Develop Bugs

WCDMA Desire

I have a desire in Korea running on a WCDMA sim chip on the SK Telecom network. I'm currently in Canada for a while and would like to not have to use roaming. Is it possible to unlock this phone? Are there android 2.2 roms for this phone? If I do this will it disrupt my service with SKT at all? Korea does things a little differently.

I'd head over to the dev forum where you can find a load of unofficial Froyo ROMs.
You can unlock by either paying for an unlock code online and popping that in when using another SIM or flashing the radio which will require root if I'm correct.

Thanks. Whenever I see posts about the desire its always about gsm phones and my sim says its wcdma. Will these roms work?

WCMDA *is* GSM. More correctly WCDMA is a part of the technology used by most GSM networks to implement 3G.
Regard,
Dave

You're saying that CDMA is the same as GSM? Huh?

cliff_dangers said:
You're saying that CDMA is the same as GSM? Huh?
Click to expand...
Click to collapse
WCDMA and CDMA are not related and completley different.

Dude, you need to go and Google the difference between CDMA and WCDMA or 3G for everyone else out there. Your WCDMA phone is nothing special over the other phones out there
Sent from my HTC Desire using XDA App

WCDMA uses the same system as gsm (uses interchangeable sim cards) but is used on 3g networks running hsdpa because it was found that the old system (tdma) could not cope with the exponential growth of mobile phones and the fact they will consume more of the network's resources. All WCDMA phones are also equipped with old style gsm radio for when there's no 3g coverage. One worry about roaming to north America is that WCDMA uses different frequencies than the rest of the planet but for straightforward phoning and texting and edge you should fine since the 2g bit of the phone is quad band.
Source: cloudy memories from communications technology lessons, please correct me if wrong.
Sent from my HTC Desire using XDA App

huwwatkins said:
WCDMA and CDMA are not related and completley different.
Click to expand...
Click to collapse
Not exactly true! They are very closely related technologies, but the actual implementations are incompatible.
Regards,
Dave

[Q] Anyone know of an "all bands" 3g Android phone?

Given the fun and FUD surrounding the AT&T-Mobile merge, does anyone know of an Android phone that can play 3g on *anyone's* GSM network? I noticed that the crApple Ipuke 4 has 4 3g bands (presumably so they can have "One SKU to connect them all") Are there any Droids with that capability?

There are some phones listed as "Coming Soon" under the tmo site that have all bands. I'm not sure that any are available at this time.

tronmech said:
Given the fun and FUD surrounding the AT&T-Mobile merge, does anyone know of an Android phone that can play 3g on *anyone's* GSM network? I noticed that the crApple Ipuke 4 has 4 3g bands (presumably so they can have "One SKU to connect them all") Are there any Droids with that capability?
Click to expand...
Click to collapse
So far the only phone capable of ALL GSM Bands is Nokia N8. No Android or Windows or the Apple is capable of doing so as of now... iPhone doesn't support 1700...
AT&T might have such a phone in future if the merger ever happens... And man, that will be an awesome feeling to have a phone of my choice of OS and I don't have to bother being restricted with one career...
I am worried, if Canada will ever see that phone... :-(

The Samsung Vibrant has the 1900 band which works for AT&T (AT&T use 850,1900), so it may cover all area, but it works in NYC
Sent from my HTC Vision using XDA App

creativedevil said:
... And man, that will be an awesome feeling to have a phone of my choice of OS and I don't have to bother being restricted with one career...
(
Click to expand...
Click to collapse
Lol cell phone career giving you choice? Thats the best joke i have ever heard

Not sure what the original question is exactly, because GSM is really only one band around 900 Mhz. My understanding is this is normally used for EDGE, and 3G speeds / HSPA usually occurs only on the much higher frequencies.
And technically speaking, there is no GSM in the Americas, only in Eurasia. Here we have 850Mhz which should be referred to as CLR not GSM.
But if you're talking about Android phones that are 3G capable on both AWS frequencies (T-Mobile) and PCS (AT&T, Bell), check out the newly-announced LG G2X. Appears to have frequency bands for both, as well of course as CLR (Edge speeds).
The iPhone 4 does *NOT* have such a radio.
http://en.wikipedia.org/wiki/UMTS_frequency_bands

