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Discussion Starter · #1 ·
I know the AT&T iPhone 4S can do simultaneous voice and data but CDMA phones cannot do this with the exception of 4G LTE phones. However, I've seen posts online that say the Verizon/Sprint iPhone 4S can do simultaneous voice and data and some posts that say it can't. Does anyone know for sure?

The only reason I think it MIGHT be able to is because it has two antennas where one can transmit and one can receive and because it's a world phone with both CDMA and GSM radios. But, other world phones on Verizon can't do it.

Does anyone have a concrete answer? I don't even want the phone (screen too small from what I'm used to and Verizon's 3G is slow), I'm just curious.
 

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Alright here is the lowdown from my experience (im in the cellular technologies field)

CDMA phones are not built to provide simultaneous Data/Voice because of how the technology functions. Because Code Division multiple access uses one frequency with codes, Voice/data is not possible. Its either voice, or data. Not to mention no call waiting, because it cannot have two simultaneous calls.

The Iphone 4S from sprint has a preloaded Sprint world sim card in it. SO basically, if you are in the US, you wont see that SIM card being utilized. If you are OCONUS, you will (depending on roaming agreements worldwide), but on that note, Who knows if Simultaneous Data/Voice is locked out because it is primarily a CMDA phone.

It is said sprint will unlock the internal SIM on requests.

Note that this phone is NOT 4G NETWORK CAPABLE. It is CDMA EVDO REV A. 3G. Not 4G WiMax.

BUT! One advantage the Iphone 4S does have over the other networks, sprint is still offering their Unlimited Data Plan (for now).

This is all derived from my experience in the cellular communications field, BUT because I haven't had a chance to play with one yet, I could be off on the VOICE/DATA roaming with the internal SIM card provided from sprint.
 

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From ZD net and a verified sprint employee

Sprint's policy is to have the iPhone 4S SIM locked to our network domestically and internationally. At launch, the International SIM will be unlocked. We do expect a SIM lock to be pushed to the devices shortly after launch. We will then allow existing customers in good standing to unlock the SIM for international use if needed in the future.

Customers can sign up for one of our international rate plans and use this phone all over the world. When traveling internationally, there is a setting that must be turned on within the device to connect to GSM. The phone will work with a SIM that is provided within the device out of the box. International voice and data charges are on a pay-as-you-go basis and vary based on the country where the customer is using their phone; a list of rates is available at www.sprint.com/international.

Sprint offers two international voice plans that customers can subscribe to for discounted voice rates:

• The Canada Roaming add-on is $2.99 per month and all calls placed from Canada are only 20 cents per minute. Without this add-on, calls from Canada are 59 cents per minute.

• The Sprint Worldwide Voice add-on is $4.99 per month and offers discounted rates in countries around the world. For example, calls from Italy are $1.69 per minute with this add-on or $1.99 per minute without the add-on; calls from Peru are $2.29 per minute with the add-on or $2.49 per minute without it.

Sprint does supply notifications of data roaming charges to protect customers from high costs. Notifications are sent to the customer's preferred method, either text or email, and are sent once the device exceeds approximately $50, $250, $500 and $1,000. To protect the customer from additional charges, the device's international data roaming capability will be suspended after the customer exceeds approximately $1,000 of international data charges in a billing cycle.
 

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So you cannot replace the Micro-Sim, will not have access to it in the US, and it can only be used with international plans

So for Data/Voice in the US, its a no go (CDMA only network)

Voice/Data abroad? Most likely possible, but it might get expensive.

I hope this helps.
 

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This is accurate.

Quote:


Originally Posted by Sneaky Payload
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Alright here is the lowdown from my experience (im in the cellular technologies field)

CDMA phones are not built to provide simultaneous Data/Voice because of how the technology functions. Because Code Division multiple access uses one frequency with codes, Voice/data is not possible. Its either voice, or data. Not to mention no call waiting, because it cannot have two simultaneous calls.

The Iphone 4S from sprint has a preloaded Sprint world sim card in it. SO basically, if you are in the US, you wont see that SIM card being utilized. If you are OCONUS, you will (depending on roaming agreements worldwide), but on that note, Who knows if Simultaneous Data/Voice is locked out because it is primarily a CMDA phone.

It is said sprint will unlock the internal SIM on requests.

Note that this phone is NOT 4G NETWORK CAPABLE. It is CDMA EVDO REV A. 3G. Not 4G WiMax.

BUT! One advantage the Iphone 4S does have over the other networks, sprint is still offering their Unlimited Data Plan (for now).

This is all derived from my experience in the cellular communications field, BUT because I haven't had a chance to play with one yet, I could be off on the VOICE/DATA roaming with the internal SIM card provided from sprint.

 

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So basically:
On CDMA network - No
On GSM Network - Yes
 

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Right, if you want to talk and surf better hope you have wifi... for cdma.
 

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There are a few reasons why CDMA is becoming more prevalent in Japan and the US, and some other countries (US mainly though)

I will go over the Pro's and Cons associated with each, and then I will shut up.. I promise.

CDMA as it is used now (CDMA2000 and CDMA EvDO [ Evolution Data Optimized]) is a great way to "unclutter" the RF space (Radio Frequency space) in communications. here is why

GSM: uses multiple frequencies in a TDMA (Time division multple access) scheme for the uplink and downlink of voice and data.

