3G Revelation!

eureka

So I had to post my thoughts on 2 things that has been a big debate for a while now; The “fact” that 3G needs 2 frequencies to operate correctly and the “fact” that European 2100mhz is different that US 2100mhz.
I know that challenging this idea is going to get me a lot of emails about how wrong I am but hear me out..

1. 3G needs 2 frequencies to operate correctly

The majority accepted concept is that you need 2 frequencies for 3G to operate on a phone. You need 1 frequency for uploading information to the tower and 1 for downloading. For example, AT&T’s 2 frequencies they own are 850mhz/1900mhz and T-Mobile’s 2 frequencies are 1700mhz/2100mhz. We’ll use T-Mobile’s frequencies for this example.
So we are told that 1700mhz is what the phone needs to receive data from the tower and 2100mhz is what is needed to upload date back to the tower (both are needed to have a 3G connection on any device). But I don’t think that is entirely correct.
The reason is that there are plentty of T-Mobile devices that ONLY have the 1700mhz frequency and NO 2100mhz frequency and they GET 3G JUST FINE. (The Samsung Behold for example, but you can look up the frequencies on a few other TMobile 3G devices to see this same pattern). So how can that statement be correct?
I believe that maybe T-Mobile is using 1700mhz for up AND down at the moment (as there is only a benefit to use 1 frequency for up and 1 for down if you need the extra bandwidth on the tower, and with so few 3G customers I don’t believe it is necessary in the first place), and they own the 2100 but haven’t employeed it yet. It may even be on the towers but T-Mobile’s network is blocking access to it at the moment).
Anyone have any other explanation for how 2100mhz is missing from some 3G TMobile devices and in others (probably in preparation for the 2100 release) and they all get 3G? (If you comment please site a reliable source for your information, let’s all debunk this together!)

2. 2100mhz Europe is different than 2100mhz US (And that is why unlocked European phones with 2100 frequency built in won’t work on T-Mobile’s 2100 3G frequency).

So the next natural thing to challenge after the 2 frequency concept would be the fact that 2100mhz European phones don’t pick up 3G on T-Mobile’s 2100mhz because there is a difference in the frequencies. Well, what if it wasn’t because the frequencies were different but because T-Mobile wasn’t transmitting 2100 AT ALL?! And we are just assuming that our unlocked phones aren’t working because the frequency is different. What if the unlocked phones started to work down the road once T-Mobile releases their 2100mhz network?!

What are your thoughts?! And if you post a comment, please site reliable sources in your comment to prove your point for or against this idea.

UPDATE! – So I spoke to Haykuro on the phone today (he is the one responsible for porting the HTC Hero ROM to G1 users via XDA-Developers.com before the Hero was even announced be HTC) and I began to tell him this revelation I had. He immediately began to do what I have always done when asked about 3G frequencies, he told me that I needed 2 frequencies to get 3G on a network. Then I showed him the spec sheet for the Behold and a few other T-Mobile phones that ONLY have 1700mhz in them and said, “Then explain that”. He replied, “Uhh… that’s really interesting”.
Long story short, he is now working on a G1 Application to monitor the data packets being sent and received and (more importantly) over what frequencies they are being sent on. If we can see that the G1 is ONLY using 1700 and not 2100, well I think that’s all the proof we’d need, no?
Will post our results/the program on here as soon as he’s done 🙂

Any thoughts guys?!

55 responses to “3G Revelation!”

  1. […] projects their 3G network on 1700mhz (and we believe owns 2100 but isn’t using it yet, see 3G Revelation post for more details on that). Most European phone companies (where most unlocked phones are made […]

  2. Jordan says:

    Just a quick note. My friend’s mother works for t-mobile as an engineer in the Seattle area. I asked her about this and she said that T-Mobile is not yet using the 2100mhz band yet. 3G coverage is only on 1700mhz as of yesterday when I talked with her.

    • TheUnlockr says:

      Hello Jordan,

      Thanks that confirms what I thought and posted!
      Want to ask her something for everyone? Ask her if a 2100mhz capable phone from Europe will run on the 2100mhz frequency when T-Mobile uses it?

  3. Guest says:

    Just a quick note. My friend’s mother works for t-mobile as an engineer in the Seattle area. I asked her about this and she said that T-Mobile is not yet using the 2100mhz band yet. 3G coverage is only on 1700mhz as of yesterday when I talked with her.

