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  1. Xavier85's Avatar
    So I bought a z10 for my wife since the bold 9900 she's using (which was my 9900 I got when it first came out) is dying, keyboard buttons are all giving out. Anyways, the one I bought was off of Amazon, and since I'm an avid Crackberry user, I knew to make sure it was a STL100-3 and RFK121LW model just like mine, so no way it wouldn't have worked on T-Mobile USA.

    My question is this, I see that the only difference between the RFK121LW and RFF91LW is a missing radio frequency, had it been the RFF91LW I purchased and tried to use on T-mobile USA, what/would have been the difference due to the missing band? Would it still have had LTE?

    I just don't know about cellular bands, so I figured I would ask my Crackberry brethren. Any thoughts? Thanks.
    CeCoQ likes this.
    01-13-14 08:25 AM
  2. CeCoQ's Avatar
    The two models you listed, RFK121LW and RFF91LW, have the same LTE bands (700, 850, 1700, 1900), so both would have LTE.

    As you mentioned the only difference is that the RFK121LW has one extra HSPA+ band, which is the 1700 band.
    RFK121LW 800/850, 1700, 1900, 2100
    RFF91LW 800/850, 1900, 2100
    So If you bought the RFK121LW, you have the "better" phone, just because of the extra band, and it is needed for T-Mobile, not for AT&T. And if your RFK121LW is unlocked it will also work on AT&T 4G and LTE network.

    With the RFF91LW (1700MHz is not present) on T-Mobile, you will not be receiving signal if your phone is in an HSPA+ area on 1700Mhz.
    (T-Mobile operates HSPA+ on 1700/2100 and 1900)


    ..... and AT&T operates on 850 and 1900, so now you see why the RFF91LW would work well here and also the RFK121LW


    Hope this helps.



    So I bought a z10 for my wife since the bold 9900 she's using (which was my 9900 I got when it first came out) is dying, keyboard buttons are all giving out. Anyways, the one I bought was off of Amazon, and since I'm an avid Crackberry user, I knew to make sure it was a STL100-3 and RFK121LW model just like mine, so no way it wouldn't have worked on T-Mobile USA.

    My question is this, I see that the only difference between the RFK121LW and RFF91LW is a missing radio frequency, had it been the RFF91LW I purchased and tried to use on T-mobile USA, what/would have been the difference due to the missing band? Would it still have had LTE?

    I just don't know about cellular bands, so I figured I would ask my Crackberry brethren. Any thoughts? Thanks.
    01-13-14 08:50 AM
  3. Xavier85's Avatar
    Thanks, that helps. Luckily I got the right one anyways, but it's good to know the differences.
    CeCoQ likes this.
    01-13-14 08:57 AM
  4. heading4tomorrow's Avatar
    Thanks for the above info, any idea about which one AT&T is selling?
    I know both models have 850 and 1900 3G bands, and both models have same LTE bands, ideally both would work with both networks, but I am curious if they sell the same RFK or not?
    01-27-14 12:00 AM
  5. modifier's Avatar
    I own both an unlocked 91LW and unlocked 121LW and both work identically on Tmo across 2G, 3G/4G, and 4G LTE, including the elusive 1700 MHz 3G. I've tested on known 1700 MHz 3G towers and confirmed using the "Radio" app in BBW.

    Tmo sells the 121LW variant and AT&T sells the 91LW variant, both of which are locked and branded if buying through them. If you buy one direct from BlackBerry then you get an unlocked and unbranded 121LW.

    Posted via CB10
    heading4tomorrow and lift like this.
    01-27-14 12:52 AM
  6. heading4tomorrow's Avatar
    I own both an unlocked 91LW and unlocked 121LW and both work identically on Tmo across 2G, 3G/4G, and 4G LTE, including the elusive 1700 MHz 3G. I've tested on known 1700 MHz 3G towers and confirmed using the "Radio" app in BBW.

    Tmo sells the 121LW variant and AT&T sells the 91LW variant, both of which are locked and branded if buying through them. If you buy one direct from BlackBerry then you get an unlocked and unbranded 121LW.

    Posted via CB10
    Awesome, T-Mo once again destroys AT&T in BB friendly support... And this is coming from a AT&T customer of 7 years (before that 7 years with T-Mo)
    01-27-14 01:05 AM
  7. Saul Sanchez3's Avatar
    I am looking for a STL100-3 and RFK121LW model, preferably white. My question is, buying from Amazon, how did you make sure it was that model?