The N1 has you covered on most bands, but not quite all of them. By the time the merger goes through, though, there will probably be more and better options.

linkmaster_6 said:
Lol cell phone career giving you choice? Thats the best joke i have ever heard
Click to expand...
Click to collapse
Hahaha very funny, isn't it? Well, its not... cuz you obviously didn't get the point... Its not a choice given by career, its about the the contracts you have to go with... and if there ever is a phone which can support all the frequencies, it will give an option to switch between any GSM providers. Currently it is only possible with Nokia N8...

The G2x should support all popular bands.
Sent from my HTC Vision using XDA Premium App

Anomaly said:
The G2x should support all popular bands.
Sent from my HTC Vision using XDA Premium App
Click to expand...
Click to collapse
Unfortunately it doesn't for 3G connection.
http://www.gsmarena.com/t_mobile_g2x-3888.php

Galaxy Nexus GSM vs. CDMA

What's the differences between the two, if any?
I've been contemplating whether or not I should get the GSM version or CDMA. Are there any major differences between the two?
Sent from the future.

If you're on sprint, you kind of need to change to Verizon if you want the CDMA version. CDMA also has LTE aka true 4G, so speed will probably be better. VZW also has further reaching 3G coverage than AT&T, generally. On top of this, in my experience VZW's customer service is great, but everyone's mileage varies there.
The GSM version is not "official" for the US - you will have to pay full retail price on one ($600-ish) and sign up with tmobile or att to use it. No carrier subsidy.
Without further information about you, it's hard to say anything more.

I think the op was asking about the hardware spec. CDMA version has bigger battery and twice the storage space.

Does this mean that the Verizon version will not work on at&t? Or have slower speeds?

thanks. I wasn't referring to carrier information, though. I meant as far as hardware and software.
Did android 4.1 come with the Verizon version as promised?
Sent from the future.

SocialReject said:
thanks. I wasn't referring to carrier information, though. I meant as far as hardware and software.
Did android 4.1 come with the Verizon version as promised?
Sent from the future.
Click to expand...
Click to collapse
Verizon comes with 4.0.1 with a small update leading it to 4.0.2

ootz0rz said:
Does this mean that the Verizon version will not work on at&t? Or have slower speeds?
Click to expand...
Click to collapse
Yes, verizon version will not work on ATT.
In the US is very simple. Two types of radios: CDMA and GSM.
Verizon and Sprint use CDMA.
ATT and TMO use GSM.
The smaller carriers generally use either CDMA or GSM and piggy back off the larger carrier towers.
Hopefully android devices which have hardware and software capable of using both radios will arrive and it'll become less of an issue, but as of now, the galaxy nexus is either GSM or CDMA, but not both.
Hope that helps!

How about in the UK? Is there only one of these versions? And how do I find what version I have?

UK is gsm
Sent from my Galaxy Nexus using XDA App

ZPrimed said:
If you're on sprint, you kind of need to change to Verizon if you want the CDMA version. CDMA also has LTE aka true 4G, so speed will probably be better. VZW also has further reaching 3G coverage than AT&T, generally. On top of this, in my experience VZW's customer service is great, but everyone's mileage varies there.
The GSM version is not "official" for the US - you will have to pay full retail price on one ($600-ish) and sign up with tmobile or att to use it. No carrier subsidy.
Without further information about you, it's hard to say anything more.
Click to expand...
Click to collapse
LTE IS NOT true 4G.
There is no True 4G in the US.
Google the definition of 4G.