Example: you have a cell tower, and it serves an area. There are 6 people utilizing that cellular tower for communications. They are all using GSM850 (GSM850 and GSM1900 are what is used in america for TMOBILE and ATT for Voice and SMS Bands)

Because GSM VOICE uses TDMA for the technology base, when person 1 calls person 2, they are using 4 different frequencies on that tower. IE person 1 is using 855.2MHZ for his Uplink and 885.2MHZ for his downlink (note this is just theoretical, and there are multiple frequencies allocated to providers, etc.) and person 2 is using 875.5 uplink and 865.5 for his downlink.

Now throw in guardbands so you dont get frequency bleed-over, etc, and you are using a great deal of RF space to communicate.

NOW for CDMA

say you have a CDMA tower, a common frequency range is 450mhz for CMDA.

Because CDMA phones use Code division multiple access, you and another caller, or another person on the same "cell tower" can be on the same frequency, because a "code" is applied to your call so it can be differentiated when transmitted and received.

so caller 1 and caller 2 can be on the same 450mhz frequency channel, and because their transmissions are coded (RX/TX) they can be differentiated even though they are on the same frequency. This is the beauty of a digital signal such as CDMA2000 and CDMA 1xRTT EvDO

Advantages of CDMA

Less frequency space use, therefor cheaper for the provider to lease and use and deploy
Faster data (on paper, but the USA sorta screws it up)

Disadvantages of CDMA

No Data/Voice at the same time (even on some 4G phones, with WiMax/LTE switch on, you still cannot browse and talk at the same time.

No actual encryption (because CDMA uses a digital signal with a sort of "frequency hopping" scheme, they say its "built in security". Its not. :-\\

GSM advantages

WorldWide use

Simultaneous Voice and Data (on most networks)

Faster data throughput

Good encryption (current standard in america is A5/1 and A5/3)

I hope this helps, or maybe I am just too talkative.

Anyone correct me if I am wrong/missed anything.
 

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I have sprint, and I really do not see the need for Voice/Data at the same time. How many people surf the web and talk at the same time on a phone..IMO only "super-users" such as people on this forum. but joe-schmo isnt going to notice.
 

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Quote:


Originally Posted by Sneaky Payload
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I have sprint, and I really do not see the need for Voice/Data at the same time. How many people surf the web and talk at the same time on a phone..IMO only "super-users" such as people on this forum. but joe-schmo isnt going to notice.

Yea, I have never had a need for it. I am either talking on using the internet, not both (but maybe I have and have not realized it?).
 

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it can be nice if your tethering... or want to use maps, or look something up quickly.
 

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Quote:


Originally Posted by Sneaky Payload
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I have sprint, and I really do not see the need for Voice/Data at the same time. How many people surf the web and talk at the same time on a phone..IMO only "super-users" such as people on this forum. but joe-schmo isnt going to notice.

i have used it many times.
mainly when i am talking to someone and need to look up something that deals with our current conversation.

i also know a ton of people who arent "power users" who do it as well.
 

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Discussion Starter · #15 ·
Quote:


Originally Posted by Sneaky Payload
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No Data/Voice at the same time (even on some 4G phones, with WiMax/LTE switch on, you still cannot browse and talk at the same time.

Anyone correct me if I am wrong/missed anything.

WiMax maybe, but I wasn't aware of any LTE phones that don't use SVDO (on Verizon).

Also, by CDMA is faster, are you referring to EVDO? Isn't the theoretical max between 3 and 4Mbps? Whereas HSPA is like 7.2Mbps and HSPA+ is 14.4?
 

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You are correct on the Verizon phones. Sorry about that.

EVDO real world speeds (US BASED) on the high end (major markets) are more around 7-8Mbps if using 1xEV-DO, I have seen it, mapped it, and tested it.

One thing I will say about 3g data on verizon and sprint, is that it is more dependable in major market areas

HSPA is supposed to be flaming fast, but since ATT and Tmobile are a bunch of non-standard using morons, its random. you will see it hit 22 megs for a minute, then down to 2 megs depending on how many users are trying to access the 3g+ (because in the standard, set by the international community HSPA, HSPA+, HSDPA HSUPA are NOT 4g technology. They are MAX 3.5G)

So as far as the SPEC goes? yes. HSPA and HSPA+ are faster. But CDMA has better range and less issues.
 

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Quote:


Originally Posted by Agueybana_II
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Good to know. I am interested in the I-Phone but can't make up my mind on the carrier.


Truthfully, the IPhone is a better AT&T product. for the above stated reasons.

If you do not need simultaneous voice/data, I would jump on sprints with their unlimited data still in effect, and be grandfathered in!
 

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The fastest I've ever seen on Evdo rev a sprint is 2.7 in nyc, a major market.



this is "4g" on an epic (tethered) I really think that thats a fast as anyone would ever need on a phone.

In fact I'd be pleased with 2.5 everywhere I go.
 

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Discussion Starter · #20 ·
Quote:


Originally Posted by Agueybana_II
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Good to know. I am interested in the I-Phone but can't make up my mind on the carrier.

Sprint's pricing is more attractive but AT&T provides faster data and obviously the ability to do simultaneous data/talk.

I had the Verizon iPhone 4 awhile back and it was okay, when I got rid of it I missed it but I also missed Google Navigation.
 
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