    • David Cogen says:

      Hello Jordan,

      Thanks that confirms what I thought and posted!
      Want to ask her something for everyone? Ask her if a 2100mhz capable phone from Europe will run on the 2100mhz frequency when T-Mobile uses it?

  4. supertech says:

    thats because right now tmobile is downloading 3g and not uploading in 3g. as most people download stuff so 1700 is all that is needed. you can say the phones are not full 3G

  5. Guest says:

    thats because right now tmobile is downloading 3g and not uploading in 3g. as most people download stuff so 1700 is all that is needed. you can say the phones are not full 3G

  6. tcmc says:

    Thanks a lot guys. From my understanding, I CANNOT get 3G speed at 2100MHZ even if I buy a European cell which support 2100mhz simply because TMobile has not used it.

    • TheUnlockr says:

      Tcmc,

      Your welcome! That is our understanding at the moment. People have been arguing though that 2100mhz Euro is incompatible with 2100 US, but I think it might actually be compatible… What we do know is that 2100 isn’t being used by T-Mobile so we can’t test the theory either way.

  7. Guest says:

    Thanks a lot guys. From my understanding, I CANNOT get 3G speed at 2100MHZ even if I buy a European cell which support 2100mhz simply because TMobile has not used it.

    • David Cogen says:

      Tcmc,

      Your welcome! That is our understanding at the moment. People have been arguing though that 2100mhz Euro is incompatible with 2100 US, but I think it might actually be compatible… What we do know is that 2100 isn’t being used by T-Mobile so we can’t test the theory either way.

  8. Engineer says:

    This thread started off okay, but went way off track. Here is some information about the differnt 3G (UMTS/WCDMA) bands. AT&T is using Band II and V, T-Mobile USA is using Band IV, and Europe is using Band I (I think.)
    http://en.wikipedia.org/wiki/UMTS_frequency_bands
    I know this is wikipedia and should not be used for actual research, but in this case the information is okay.
    Again, the UE or phone will only transmit on the UL freq and recieve only the DL freq.
    If the phone doesn’t have the correct radio for the specific band, then it won’t work.

    • TheUnlockr says:

      Engineer,

      I understand how the frequencies are SUPPOSED to work. I to used to tell people all day long how 3G requires 2 frequencies blah blah just like you, BUT there is evidence against it. Not text book entries, actual evidence.
      Talk to Samsung about their Behold and Memoir. They do NOT have 2100mhz in them at all. So explain to me how a phone with only 1700mhz is getting 3G download speed and EDGE upload speed, besides what I wrote above. 1700mhz is in use 2100 is not. 1700mhz is being used for download and 2100mhz is not being used yet (probably because they don’t see a need for HSUPA just yet as most people in the States just care about download speed not upload).
      If you can explain how a phone with only 1700mhz is getting 3G down speeds according to your theory, let me know.

  9. Guest says:

    This thread started off okay, but went way off track. Here is some information about the differnt 3G (UMTS/WCDMA) bands. AT&T is using Band II and V, T-Mobile USA is using Band IV, and Europe is using Band I (I think.)
    http://en.wikipedia.org/wiki/UMTS_frequency_bands
    I know this is wikipedia and should not be used for actual research, but in this case the information is okay.
    Again, the UE or phone will only transmit on the UL freq and recieve only the DL freq.
    If the phone doesn’t have the correct radio for the specific band, then it won’t work.

    • David Cogen says:

      Engineer,

      I understand how the frequencies are SUPPOSED to work. I to used to tell people all day long how 3G requires 2 frequencies blah blah just like you, BUT there is evidence against it. Not text book entries, actual evidence.
      Talk to Samsung about their Behold and Memoir. They do NOT have 2100mhz in them at all. So explain to me how a phone with only 1700mhz is getting 3G download speed and EDGE upload speed, besides what I wrote above. 1700mhz is in use 2100 is not. 1700mhz is being used for download and 2100mhz is not being used yet (probably because they don’t see a need for HSUPA just yet as most people in the States just care about download speed not upload).
      If you can explain how a phone with only 1700mhz is getting 3G down speeds according to your theory, let me know.