Hi everybody, I have a verizon Galaxy Nexus I understand it's a CDMA, is there any hardware differences between this and a GSM one? or is only software? will this device work on a GSM network if I flash a GSM Rom on it?
thanks for your help!

jhonyDroid said:
Hi everybody, I have a verizon Galaxy Nexus I understand it's a CDMA, is there any hardware differences between this and a GSM one? or is only software? will this device work on a GSM network if I flash a GSM Rom on it?
thanks for your help!
Click to expand...
Click to collapse
Don't even think about flashing a GSM rom on it.

mudferret said:
Don't even think about flashing a GSM rom on it.
Click to expand...
Click to collapse
thanks for your answer!
I thought it was some kind of adventurer try to mix roms but can you tell me what would happen by doing this? and, is there any way to get this CDMA phone work on a GSM network?
best regards!

jhonyDroid said:
Hi everybody, I have a verizon Galaxy Nexus I understand it's a CDMA, is there any hardware differences between this and a GSM one? or is only software? will this device work on a GSM network if I flash a GSM Rom on it?
thanks for your help!
Click to expand...
Click to collapse
Your CDMA version has a CDMA radio, a LTE radio, and antennas tuned to the correct LTE and CDMA frequencies used by Verizon.
The GSM version has a GSM radio with antenna turned to all common GSM frequencies.
The radios and antenna hardware are completely different in these versions and so by this fact the firmware (the software or flash able 'radio') is 100% different. Flashing the wrong one can cause all kinds of issues from not working until reflashing the correct ones yo bricking your radio (depending on how the firmware is flashed, size differences, etc.)
CDMA and GSM and LTE are all very different. LTE is based off GSM which is why you have a SIM card in LTE (though CDMA can have SIM cards if that is how the company set it up, which also is why without the SIM card you can't use your CDMA parts either).
Sent from my Galaxy Nexus using Tapatalk

jhonyDroid said:
I thought it was some kind of adventurer try to mix roms but can you tell me what would happen by doing this?
Click to expand...
Click to collapse
You will destroy your phone. It won't work ever again.
is there any way to get this CDMA phone work on a GSM network?
Click to expand...
Click to collapse
No. It's a hardware issue that can't be fixed with software.
---------- Post added at 10:21 AM ---------- Previous post was at 10:18 AM ----------
siberslug said:
LTE IS NOT true 4G.
Click to expand...
Click to collapse
Sure it is. Just like EDGE is "officially" 3G whenever carriers think it's in their marketing interest to say so. No one owns the term "3G" or "4G" so there's no such thing as "true" or "official". It is certainly marked performance advance over HSPA+, with real world LTE uplink speeds higher than HSPA downlink. It's at least as big of a jump from EDGE to UMTS (200kbps to 600kbps) was.
If you're referring to LTE Advanced, expect that technology to be labelled 5G when it hits the carriers. Why? Why the hell not? It's just a stupid marketing gimmick. Most consumers don't even know what the hell it means, with something like 70% of the population thinking that the iPhone 4/4S has 4G. Mo G's mo money.

Just to go along with what you are saying, the ITU changed it so that the current "4G" techs such as LTE, WIMAX, and HSPA+ are considered 4G.

Is my Galaxy Nexus SIM Unlocked?

Sorry, this question has probably been beat to death.
Is there a way I can verify if my Galaxy Nexus is SIM unlocked without putting in another SIM card? I don't have any other SIM available to test.
I got my phone from Telus with a new contract. The model shows GT-I9250TSDTLS and UPC is 629018066749.
I've read numerous reports that Galaxy Nexus in Canada comes factory unlocked. I was hoping I could verify before heading off on my trip, and making an unfortunate discovery.
Cheers,
jasphair

I'm not familiar with the Telus network as I do not live in Canada but it is my understanding that pretty much all carriers around the world lock the phone to their own network. This of course can be corrected by rooting then flashing 'universal' firmware on it.

