    thanks for that info... what I am trying to ascertain is not just what is allowable by the carrier, but also what is actually possible given an unlock code and/or some phone hacking.

    Is the version of the S3/4 that Sprint gives me actually physically different than that of what AT&T gives me? If not, that would mean it is only being locked by the vendor and I would hope has some way around that.

    While we are at it...I am also looking for info on the RAZR series from Verizon...if you happen to have good knowledge of how those also function.

    thanks!
    07-09-2013 01:17 PM
  4. ledfrog's Avatar
    This should clarify things:

    • Unlocking an AT&T phone will only allow it to be used on any other compatible GSM network anywhere in the world. It does not change anything else about the phone. If you were able to buy an S3/S4 directly from Samsung with no phone plan or anything, this is how it would come..."unlocked." But you would pay the full retail price of $600+ for it. Currently, I don't think Samsung sells phones like this (at least in the U.S.)
    • A CDMA version of the phone (Sprint and Verizon) is physically different on the inside than a GSM model. These versions will not work on any other network other than a CDMA network which I think only exist in the U.S. these days. So no, there is no way around that because while there is no actual lock (like AT&T actually using software to lock your phone), it's considered "locked" just because you can't use a Verizon phone on Sprint or a Sprint phone on Verizon AND you can't use either of these phones on AT&T or any other GSM network.


    So while there are many things you can do to hack a Sprint phone in order to do some interesting things with it, the one thing you can't do is change what network it will work on. These are hardware limitations inside the phone. It would be like trying to make your car into an airplane...it's just not going to happen.

    What info were you looking for about the RAZR?
    07-09-2013 01:35 PM
  5. bengalih's Avatar
    Ok thanks...this was info that I couldn't definitively find anywhere. I understand that CDMA and GSM hardware is different, I just couldn't find any evidence that there were actually different models for the different carriers or whether there was one phone that could do both but was locked by the particular carrier.

    As far as the RAZR...I'll ask the questions in more detail here...but you can reply in this thread if you like (your choice):
    http://forums.androidcentral.com/dro...ml#post2908870

    Basically, I want to know the same for the RAZR. From what I have researched so far it appears that sometime since last year when the newest updates came from Verizon, that they unlocked GSM band on the phone. I can't find definitive info for this, but have read some posts that seemed to indicate this. People talking directly to Verizon are told that yes, it works for GSM...but only on their network (meaning you pay for Verizon roaming) - and that you can't put a foreign SIM in it. Of course, I won't trust Verizon to advertise you can...but I'd like to know.

    Additionally, if you can recommend any current phones that I will have the ability to use foreign sims in? It sounds like you are saying any AT&T phone unlocked will do it - but AT&T is currently my last choice of carrier and I'm hoping to get subsidized rates. So preferably a Verizon or Sprint phone that has both CDMA/GSM hardware in it and can be unlocked for a little elbow grease or a few bucks.

    thanks!
    07-09-2013 02:24 PM
  6. ledfrog's Avatar
    Here's what I found. Verizon has a Global Phone program that has devices that support dual-band GSM, quad-band GSM, UTMS and CDMA. You can get all that info here: Global Services - Verizon Wireless and a full list of devices here: Set Your Location

    So according to that list, the following RAZRs are Global ready:
    • Droid RAZR HD
    • Droid RAZR M
    • Droid RAZR MAXX HD
    07-09-2013 03:36 PM
  7. bengalih's Avatar
    Yeah - I saw that as well...it however isn't really definitive if you can use a foreign SIM in them or if they can simply be enabled by Verizon to work in foreign countries.
    I don't want to be beholden to Verizon's service out of the country.

    OK - so I just called the number listed on the Verizon Global Program website.

    They claim that *all* of those phones listed as Global Ready can have foreign SIMs inserted in them. Also, according to their site the RAZR M is also a GSM phone (which Wikipedia says its not).
    I need to go double check on Motorola's site to confirm which is the case.

    She did say some of them initially didn't support that - but with software updates they all now do.

    She stopped short of definitely saying that once I was out of contract I could use it on AT&T's GSM network...but implied that people do it.
    07-09-2013 03:52 PM
  8. ledfrog's Avatar
    Oh ok I understand exactly what you're saying now. I don't really know how it works with Verizon as far as SIM swapping, but if they say it works, then I would trust what they say. Plus, to me a SIM is a SIM and if the phone has one installed, then it should be no problem. Also, as I mentioned before, there are no "real" locks on a Verizon phone because Verizon knows that you can't take that phone to just any service. But the real question is whether that SIM card/port is locked to Verizon...that answer I do not have. I'm guessing based on what you said Verizon told you, it's NOT locked...otherwise you wouldn't be able to drop a foreign SIM card in there. This is very interesting to say the least!
    07-09-2013 04:15 PM
  9. Misty2016's Avatar
    I just want to know if there is a network compatible with Sprint? I have a paid off Galaxy S4 and I want to know if I leave them can I still use my phone.
    08-16-2016 08:49 AM

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