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  1. Thread Author  Thread Author    #1  

    Default Simultaneous voice & data?

    I got my Maxx back in December as a warranty replacement for a RAZR MAXX HD after I cracked the HD's screen. I just noticed yesterday that the Maxx can't seem to handle simultaneous voice & data. Is that a change with 4.4, or has that always been the case with this phone? The RAZR Maxx HD could do both at the same time, as could my Thunderbolt before that. I'm really going to miss that feature.

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  2. Thread Author  Thread Author    #2  

    Default Re: Simultaneous voice & data?

    Nevermind! I was using the LTE OnOff app to throttle my data down to 3g. Apparently this phone can't do both voice & data together when it's set to 3g only (the RAZR Maxx HD and Thunderbolt both could). Once I switched it back to a 4g signal I found that I can one again use voice & data simultaneously.

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  3. #3  

    Default Re: Simultaneous voice & data?

    It only works when your on 4g or 3g with Wi-Fi. Were you perhaps in a 3g zone with no Wi-Fi access

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  4. #4  
    CharlesH's Avatar

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    Default Re: Simultaneous voice & data?

    Quote Originally Posted by NotFromHere View Post
    Nevermind! I was using the LTE OnOff app to throttle my data down to 3g. Apparently this phone can't do both voice & data together when it's set to 3g only (the RAZR Maxx HD and Thunderbolt both could). Once I switched it back to a 4g signal I found that I can one again use voice & data simultaneously.
    If you are on a CDMA system such as Verizon, the 3G data protocol (EV-DO) does not support voice calls. On 3G, you are using the EV-DO data protocol, or the CDMA voice protocol, but not both at the same time. The 4G LTE radio is independent of the the CDMA radio, so you can use LTE data and CDMA voice at the same time (except on iOS devices, but this is an Android forum, so forget that). On GSM systems such as at&t, their 3G data protocol supports both voice and data, so it is not an issue on those systems.
  5. #5  
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    Default Re: Simultaneous voice & data?

    The HTC Rezound and Samsung Galaxy s3 used to do voice and data over 3G also. Not many Verizon phones do.

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  6. #6  

    Default Re: Simultaneous voice & data?

    Quote Originally Posted by CharlesH View Post
    If you are on a CDMA system such as Verizon, the 3G data protocol (EV-DO) does not support voice calls. On 3G, you are using the EV-DO data protocol, or the CDMA voice protocol, but not both at the same time. The 4G LTE radio is independent of the the CDMA radio, so you can use LTE data and CDMA voice at the same time (except on iOS devices, but this is an Android forum, so forget that). On GSM systems such as at&t, their 3G data protocol supports both voice and data, so it is not an issue on those systems.
    Certain models on Verizon, the HTC Thunderbolt & Rezound, and the Galaxy S3, have a feature called SVDO, which allows voice and data without an LTE or WiFi signal being present. It's not a feature that Verizon advertises (for whatever reason), but it is a feature that does exist. I know because I had each of those phones and tested them, because I live in an area without LTE, and they worked. However the data, as you may expect on 3G, is very slow, which is probably why Verizon doesn't advertise it.
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    CharlesH's Avatar

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    Default Re: Simultaneous voice & data?

    Quote Originally Posted by vzwuser76 View Post
    Certain models on Verizon, the HTC Thunderbolt & Rezound, and the Galaxy S3, have a feature called SVDO, which allows voice and data without an LTE or WiFi signal being present. It's not a feature that Verizon advertises (for whatever reason), but it is a feature that does exist. I know because I had each of those phones and tested them, because I live in an area without LTE, and they worked.
    Thanks for the correction. I forgot about SVDO. As I recall, the way they do it is to provide two independent radios, one for 2G CDMA voice, one for 3G EV-DO data. As I recall, there are some battery usage issues with this, due to running both radios. That is the only way to work around the fact that EV-DO, the 3G data solution on CDMA systems, does not support voice.
    Last edited by CharlesH; 01-21-2014 at 01:06 AM.
  8. #8  

    Default Re: Simultaneous voice & data?

    I think you're correct about it being 2G voice & EVDO for data, but there shouldn't be any difference in battery usage, since with the other ways you're using either 3G voice/LTE data or 3G voice/WiFi data, and either option uses 2 radios. But all I know was it was kind of a janky setup.

    Before they decided to re-engineer the Thunderbolt for LTE, it was supposed to have SVDO and be able to run simultaneous voice and data, something AT&T was using to show how inferior Verizon was in their ads at the time. The original iteration of the TBolt was their answer to those ads. But I think they decided to wait for LTE because of the sub par performance of SVDO. Even though it carried through to final version of the TBolt, I recall seeing a leaked document that told employees not to advertise it as a feature because they couldn't guarantee decent performance.

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