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CnCz

join:2013-06-08
Dunnellon, FL
Reviews:
·Dish Network

[Need Info] Need clarification on understanding frequency/network marketspeak

I'm looking at various 'direct from china' unlocked Android based smartphones. I'm having some difficulty matching what the marketers say re: frequencies/network types with the information I've been able to gather about various carriers.

This is a typical example of marketspeak specs:

Networking GSM/WCDMA
Frequency 2G: GSM850/900/1800/1900 3G: WCDMA 850/1900/2100
Data transfer GPRS/HSPA/EDGE


According to opensignal.com, I have cell towers from Sprint(1), Verizon(6) and AT&T (4). As best as I can determine from various sources, the 3 nearby carriers support:

AT&T
3G GSM 850, 1900
4G LTE 700, 1700/2100

Sprint
3G CDMA 850, 1900
4G WiMax 800, 1900
LTE 800, 1900

Verizon
3G CDMA 850, 1900
4G LTE 700, 1700/2100


We currently have two smartphones in the house. They are:

Samsung R720 Admire
2G CDMA 800, 1900
3G CDMA 800, 1900
MetroPCS

Motorola DROID Pro XT160
2G CDMA 800, 1900
GSM 850, 900, 1800, 1900
3G CDMA2000 1xEV-DO
HSDPA 850, 1900, 2100
Verizon


The phone specs are directly from manufacturer websites. The current carriers are as indicated.

While opensignal didn't indicate MetroPCS cell towers near me, I have reasonable voice service with them and {marginal} 1X only data service.

The Motorola phone has fairly reliable 3G service.

I don't understand how WCDMA relates to CDMA or CDMA2000. There is also no direct correspondence between HSPA and HDSPA. i.e. The real question is would the above mentioned marketspeak specs work with all 3 indicated 'nearby' carriers and possibly also MetroPCS.

As I read the above, I'm guessing that an unlocked Motorola Droid XT160 will work with all four carriers. An unlocked Samsung R720 Admire would only work with MetroPCS and Verizon. The 'marketspeak specs' phone will probably work with all the above carriers.

These notes are also pertinent:

• There is no available 4G service where I live so I'm not currently concerned about 4G capability.
• None of the unlocked phones I'm looking at currently work with 700, 800 or 1700 frequencies.
• All the phones I'm looking at include Wi-Fi 802.11 b/g or better. All are capable of using Wi-Fi based Skype if I'm in an available hotspot.

Am I interperting the marketspecs correctly. Can somebody explain the compatibility between CDMA, CDMA2000, WCDMA? What about HSPA versus HSDPA?

I'm thinking about buying a relatively inexpensive {less than $100} smartphone to check these issues out. If it goes well, I plan on investing in a much higher specced phone. I intend to use it both as a 'phone' and as a reasonably high powered portable computer I keep with me.

Thoughts, clarification, explanations and other comments accepted.

Thanks.



dib22

join:2002-01-27
Kansas City, MO

1 recommendation

said by CnCz:

Can somebody explain the compatibility between CDMA, CDMA2000, WCDMA? What about HSPA versus HSDPA?

CDMA/CDMA2000 is what Sprint, Verizon, US Cellular, MetroPCS use.

»en.wikipedia.org/wiki/CDMA2000

Most CDMA providers operate locked NETWORKS... that is they control the database of allowed serial numbers (ESN/MEID) on their networks. You can't put an unlocked device on these carriers, because the device is not what is locked... the network is what is locked.

MetroPCS and Cricket might be exceptions to this (I know Cricket does allow non cricket ESN/MEIDS on their networks if they are technically compatible).

GSM/HSPA/UMTS(WCDMA) is what AT&T and T-Mobile use.

»en.wikipedia.org/wiki/GSM

GSM providers usually are SIM card based...and they sell locked DEVICES. These locked devices only work with a SIM card from the provider that sold the phone.

The network authenticates and allows service based on the serial numbers on the SIM card. This means that you can use unlocked devices with them by placing a valid active SIM into the unlocked phone, as they are looking to the SIM's serial number to let you on the network (unlike the cdma providers who are looking at the phones serial number).

The specs you list are:
Networking GSM/WCDMA
Frequency 2G: GSM850/900/1800/1900 3G: WCDMA 850/1900/2100
Data transfer GPRS/HSPA/EDGE

That would work on AT&T or T-Mobile or MVNO's for those providers, that is you could take the SIM card from att or tmo and use the phone with those specs.