jasphair said:
Sorry, this question has probably been beat to death.
Is there a way I can verify if my Galaxy Nexus is SIM unlocked without putting in another SIM card? I don't have any other SIM available to test.
I got my phone from Telus with a new contract. The model shows GT-I9250TSDTLS and UPC is 629018066749.
I've read numerous reports that Galaxy Nexus in Canada comes factory unlocked. I was hoping I could verify before heading off on my trip, and making an unfortunate discovery.
Cheers,
jasphair
Click to expand...
Click to collapse
I think it may be unlocked to Canadian carriers - I put a Rogers SIM in my Bell device and there was no request for a network unlock code - but when I went into fastboot mode the screen indicated my device was locked so I unlocked it using the Galaxy Nexus Toolkit. By the time I got drivers installed on a computer I was so frustrated that I chose the easy way.

you guys are confusing the locked bootloader to sim lock. they are two different things. unlocked bootloader allows you to flash roms, unlocked sim allows you to use sim cards from other carriers.
correct me of im wrong here but all north american gnex are sim unlocked. I've read here some people that have the UK gnex are carrier sim locked.

I'm pretty sure my Nexus is unlocked so yours should be too

All CDN carriers have unlocked GNs. A few countries abroad have SIM-locked GNs.

I don't know about Canada since i'm living in Norway, but if you get a new contract which subsidize the phone to make it a little cheaper they usually sim lock the phone.

Herman76 said:
I don't know about Canada since i'm living in Norway, but if you get a new contract which subsidize the phone to make it a little cheaper they usually sim lock the phone.
Click to expand...
Click to collapse
same here in canada, all the carriers that subsidize with contracts lock their phone. i've never gotten an sim unlocked phone from a carrier in canada until the galaxy nexus.

Yep, few of my friends and I have the GNex here in Vancouver BC. All Carrier unlocked, from North America (we swapped sims and tried each one).
Gotta love the unlocked, Pentaband goodness.

gundamboy said:
Yep, few of my friends and I have the GNex here in Vancouver BC. All Carrier unlocked, from North America (we swapped sims and tried each one).
Gotta love the unlocked, Pentaband goodness.
Click to expand...
Click to collapse
so the same galaxy nexus will work with the gsm carriers like rogers, telus, bell as well as mobilicity and wind?

neotekz said:
so the same galaxy nexus will work with the gsm carriers like rogers, telus, bell as well as mobilicity and wind?
Click to expand...
Click to collapse
Rogers is the only GSM carrier you have listed.
Every company in the list is an HSPA carrier.
Yes it will work on all of them.
Sent from my Galaxy Nexus using Tapatalk

cmstlist said:
All CDN carriers have unlocked GNs. A few countries abroad have SIM-locked GNs.
Click to expand...
Click to collapse
Even specifically the Telus Nexus signed on a three-year contract? Excuse me for my ignorance but I thought Telus, Rogers, Bell, etc. were only selling them unlocked if you bought them no contract. Thanks in advance.

cmstlist said:
Rogers is the only GSM carrier you have listed.
Every company in the list is an HSPA carrier.
Yes it will work on all of them.
Sent from my Galaxy Nexus using Tapatalk
Click to expand...
Click to collapse
You do realize that hspa is a gsm technology. all the providers are now on gsm tigers has just been on it longer.
Sent from my Galaxy Nexus

Matridom said:
You do realize that hspa is a gsm technology. all the providers are now on gsm tigers has just been on it longer.
Sent from my Galaxy Nexus
Click to expand...
Click to collapse
HSPA is a UMTS technology. UMTS networks are designed to be compatible for mode-switching with GSM, but they are fundamentally different technologies.
If you take a phone that has all GSM bands and no 3G support, and you insert a Bell or Telus SIM, you will get no signal. Therefore they are not GSM networks.

cmstlist said:
HSPA is a UMTS technology. UMTS networks are designed to be compatible for mode-switching with GSM, but they are fundamentally different technologies.
If you take a phone that has all GSM bands and no 3G support, and you insert a Bell or Telus SIM, you will get no signal. Therefore they are not GSM networks.
Click to expand...
Click to collapse
To put the argument to rest, 3GPP Sepcification:
The term "3GPP specification" covers all GSM (including GPRS and EDGE), W-CDMA and LTE (including LTE-Advanced) specifications. The following terms are also used to describe networks using the 3G specifications: UTRAN, UMTS (in Europe) and FOMA (in Japan).
Click to expand...
Click to collapse
Bell and Telus do not have GPRS/EDGE networks created, hence phones are not backwards compatible on those networks, you *must* have UMTS coverage to have a phone conversation if you have one of their SIMs. This however does not change the fact, UMTS is a third generation GSM technology.