    P.S. First time crackberry user; I'm sure I'm doing this wrong and do apologize. I just really would like to know this. Thank you.
    06-02-14 08:55 PM
  8. Saul Sanchez3's Avatar
    You said "Tmo sells the 121LW variant." I've looked on their sight and found no Z10. Where can I get the 121LW from T-Mobile? I ask because I don't know how to guarantee that I will get the 121LW model, which I need. Thank you.
    06-02-14 08:58 PM
  9. lift's Avatar
    You said "Tmo sells the 121LW variant." I've looked on their sight and found no Z10. Where can I get the 121LW from T-Mobile? I ask because I don't know how to guarantee that I will get the 121LW model, which I need. Thank you.
    If you want to be sure you get the STL100-3 RFK121LW just buy a T-Mobile branded Z10 from anywhere you find one at a good price. As was already mentioned, If you buy from BlackBerry directly from their online USA store, you will get the STL100-3 RFK121LW.
    06-02-14 09:50 PM
  10. Xilus79's Avatar
    You said "Tmo sells the 121LW variant." I've looked on their sight and found no Z10. Where can I get the 121LW from T-Mobile? I ask because I don't know how to guarantee that I will get the 121LW model, which I need. Thank you.
    I thought BlackBerry cut ties with T-Mobile. So maybe that's why you're not seeing it in the website anymore.

    Like the previous poster suggested, any T-Mobile branded Z10 would be the 121LW variant and would work on the T-Mobile network.

    Posted via CB10
    06-02-14 10:05 PM
  11. scrannel's Avatar
    Try calling T-Mo, they may admit they have a few.
    06-02-14 11:38 PM
  12. robroper's Avatar
    Use promo code BLACKBERRY1 at checkout. Don't know how long the promotion will last, but this is the best way to buy the Z10 and get the RFK121LW at a GREAT price. It is fully 'unlocked' and is the full quad-band model for best T-Mobile performance. Works on AT&T, too. .
    Last edited by robroper; 06-04-14 at 08:10 AM. Reason: Missed an important detail.
    06-04-14 08:08 AM
  13. lift's Avatar
    Use promo code BLACKBERRY1 at checkout. Don't know how long the promotion will last, but this is the best way to buy the Z10 and get the RFK121LW at a GREAT price. It is fully 'unlocked' and is the full quad-band model for best T-Mobile performance. Works on AT&T, too. .
    True! If that code doesn't work us promo code "SAVE100BB142" if you are in the USA.
    06-04-14 10:32 PM
  14. heading4tomorrow's Avatar
    True! If that code doesn't work us promo code "SAVE100BB142" if you are in the USA.
    But.. what is the model they are shipping?
    The reports state one model but how can you confirm before buying? It seems a bit sketchy.. They can just ship a different model since they don't state it at order screen.
    06-06-14 02:14 PM
  15. Xilus79's Avatar
    But.. what is the model they are shipping?
    The reports state one model but how can you confirm before buying? It seems a bit sketchy.. They can just ship a different model since they don't state it at order screen.
    Shop BlackBerry will only ship the STL100-4 variant bc this model pretty much works on all carriers. They just had other variants tailored to the specific needs in each respective country, and correct me if I'm wrong, but it might also have to do with the cost of an additional radio needed to connect to certain frequencies.

    Posted via CB10
    06-06-14 06:44 PM
  16. redrabbt's Avatar
    But.. what is the model they are shipping?
    The reports state one model but how can you confirm before buying? It seems a bit sketchy.. They can just ship a different model since they don't state it at order screen.
    Here's the one I got from SBB last week.

    Radio differences in RFK121LW vs RFF91LW, how will both work on T-mobile USA?-img_20140606_220740-2-.jpg

    Posted via CB10
    06-06-14 09:20 PM
  17. scrannel's Avatar
    Shop BlackBerry will only ship the STL100-4 variant bc this model pretty much works on all carriers. They just had other variants tailored to the specific needs in each respective country, and correct me if I'm wrong, but it might also have to do with the cost of an additional radio needed to connect to certain frequencies.

    Posted via CB10
    Unlikely since the 100-4 is for a CDMA network (Verizon). It works badly on all other networks because of its extremely limit GSM "side". I believe they ship the 100-3 as has been posted because it works on T-Mo and at&t. Probably Canadian carriers as well.
    Xilus79 likes this.
    06-07-14 07:04 AM
  18. Xilus79's Avatar
    Unlikely since the 100-4 is for a CDMA network (Verizon). It works badly on all other networks because of its extremely limit GSM "side". I believe they ship the 100-3 as has been posted because it works on T-Mo and at&t. Probably Canadian carriers as well.
    Yeh sorry don't know what I was saying lol. It was confirmed it was STL100-3 (121LW) earlier in the post lol :/

    Posted via CB10
    06-07-14 10:42 AM
  19. scrannel's Avatar
    Cool. It can get a bit murky.
    06-07-14 11:36 AM

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