Verizon and sprint would not be compatible with that device, and even if that device did support the CDMA2000 standard, Verizon and sprint would not let the device on their network unless they sold it (locked network).

Have a good one!

CnCz

join:2013-06-08
Dunnellon, FL
Reviews:
·Dish Network

1 recommendation

said by dib22:

Most CDMA providers operate locked NETWORKS... that is they control the database of allowed serial numbers (ESN/MEID) on their networks. You can't put an unlocked device on these carriers, because the device is not what is locked... the network is what is locked.

MetroPCS and Cricket might be exceptions to this (I know Cricket does allow non cricket ESN/MEIDS on their networks if they are technically compatible).

GSM/HSPA/UMTS(WCDMA) is what AT&T and T-Mobile use.

This is the key information I didn't have! I hadn't understood that CDMA based networks are locked in that manner. Thank you very much!!

Now I know what questions to ask of each type of network provider. FWIW, most of the phones I've looked at are all GSM family based. I have seen a {very} few which explicitly list CDMA{2000}.

I will risk a low cost purchase and experiment with it to see what results I get.

Once again, thank you.


dib22

join:2002-01-27
Kansas City, MO

said by CnCz:

FWIW, most of the phones I've looked at are all GSM family based. I have seen a {very} few which explicitly list CDMA{2000}.

Yes there is a giant market for GSM devices since so many providers all over the world use(d) that standard, and due to the simple swap of a SIM card to activate them.

I saw a few neat CDMA2000 phones from korea and other countries over the years, but they were almost always on cricket due to the network lockout with sprint/verizon.

When you move into the LTE realm thing get a bit fuzzy... LTE is technically an offshoot of GSM so it also has SIM card based systems.

While sprint/verizon LTE devices almost always have a removable LTE sim card... it only applies to data, as the voice service is still on the CDMA2000 standard. They also call them UICC's instead of SIM cards when it is related to LTE just for reference


medbuyer

join:2003-11-20
kudos:4
reply to CnCz

MetroPCS just got bought by Tmobile.

I would purchase a phone that's compatible with Tmobile's frequency specially if you could afford a penta band phone like Tmobile's S4. It has all the bands Tmobile uses which you can also use on AT&T but don't mistake it's the same AT&T's S4 as their unit is only quad band which you can't bring over to Tmobile.

Buying a cheap phone from overseas where you will not get any local support here isn't the smart move to test out networks.

I did a lot of research before buying my Tmobile S4 and jump shipped to Tmobile coming from AT&T.

As an alternative, you can buy a used GSM phone from craigslist and or ebay just making sure that it it unlocked and contract free.



brg

join:2001-01-03
Chicago, IL
kudos:1
reply to CnCz

Here is one thing that I do not notice answered yet:

said by CnCz:

I don't understand how WCDMA relates to CDMA or CDMA2000.

Wideband CDMA (WCDMA) is a third-generation (3G) wireless standard for both voice and data, initially offering data speeds up to 384 Kbps. WCDMA was the 3G technology used in the US by AT&T and T-Mobile.

Confusingly, WCDMA is =not= compatible with the CDMA networks used by, for example, Verizon and Sprint. WCDMA is a 3G extension to GSM networks.

GSM = traditional voice and 2G data (what does AT&T call it -- "Edge?"), and WCDMA provides 3G speeds on those GSM networks.

HSDPA and HSPA+ are newer upgrades to WCDMA that offer much faster data speeds. HSDPA and HSPA+ do not replace WCDMA, but rather build on and enhance WCDMA. Any phone with HSDPA or HSPA+ also includes WCDMA by definition. AT&T and TMo market HSDPA and HSPA+ as "4G" NON-LTE, but it's really "3.5G"

WCDMA is also referred to as UMTS - the two terms are effectively interchangeable.

Most WCDMA phones include GSM as well, for backward compatibility.


DannyZ
Gentoo Fanboy
Premium
join:2003-01-29
Erie, PA

said by brg:

GSM = traditional voice and 2G data (what does AT&T call it -- "Edge?"), and WCDMA provides 3G speeds on those GSM networks.

GSM originally used circuit-switched transport for both voice and data, until GPRS (2.5G) brought packet data, which was then extended to EDGE (2.75G).
--
Out the 10BaseT, through the modem, down the co-ax, over the fiber, across the backhaul, past the edge router, off the network...nothing but net


djdanska
Rudie32
Premium,MVM
join:2001-04-21
San Diego, CA
kudos:4
reply to CnCz

The new metropcs plans a simply put are prepaid t-mobile plans. Even connect to the t-mobile network too.