Matridom said:
To put the argument to rest, 3GPP Sepcification:
The term "3GPP specification" covers all GSM (including GPRS and EDGE), W-CDMA and LTE (including LTE-Advanced) specifications. The following terms are also used to describe networks using the 3G specifications: UTRAN, UMTS (in Europe) and FOMA (in Japan).
Click to expand...
Click to collapse
Bell and Telus do not have GPRS/EDGE networks created, hence phones are not backwards compatible on those networks, you *must* have UMTS coverage to have a phone conversation if you have one of their SIMs. This however does not change the fact, UMTS is a third generation GSM technology.
Click to expand...
Click to collapse
The quote says nothing of the sort. The paragraph you have quoted says that GSM and UMTS are both 3GPP specified technologies. It does not mean that UMTS is a "GSM technology". It is needlessly confusing to refer to UMTS-only networks as GSM. If a network does not support a GSM-only device, it should not be described as GSM, end of story.

cmstlist said:
The quote says nothing of the sort. The paragraph you have quoted says that GSM and UMTS are both 3GPP specified technologies. It does not mean that UMTS is a "GSM technology". It is needlessly confusing to refer to UMTS-only networks as GSM. If a network does not support a GSM-only device, it should not be described as GSM, end of story.
Click to expand...
Click to collapse
Feels like an academia perspective.
To the average consumer GSM means that that it uses a SIM. Another example is the use of 4G to mean a certain speed, yet none of today's phones are 4g phones.
I guess the question is, are we discussing real world or academia?
Sent from my Galaxy Nexus using Tapatalk

cmstlist said:
The quote says nothing of the sort. The paragraph you have quoted says that GSM and UMTS are both 3GPP specified technologies. It does not mean that UMTS is a "GSM technology". It is needlessly confusing to refer to UMTS-only networks as GSM. If a network does not support a GSM-only device, it should not be described as GSM, end of story.
Click to expand...
Click to collapse
If you like, I can keep finding references:
http://www.gsma.com/mobile-technology/
http://en.wikipedia.org/wiki/High-Speed_Downlink_Packet_Access
http://www.intomobile.com/2008/10/1...sm-plans-for-canada-hspa-3g-networks-by-2010/
What you are confusing is GPRS with GSM.
GSM is an umbrella standard that incorporates many different techs, INCLUDING GPRS/EDGE (2G) and UMTS/HSPA(3G).
It's the difference between saying that all poodles are dogs vs all dogs are poodles.
What you are trying to say is that Telus and Bell do not support GPRS/EDGE which is correct. They DO support HSPA/UMTS which is in the GSM standard.
Edit: This thread is getting hijacked and i don't want that. Believe what you will, I won't be responding any more in this thread.

[Q] CDMA to GSM - is there any possibility

is there a possibility to make usable a CDMA phone to work in GSM...?

That depends there are patches some work but it depends on the the firmware like ics jb or gb I'm trying to get GSM to work on CDMA
Sent from my R800x using xda premium

darkharbinger81 said:
That depends there are patches some work but it depends on the the firmware like ics jb or gb I'm trying to get GSM to work on CDMA
Sent from my R800x using xda premium
Click to expand...
Click to collapse
so can u tell me where should be directed if u know for more information about this problem...?