  10. Engineer says:

    Unlockr,
    What I know is that it works like it is supposed to work. If a phone doesn’t have the UMTS band IV frequencies, then it won’t work on T-Mobile’s current 3G network. That means 1700/2100 are both required. Anyone who buys a phone without 1700/2100 (Band IV) should not expect it to work on T-Mobile in the future. Perhaps T-Mobile will use some of its PCS spectrum for UMTS similar to AT&T some time when GSM use dwindles.

    • TheUnlockr says:

      Engineer,

      Look, I’m not trying to argue with you. I TOO felt the same as you do for the longest time (it’s what we are taught). But NOONE can explain to me then how certain phones (like the Memoir and Behold 1) have ONLY 1700mhz built in and they get 3G download speeds? So until someone can explain that, my theory stands (even if it goes against conventional theory, as did a lot of theories until they were proven corrrect).
      I honestly just want to know, I don’t need to be proven right. If I’m wrong I’ll be the first to admit it, but since noone can explain 1700 alone to me…
      Help me try to figure this out, reach out to anyone you know and let me know what you find about it, let’s figure this out one way or the other 🙂

  11. the_sleeve says:

    Unlockr,

    Well I remember reading through our “3G Overview” page which pretty much explains to us how it works. That page said that T-Mobile uses 1700/2100 which we already know they own that spectrum. It also said that one is for uploading and the other is for downloading, again conventional thinking for 3G. Then it goes on to say that if a phone does not have both bands it will not pick up 3G.

    Now, I know that Samsung page tells us that the Memoir and Behold I do not have 2100 bands, the page I look at does show they do. However, the Gravity 2 shows in my sources as only having 1700. I guess I’ll do some more research next time I’m at work. Even my sources are contradictory 🙂

    • TheUnlockr says:

      The_Sleeve,

      See, I didn’t just make this stuff up! lol Let me know if you find anything? Know any tower engineers etc.? Anyone higher up that might know how a phone with only 1700mhz gets 3G?

  12. Engineer says:

    Unlockr,
    I am one of those “tower engineers”. Please take a look at the PDF version on the spec link you dropped. The phones have both 1700/2100. If they didn’t, they wouldn’t work and T-Mobile USA would not have sold them as a 3G capable phone. There isn’t any only using the 1700 and not 2100 for a later agenda. All T-Mobile 3G phones are using all of the AWS spectrum. There really isn’t any mystery on this one. The speeds will get faster as the HSPA upgrades are completed. With all that said, it is possible for a single data session to switch between 2G and 3G depending on network conditions. Also not all 3G phones are capable of HSPA+ data rates.

  13. Guest says:

    Unlockr,
    What I know is that it works like it is supposed to work. If a phone doesn’t have the UMTS band IV frequencies, then it won’t work on T-Mobile’s current 3G network. That means 1700/2100 are both required. Anyone who buys a phone without 1700/2100 (Band IV) should not expect it to work on T-Mobile in the future. Perhaps T-Mobile will use some of its PCS spectrum for UMTS similar to AT&T some time when GSM use dwindles.

    • David Cogen says:

      Engineer,

      Look, I’m not trying to argue with you. I TOO felt the same as you do for the longest time (it’s what we are taught). But NOONE can explain to me then how certain phones (like the Memoir and Behold 1) have ONLY 1700mhz built in and they get 3G download speeds? So until someone can explain that, my theory stands (even if it goes against conventional theory, as did a lot of theories until they were proven corrrect).
      I honestly just want to know, I don’t need to be proven right. If I’m wrong I’ll be the first to admit it, but since noone can explain 1700 alone to me…
      Help me try to figure this out, reach out to anyone you know and let me know what you find about it, let’s figure this out one way or the other 🙂

  14. Guest says:

    Unlockr,

    Well I remember reading through our “3G Overview” page which pretty much explains to us how it works. That page said that T-Mobile uses 1700/2100 which we already know they own that spectrum. It also said that one is for uploading and the other is for downloading, again conventional thinking for 3G. Then it goes on to say that if a phone does not have both bands it will not pick up 3G.

    Now, I know that Samsung page tells us that the Memoir and Behold I do not have 2100 bands, the page I look at does show they do. However, the Gravity 2 shows in my sources as only having 1700. I guess I’ll do some more research next time I’m at work. Even my sources are contradictory 🙂

    • David Cogen says:

      The_Sleeve,

      See, I didn’t just make this stuff up! lol Let me know if you find anything? Know any tower engineers etc.? Anyone higher up that might know how a phone with only 1700mhz gets 3G?

