# Simultaneous Voice & Data on VZW - even 3G?!



## bobukcat (Dec 20, 2005)

When I first read this I got really excited thinking it was finally confirmation that VZW will support voice & data on their LTE network (possibly using 3G for Voice and LTE for data) but then I realized the Thunderbolt is not an LTE (or 4G) device and re-read that is says it will do this on the 3G network...what?!?!? 

There is a lot of speculation on how this is being achieved but nothing official other than VZW stating that it's not consistent with the brand so don't tout the feature too much when selling it. I suppose it could just mean that since it is the first (and so far only) device that supports this they don't want people thinking it's a big deal and if they don't like the Thunderbolt for some reason they would go to AT&T to get the functionality.

http://phandroid.com/2011/01/26/simultaneous-voice-and-data-over-3g-confirmed-for-htc-thunderbolt/


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## Stuart Sweet (Jun 19, 2006)

It's got to be some sort of hack in the phone. Maybe the phone is using 3G for VoIP. I don't know too much about that phone, but I do know that CDMA technology does not allow for simultaneous data. It's something about the way the phone obtains a lease from the cell tower. So, it would have to be a trick the phone was playing on the user. 

This limitation of CDMA has always been there as far as I know, and Verizon will continue to have the issue until they switch to LTE-Advanced.


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## bobukcat (Dec 20, 2005)

Some are suggesting that it may be utilizing new features of the CDMA2000 1X Advanced System but I don't recall ever seeing any release that VZW was deploying that system and would question why they would if LTE is so close:

http://www.cdg.org/news/press/2009/Aug17_09.asp



> A complementary device enhancement known as simultaneous 1X Voice and EV-DO Data (SVDO) will also become available during the same timeframe and will enable CDMA2000 devices to access EV-DO packet data services while in an active 1X circuit-switch voice call. For example, users will be able to send emails or access the Web while on voice calls; phones with GPS can update maps or download real-time traffic information while on voice calls, etc. This device enhancement, which enables these concurrent voice and data services, is independent of the air link standard and infrastructure.


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## Beerstalker (Feb 9, 2009)

Actually, the last I read is that it isn't exactly a limitation of CDMA, just a limitation of the majority of the exsting CDMA chips that the phone manufacturers are using. There is supposedly a new chip available that allows simultaneous voice and data on CDMA networks, but nobody had bought it and put it in a phone as of the time I was reading about it. Sounds like this new phone must be using that newer CDMA chip.


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## davring (Jan 13, 2007)

Beerstalker said:


> Actually, the last I read is that it isn't exactly a limitation of CDMA, just a limitation of the majority of the exsting CDMA chips that the phone manufacturers are using. There is supposedly a new chip available that allows simultaneous voice and data on CDMA networks, but nobody had bought it and put it in a phone as of the time I was reading about it. Sounds like this new phone must be using that newer CDMA chip.


I read that the chip is available and Apple would'nt put it in the VZW iPhone because it was too power hungry.


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## Shades228 (Mar 18, 2008)

I'm betting that carriers have said that if a phone uses a new chip like that they will have a surcharge for that phone on the plan. Considering it would take 2 CDMA channels it effectively is 2 devices. I'm betting it will be limited in use and most will hold out for LTE advanced which all phones of that type will get charged more for and not be specific. I'm not sure if I would pay additional just to use data and voice at once, but I don't talk on my cell phone that much. It's more of a portable tablet.


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## ctorg (Mar 2, 2006)

Don't know if this will help - had a Sprint curve (8330- in year 2008/09) then tour (8530 in year 2009/2010) that would do voice/data combo or voice/sms combo. I do most of my work on the road and it became common to get things done. Now I have a company Verizon curve (newest one, don't know the model number, started using end of 2010 to current). Can't do voice/data combo anymore but have used voice/sms a few times lately. Both are CDMA carriers - so I would think it is a function of the 'newer' phones chips or a Verizon issue.


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## bobukcat (Dec 20, 2005)

ctorg said:


> Don't know if this will help - had a Sprint curve (8330- in year 2008/09) then tour (8530 in year 2009/2010) that would do voice/data combo or voice/sms combo. I do most of my work on the road and it became common to get things done. Now I have a company Verizon curve (newest one, don't know the model number, started using end of 2010 to current). Can't do voice/data combo anymore but have used voice/sms a few times lately. Both are CDMA carriers - so I would think it is a function of the 'newer' phones chips or a Verizon issue.


Don't confuse SMS with Data, all CDMA (and GSM for that matter) systems can do SMS and voice at the same time because SMS messages are sent over the voice channels, not a data channel. It's also why you could get SMS on phones that don't have data plans.

MMS is a different story, those are sent over the data channel.


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## ctorg (Mar 2, 2006)

Correct - I did confuse it when I wrote it last night. Didn't intend to confuse the discussion. To be clear - the sprint BB I used did data (internet/email) while on a phone call. The verizon BB does not let me access data use while talking.



bobukcat said:


> Don't confuse SMS with Data, all CDMA (and GSM for that matter) systems can do SMS and voice at the same time because SMS messages are sent over the voice channels, not a data channel. It's also why you could get SMS on phones that don't have data plans.
> 
> MMS is a different story, those are sent over the data channel.


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## dpeters11 (May 30, 2007)

bobukcat said:


> Don't confuse SMS with Data, all CDMA (and GSM for that matter) systems can do SMS and voice at the same time because SMS messages are sent over the voice channels, not a data channel. It's also why you could get SMS on phones that don't have data plans.
> 
> MMS is a different story, those are sent over the data channel.


I believe it technically goes over the control channel which doesn't carry voice, but we're basically talking about 25 year old technology that they still charge $1300 a megabyte for if you don't have a texting plan.


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## bobukcat (Dec 20, 2005)

dpeters11 said:


> I believe it technically goes over the control channel which doesn't carry voice, but we're basically talking about 25 year old technology that they still charge $1300 a megabyte for if you don't have a texting plan.


Yeah, what do you think their margin is on those texting plans and charges for exceeding the limits??? :eek2:


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