I thought GSM required sim cards?
Sent from my SPH-L710 using xda premium

Yea, sim cards, frequencies, etc...
There is a lot more involved in the two different technologies than just "cooking" up a ROM.
I don't believe it possible to change a phone from gsm to CDMA and vice versa. Nor can it be tdma, or any other wireless technology. They operate on different bandwidths.
Think of it as attempting to transmit FM radio on a AM station.
Sent from my PC36100 using Tapatalk 2

cbucz24 said:
Yea, sim cards, frequencies, etc...
There is a lot more involved in the two different technologies than just "cooking" up a ROM.
I don't believe it possible to change a phone from gsm to CDMA and vice versa. Nor can it be tdma, or any other wireless technology. They operate on different bandwidths.
Think of it as attempting to transmit FM radio on a AM station.
Sent from my PC36100 using Tapatalk 2
Click to expand...
Click to collapse
Chuck Norris listens to AM radio on his FM radio...
Sent from my SPH-L710 using xda premium

cbucz24 said:
Yea, sim cards, frequencies, etc...
There is a lot more involved in the two different technologies than just "cooking" up a ROM.
I don't believe it possible to change a phone from gsm to CDMA and vice versa. Nor can it be tdma, or any other wireless technology. They operate on different bandwidths.
Think of it as attempting to transmit FM radio on a AM station.
Sent from my PC36100 using Tapatalk 2
Click to expand...
Click to collapse
Lets hope darkharbinger81 to make smth with his patches
Sent from my HTC Desire using xda premium

Two basic technologies in mobile phones, CDMA and GSM represent a gap you can't cross. They're the reason you can't use AT&T phones on Verizon's network and vice versa.CDMA (Code Division Multiple Access) and GSM (Global System for Mobiles) are shorthand for the two major radio systems used in cell phones. Both acronyms tend to group together a bunch of technologies run by the same entities. In this story, I'll try to explain who uses which technology and what the real differences are.
Which Carries are CDMA? Which are GSM?
Five of the top seven carriers in the U.S. use CDMA: Verizon Wireless, Sprint, MetroPCS, Cricket, and U.S. Cellular. AT&T and T-Mobile use GSM.
That means we're mostly a CDMA country. It also means we're not part of the norm, because most of the world is GSM. The global spread of GSM came about because in 1987, Europe mandated the technology by law, and because GSM comes from an industry consortium. What we call CDMA, by and large, is owned by chipmaker Qualcomm. This made it less expensive for third parties to build GSM equipment.
There are several variants and options carriers can choose, like toppings on their technological ice cream. In this story we'll be talking about U.S. networks.
For call quality, the technology you use is much less important than the way your carrier has built its network. There are good and bad CDMA and GSM networks, but there are key differences between the technologies. Here's what you, as a consumer, need to know.
It's much easier to swap phones on GSM networks, because GSM carriers put customer information on a removable SIM card. Take the card out, put it in a different phone, and the new phone now has your number. What's more, to be considered GSM, a carrier must accept any GSM-compliant phone. So the GSM carriers don't have total control of the phone you're using.
That's not the case with CDMA. In the U.S., CDMA carriers use network-based white lists to verify their subscribers. That means you can only switch phones with your carrier's permission, and a carrier doesn't have to accept any particular phone onto its network. It could, but typically, U.S. carriers choose not to.
In other words, you can take an unlocked AT&T phone over to T-Mobile (although its 3G may not work well because the frequency bands are different). You can't take a Verizon phone over to Sprint, because Sprint's network rejects non-Sprint phones.
3G CDMA networks (known as "EV-DO" or "Evolution Data Optimized") also, generally, can't make voice calls and transmit data at the same time. Once more, that's an available option (known as "SV-DO" for "Simultaneous Voice and Data Optimization"), but one that U.S. carriers haven't adopted for their networks and phones.
On the other hand, all 3G GSM networks have simultaneous voice and data, because it's a required part of the spec. (3G GSM is also actually a type of CDMA. I'll explain that later.)
So why did so many U.S. carriers go with CDMA? Timing. When Verizon's predecessors and Sprint switched from analog to digital in 1995 and 1996, CDMA was the newest, hottest, fastest technology. It offered more capacity, better call quality and more potential than the GSM of the day. GSM caught up, but by then those carriers' paths were set.
It's possible to switch from CDMA to GSM. Two carriers in Canada have done it, to get access to the wider variety of off-the-shelf GSM phones. But Verizon and Sprint are big enough that they can get custom phones built for them, so they don't see the need to waste money switching 3G technologies when they could be building out their 4G networks.