  15. Guest says:

    Unlockr,
    I am one of those “tower engineers”. Please take a look at the PDF version on the spec link you dropped. The phones have both 1700/2100. If they didn’t, they wouldn’t work and T-Mobile USA would not have sold them as a 3G capable phone. There isn’t any only using the 1700 and not 2100 for a later agenda. All T-Mobile 3G phones are using all of the AWS spectrum. There really isn’t any mystery on this one. The speeds will get faster as the HSPA upgrades are completed. With all that said, it is possible for a single data session to switch between 2G and 3G depending on network conditions. Also not all 3G phones are capable of HSPA+ data rates.

  16. Engineer says:

    Unlockr,
    I have tried to provide the needed information. It is clear to me that you are convinced that somehow the major carriers have invented a new way for 3G to work with half the spectrum. I guess we’ll have to just say you have stumbled on a miraculous discovery which will be unexplained for years to come. I’ll continue to read your articles for entertainment.
    Thanks.

  17. the_sleeve says:

    Unlockr,

    So I can try and ask our engineers or see if I can get a response from another group. I’ll send a request sometime tomorrow. Talking to our engineers though can only happen when they actually visit our building, so that’s more of a rareity.

  18. Engineer says:

    This is my last try to help clear this up. The “1700 Band” is made up of these frequency ranges (both of them) 1710-1755 and 2110-2155. These two ranges make up the AWS Band (aka 1700). Please refer to my previous Wikipedia link. To further complicate the subject, there are additional divisions into 5+5 and 10+10 MHz blocks. Different carriers could own different blocks in the same geographic area. This allows multiple AWS spectrum holders in the same market. Mystery solved?

  19. Guest says:

    Unlockr,
    I have tried to provide the needed information. It is clear to me that you are convinced that somehow the major carriers have invented a new way for 3G to work with half the spectrum. I guess we’ll have to just say you have stumbled on a miraculous discovery which will be unexplained for years to come. I’ll continue to read your articles for entertainment.
    Thanks.

  20. Guest says:

    Unlockr,

    So I can try and ask our engineers or see if I can get a response from another group. I’ll send a request sometime tomorrow. Talking to our engineers though can only happen when they actually visit our building, so that’s more of a rareity.

  21. Guest says:

    This is my last try to help clear this up. The “1700 Band” is made up of these frequency ranges (both of them) 1710-1755 and 2110-2155. These two ranges make up the AWS Band (aka 1700). Please refer to my previous Wikipedia link. To further complicate the subject, there are additional divisions into 5+5 and 10+10 MHz blocks. Different carriers could own different blocks in the same geographic area. This allows multiple AWS spectrum holders in the same market. Mystery solved?

  22. the_sleeve says:

    Engineer,

    So, in a way you’re confirming what we’ve been talking about. From what you just said about Band IV and re-referencing you wiki article that band contains 1710-1755 for UL and 2110-2155 for DL.

    I guess the only question left is if T-Mobile owns any Band I spectrum. Clearly, if they do it has not been employed yet which is why phones from Europe will not work with T-Mobile’s 3G.

    I believe we were seeing things differently because we were using “Band I” and “2100” band interchangeably (is that a word?) But now it all magically clicked with that last post, which in a way confirms the Unlockrs thoughts but with some clarification.

    T-Mobile only uses Band IV (which I now noticed you said earlier, my apologies)

  23. the_sleeve says:

    Forgot to add that I know according to the wiki page Band I is not deployed in the Americas at all, therefore phones that include that band are designed to work overseas for data as well (my assumption).

  24. the_sleeve says:

    Sorry it took me so long to realize you were both saying the same in different words 😀 haha

    • TheUnlockr says:

      The_Sleeve,

      Ya but he keeps saying that when a manufacturer puts 1700mhz listed on the spec sheet it also automatically means that 2100mhz is in the phone as well (because from his point of view and is common thought that it HAS TO for 3G to work). But this isn’t true, if you look at FCC documentation of these phones with 1700mhz only, they show the 1700 range but they do NOT show a 2100 range and they HAVE to on FCC documentation.
      So I guess him and I will just have to agree to disagree and wait until someone ACTUALLY proves one of us wrong lol Instead of the two of us repeating our selves over and over (he’s getting frustrated judging by his “I’ll continue to read your blog and be amuzed even though your wrong comment” lol

      Deal @Engineer? Agree to disagree until someone has real proof?

