GSM Frequencies

[tazman556]

Does ATT support GSM 900 and 1800 MHz frequencies?

I'm trying to get a GSM 2G alarm system set up and don't show any bars at all, no matter where I place the main unit. I put the SIM in my GoPhone as a test. That SIM works fine in my GoPhone, 5 bars too.

The other possibility is obvious if the frequencies are OK.

[tazman556]

Also, this system is 2G only.

[julywashere · Accepted solution]

Hi tazman,

AT&T uses different frequencies with different technologies. In some areas, they may not have a license to use both frequencies and use one exclusively. 

For GSM, they use 850 MHz and 1900 MHz. 
For HSPA+, they use 850 MHz (Band V) and 1900  MHz (Band II)
For LTE, they use 700 MHz (Band XVII) and some 1700 MHz (Band IV)

In your case, you'd be concerned with their GSM network. Which does not support the 900 Mhz frequency but does support the 1900 MHz band.

[dmapr · Accepted solution]

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@tazman556 wrote:

Does ATT support GSM 900 and 1800 MHz frequencies?

I'm trying to get a GSM 2G alarm system set up and don't show any bars at all, no matter where I place the main unit. I put the SIM in my GoPhone as a test. That SIM works fine in my GoPhone, 5 bars too.

The other possibility is obvious if the frequencies are OK.

---

Neither 900 nor 1800MHz frequencies are used in the US by any of the GSM operators. As

@julywashere explained, US operators are on 850 and 1900MHz frequencies.

[sribasu]

Hi,

I'm planning to buy Galaxy Note 3 globally unlocked version. In the product description I've seen following line:

• 3G: HSDPA 850 / 900 / 1900 / 2100

Does this mean that it will work fine with AT&T 3G?

[dmapr]

---

@sribasu wrote:

Hi,

I'm planning to buy Galaxy Note 3 globally unlocked version. In the product description I've seen following line:

• 3G: HSDPA 850 / 900 / 1900 / 2100

Does this mean that it will work fine with AT&T 3G?

---

Yes, that means it'll work on the HSPA+ network. It may not work on the LTE network.

[jzforty]

Hi,

I am looking to buy an unlocked modem like this, but not sure if it works in ATT network. It is unlock. It does support 850/1900mhz, but the spec said these frequencies are only for GSM and GPRS.

Vodafone K5150 (also K5150H) is a new 4G LTE Cat4 USB Stick from HUAWEI to support maximum download speed to 150Mbps and upload speed to 50Mbps. The HUAWEI K5150 supports LTE band 1, band 3, band 7 and band 20(800/1800/2100/2600MHz). Like its predecessor HUAWEI K5005, the unlocked K5150 Vodafone internet stick could also support 3G UMTS/DC-HSPA+ & 2G GRPS/GSM network.

Specifications:
* 4G LTE FDD Band 1/3/7/20: 800/1800/2100/2600MHz
* 3G DC-HSPA+/UMTS/WCDMA 900/2100MHz
* GSM/GPRS 850/900/1800/1900MHz

Thanks,

Justin

[dmapr]

---

@jzforty wrote:

Hi,

I am looking to buy an unlocked modem like this, but not sure if it works in ATT network. It is unlock. It does support 850/1900mhz, but the spec said these frequencies are only for GSM and GPRS.

Vodafone K5150 (also K5150H) is a new 4G LTE Cat4 USB Stick from HUAWEI to support maximum download speed to 150Mbps and upload speed to 50Mbps. The HUAWEI K5150 supports LTE band 1, band 3, band 7 and band 20(800/1800/2100/2600MHz). Like its predecessor HUAWEI K5005, the unlocked K5150 Vodafone internet stick could also support 3G UMTS/DC-HSPA+ & 2G GRPS/GSM network.

Specifications:
* 4G LTE FDD Band 1/3/7/20: 800/1800/2100/2600MHz
* 3G DC-HSPA+/UMTS/WCDMA 900/2100MHz
* GSM/GPRS 850/900/1800/1900MHz

Thanks,

Justin

---

Justin,

this modem will only work on AT&T in 2G (GPRS/EDGE) model. It does not have the necessary AT&T bands on either 3G or 4G radio. In order to fully function on A&T LTE network, your modem needs to support the following frequencies:

2G: 850/1900MHz

3G: 850/1900MHz

4G: Bands 2,4,5,17 (1900,1700,850,700MHZ)

[adidaskid808]

Justin,
 This Asian,Australia and EU phone can only work in 2G & maybe in some area of USA with AT&T coverage.
3G and 4G will not work!!! DO NOT waste your money!!!!!
 

[ItsStavBro]

So i have a phone that i got from a friend that i believe he may have gotten from china.  It is a lenovo and says the bandwiths are 850/900/1800/1900 mhz and 850/2100 mhz.  Will this work with AT&Ts 4G service as well as 3G.  Im planning to switch to them.

[adidaskid808]

As my post before,most cell phones you can buy in Mainland China are mostly for their local market.
This Lenovo famous Brand name phone will work on 2G GSM all over the world .
That's why in Mainland China they called it "WORLD/INTERNATION PHONE "
3G you may get limited coverage or none.

4G?? No way.

[hazardsoldier]

So I am a bit confused.  I live in Los Angeles, California. I am trying to find/purchase a LG G3, unlocked so that I can purchase a SIM card to use with Cricket Wireless which uses the AT&T network. The problem is that I see two different models, the D855 and the D850.  It says that the D855 is the international model with modes: GSM 850/900/1800/1900

                                                                       UMTS 850/900/1900/2100

                                                                       LTE     800/900/1800/2100/2600

The D850 has modes:  GSM 850/900/1800/1900

                                      UMTS 850/900/1900/2100

                                      LTE 700/850/1700/1900/2100

So which one is the one I should purchase that will work with Cricket giving me 4G LTE? I don't want to get the wrong one that will only give me 3G data. Any help will be greatly appreciated!!

[adidaskid808]

 Good question about this LG G3 phone.
I got lots of friends living in LA ,a few have a LG G3

and they all seem to tell me the same thing with AT&T .
(And if Cricket use the same Band as AT&T.)
Both phone will work on 2G(GSM) & 3G(UMTS)  and (3G+ (H++)= 4G in North America.
And lots of time ,the phone can only work on 4G.
Because both model of LG G3  got one LTE band missing for AT&T.
so, it is very much depends on area you're in.
And sometime LTE traffic are too heavy in LA,your speed will get drop down to 4G.

[hazardsoldier]

Okay...so just to clarify. This phone IS capable of having LTE coverage in
LA?

[adidaskid808]

It is capable to have AT&T LTE service.
Both LG G3  D850 and D855 .
But as my reply early.Both phones got some LTE bands missing for AT&T.
So, it is very much depends on which area of LA and where you using your phone.
But I will go for D850 ,since D855 are more for Asia and EU.

This is mainly from the data you give me.But last year 2014 July,I test out both phones D850 & D855 with AT&T Sim card,Both are on the $60 unlimited plan. In area of Jefferson,Koreatown,Chinatown & Santa Monica ,they mostly seem to like working on 4G most of the time