dimmy1405 said:
Lets hope darkharbinger81 to make smth with his patches
Sent from my HTC Desire using xda premium
Click to expand...
Click to collapse
How about I am currently porting a gsm rom to cdma?
Sent from my R800x using xda premium

But we are talking about cdma to gsm, more accurate evo 4g verizon operator...
Sent from my HTC Desire using xda premium

darkharbinger81 said:
How about I am currently porting a gsm rom to cdma?
Sent from my R800x using xda premium
Click to expand...
Click to collapse
Porting a GSM rom to CDMA is not the same thing as using a CDMA phone on a GSM network.

Diablo67 said:
Two basic technologies in mobile phones, CDMA and GSM represent a gap you can't cross. They're the reason you can't use AT&T phones on Verizon's network and vice versa.CDMA (Code Division Multiple Access) and GSM (Global System for Mobiles) are shorthand for the two major radio systems used in cell phones. Both acronyms tend to group together a bunch of technologies run by the same entities. In this story, I'll try to explain who uses which technology and what the real differences are.
Which Carries are CDMA? Which are GSM?
Five of the top seven carriers in the U.S. use CDMA: Verizon Wireless, Sprint, MetroPCS, Cricket, and U.S. Cellular. AT&T and T-Mobile use GSM.
That means we're mostly a CDMA country. It also means we're not part of the norm, because most of the world is GSM. The global spread of GSM came about because in 1987, Europe mandated the technology by law, and because GSM comes from an industry consortium. What we call CDMA, by and large, is owned by chipmaker Qualcomm. This made it less expensive for third parties to build GSM equipment.
There are several variants and options carriers can choose, like toppings on their technological ice cream. In this story we'll be talking about U.S. networks.
For call quality, the technology you use is much less important than the way your carrier has built its network. There are good and bad CDMA and GSM networks, but there are key differences between the technologies. Here's what you, as a consumer, need to know.
It's much easier to swap phones on GSM networks, because GSM carriers put customer information on a removable SIM card. Take the card out, put it in a different phone, and the new phone now has your number. What's more, to be considered GSM, a carrier must accept any GSM-compliant phone. So the GSM carriers don't have total control of the phone you're using.
That's not the case with CDMA. In the U.S., CDMA carriers use network-based white lists to verify their subscribers. That means you can only switch phones with your carrier's permission, and a carrier doesn't have to accept any particular phone onto its network. It could, but typically, U.S. carriers choose not to.
In other words, you can take an unlocked AT&T phone over to T-Mobile (although its 3G may not work well because the frequency bands are different). You can't take a Verizon phone over to Sprint, because Sprint's network rejects non-Sprint phones.
3G CDMA networks (known as "EV-DO" or "Evolution Data Optimized") also, generally, can't make voice calls and transmit data at the same time. Once more, that's an available option (known as "SV-DO" for "Simultaneous Voice and Data Optimization"), but one that U.S. carriers haven't adopted for their networks and phones.
On the other hand, all 3G GSM networks have simultaneous voice and data, because it's a required part of the spec. (3G GSM is also actually a type of CDMA. I'll explain that later.)
So why did so many U.S. carriers go with CDMA? Timing. When Verizon's predecessors and Sprint switched from analog to digital in 1995 and 1996, CDMA was the newest, hottest, fastest technology. It offered more capacity, better call quality and more potential than the GSM of the day. GSM caught up, but by then those carriers' paths were set.
It's possible to switch from CDMA to GSM. Two carriers in Canada have done it, to get access to the wider variety of off-the-shelf GSM phones. But Verizon and Sprint are big enough that they can get custom phones built for them, so they don't see the need to waste money switching 3G technologies when they could be building out their 4G networks.
Click to expand...
Click to collapse
Nice info. Knew some of that, but not all. Learned some good info. Thanks
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