  25. Engineer says:

    Unlockr,
    I reckon I should appologize as I may have come across a little short. I sometimes forget that my industry lives in acronyms and technical details. Occasionally, it makes it difficult to communicate with normal people. (ask my wife) Looking back on the thread, I guess what was throwing me off was when you used “1700mhz” as I thought you were speaking to a specific frequency and not the 1710-1755/2110-2155 combined UL/DL frequencies (or UMTS Band IV / AWS). Uhh,kind of funny.
    Thanks for hosting a great site.

  26. Guest says:

    Engineer,

    So, in a way you’re confirming what we’ve been talking about. From what you just said about Band IV and re-referencing you wiki article that band contains 1710-1755 for UL and 2110-2155 for DL.

    I guess the only question left is if T-Mobile owns any Band I spectrum. Clearly, if they do it has not been employed yet which is why phones from Europe will not work with T-Mobile’s 3G.

    I believe we were seeing things differently because we were using “Band I” and “2100” band interchangeably (is that a word?) But now it all magically clicked with that last post, which in a way confirms the Unlockrs thoughts but with some clarification.

    T-Mobile only uses Band IV (which I now noticed you said earlier, my apologies)

  27. Guest says:

    Forgot to add that I know according to the wiki page Band I is not deployed in the Americas at all, therefore phones that include that band are designed to work overseas for data as well (my assumption).

  28. Engineer says:

    Unlockr,
    I think I can explain the FCC. The band IV phone only transmits between 1710MHz and 1755MHz as required by the FCC. The phone also has a receiver to catch the 2110MHz to 2155MHz the tower is transmitting. The FCC regulates the tower equipment also. The FCC is only concerned with the radiation source. Receivers do not generate interference, so they don’t go through FCC testing. It is very important that a transmitter only transmits the frequency it is designed for at the levels permitted by our laws.

  29. Guest says:

    Sorry it took me so long to realize you were both saying the same in different words 😀 haha

    • David Cogen says:

      The_Sleeve,

      Ya but he keeps saying that when a manufacturer puts 1700mhz listed on the spec sheet it also automatically means that 2100mhz is in the phone as well (because from his point of view and is common thought that it HAS TO for 3G to work). But this isn’t true, if you look at FCC documentation of these phones with 1700mhz only, they show the 1700 range but they do NOT show a 2100 range and they HAVE to on FCC documentation.
      So I guess him and I will just have to agree to disagree and wait until someone ACTUALLY proves one of us wrong lol Instead of the two of us repeating our selves over and over (he’s getting frustrated judging by his “I’ll continue to read your blog and be amuzed even though your wrong comment” lol

      Deal @Engineer? Agree to disagree until someone has real proof?

  30. Guest says:

    Unlockr,
    I reckon I should appologize as I may have come across a little short. I sometimes forget that my industry lives in acronyms and technical details. Occasionally, it makes it difficult to communicate with normal people. (ask my wife) Looking back on the thread, I guess what was throwing me off was when you used “1700mhz” as I thought you were speaking to a specific frequency and not the 1710-1755/2110-2155 combined UL/DL frequencies (or UMTS Band IV / AWS). Uhh,kind of funny.
    Thanks for hosting a great site.

  31. Guest says:

    Unlockr,
    I think I can explain the FCC. The band IV phone only transmits between 1710MHz and 1755MHz as required by the FCC. The phone also has a receiver to catch the 2110MHz to 2155MHz the tower is transmitting. The FCC regulates the tower equipment also. The FCC is only concerned with the radiation source. Receivers do not generate interference, so they don’t go through FCC testing. It is very important that a transmitter only transmits the frequency it is designed for at the levels permitted by our laws.

  32. the_sleeve says:

    so…my g1 is temporarily out of commission so ive been using my 3 year old samsung blackjack that i got from at&t with my tmo sim. interesting thing is for the last 15 minutes or so i had 3g which just now dropped bacl to edge. very interesting…

  33. Guest says:

    so…my g1 is temporarily out of commission so ive been using my 3 year old samsung blackjack that i got from at&t with my tmo sim. interesting thing is for the last 15 minutes or so i had 3g which just now dropped bacl to edge. very interesting…

  34. Killerpollox7 says:

    How did this end?

  35. Guest says:

    How did this end?

  36. Aestrada says:

    Well, thank you for the input.
     
    However, your data is a little off. Nokia is the GSM king. Since I travel between the USA and Europe a lot and have several, French cell phones, I did the 3G dance. As a background, I am an RF engineer and used to work in the cell industry. This is what I found.
     
    I use T-mobile here in the states. When Nokia came out with the N97  in mid 2009, my Orange French contract was up for renewal. I had the N95 that did not work with 3G here in the USA. The N97 has 3G. Cool. I had it unlocked and brought it home. No joy. It would only work on EDGE as your article mentions. The 3G specs for the N97 are:
     

    HSDPA 900 / 1900 / 2100     I was very sad. I did manage to speak to a T-mobile engineer a few days later. He explained that they use 1700 and 2100 MHz. He was right. I had edge with the N97 but no 3G.  A while later Nokia came out with a true, iPhone killer, the N900. On specs this is an amazing phone. I won’t comment on Nokia’s brain cramp by not developing an app. base with a real OS.  For 2G GSM 850 / 900 / 1800 / 1900For 3G HSDPA 900 / 1700 / 2100 You can see the full specs at http://www.gsmarena.com/nokia_n900-2917.php  This time all went well. The N900 works just fine and dandy. I get 3G with T-Mobile and 2G in weak signal areas. As with most smart cell phones, it eats battery life for breakfast, lunch and dinner. However, it works well.  So at least for T-Mobile, you need both 1700 and 2100MHz for 3G.  I will be buying for upgrading my N97 to the N8. It has some great features including a great 3G suite. HSDPA 850 / 900 / 1700 / 1900 / 2100  So that phone should cover 3G anywhere on the planet! So Nokia made a universal 3G phone. This is very cool. The only down side of buying the N8 in France is that the keyboard has a difference layout. 🙂 FYI the iPhone 4’s 3G specs are HSDPA 850 / 900 / 1900 / 2100 , which means it can’t work with T-Mobile.  The 4S’ 3G is
    HSDPA 850 / 900 / 1900 / 2100 CDMA2000 1xEV-DO  which means it also won’t 3G on T-mobile.  It is good to be an RF engineer at times! Anthony
      
      

  37. Guest says:

    Well, thank you for the input.
     
    However, your data is a little off. Nokia is the GSM king. Since I travel between the USA and Europe a lot and have several, French cell phones, I did the 3G dance. As a background, I am an RF engineer and used to work in the cell industry. This is what I found.
     
    I use T-mobile here in the states. When Nokia came out with the N97  in mid 2009, my Orange French contract was up for renewal. I had the N95 that did not work with 3G here in the USA. The N97 has 3G. Cool. I had it unlocked and brought it home. No joy. It would only work on EDGE as your article mentions. The 3G specs for the N97 are:
     

    HSDPA 900 / 1900 / 2100     I was very sad. I did manage to speak to a T-mobile engineer a few days later. He explained that they use 1700 and 2100 MHz. He was right. I had edge with the N97 but no 3G.  A while later Nokia came out with a true, iPhone killer, the N900. On specs this is an amazing phone. I won’t comment on Nokia’s brain cramp by not developing an app. base with a real OS.  For 2G GSM 850 / 900 / 1800 / 1900For 3G HSDPA 900 / 1700 / 2100 You can see the full specs at http://www.gsmarena.com/nokia_n900-2917.php  This time all went well. The N900 works just fine and dandy. I get 3G with T-Mobile and 2G in weak signal areas. As with most smart cell phones, it eats battery life for breakfast, lunch and dinner. However, it works well.  So at least for T-Mobile, you need both 1700 and 2100MHz for 3G.  I will be buying for upgrading my N97 to the N8. It has some great features including a great 3G suite. HSDPA 850 / 900 / 1700 / 1900 / 2100  So that phone should cover 3G anywhere on the planet! So Nokia made a universal 3G phone. This is very cool. The only down side of buying the N8 in France is that the keyboard has a difference layout. 🙂 FYI the iPhone 4’s 3G specs are HSDPA 850 / 900 / 1900 / 2100 , which means it can’t work with T-Mobile.  The 4S’ 3G is
    HSDPA 850 / 900 / 1900 / 2100 CDMA2000 1xEV-DO  which means it also won’t 3G on T-mobile.  It is good to be an RF engineer at times! Anthony
      
      

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