Voice Calls only on GSM!

I started using Mudita Pure for the last 10 days. My observation is that for the voice calls, I see “2G” (GSM) on the display next to signal strength indicator during the entire call. Once the voice call is over, it shows “LTE” (“2G” not displayed after the call) for one second and then nothing shows next to the signal indicator.

Is Mudita Pure use only “GSM” for calls? In that case what is “LTE” for? No voice over LTE support on this device?


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@ramamohan That’s a very interesting observation. I will definitely pass this on to the team & go over your concerns. In the meantime, could you please send logs from your phone to Mudita, so our team can try to recreate the issue.

@urszula, I’m sharing video snapshots of one of the sample the voice call with Mudita Pure. I uploaded the snapshots as video can’t be uploaded. It switches to 2G while on voice call and at the end of the call, LTE appears for a second and vanishes. I observed this for every voice call, irrespective of my location when calling (I mean home/work/market).

I went through the SAR information details in the help section of “Mudita Center” application. Part of the important note is copied here.

"Our solution uses 2 antennas with dedicated shielding and specially written software to minimize exposure to radio waves.

The antennas switch to the one with better parameters to minimize SAR, but also to keep signal integrity. When scanning the network (what the modem does automatically) we get information which band has what signal level, comparing it to the maximum SAR values measured in a certified laboratory, we know which antenna to choose. Due to the characteristics of the antenna, one works better in low bands, the other one in high bands. However, often in bands which operate together with good parameters, we choose the one with lower SAR."

I believe Mudita focus is on SAR rather than signal power / better service (2G/3G/4G). So it choosing the 2G for voice calls. I face lot of calls drops and bad call quality (Me cant hear other party or other party can’t hear Me or both can’t hear each other).

I live in a city where 4G is well deployed. I used Light Phone 2 which has no problem of voice calls. Only problem with Light Phone 2 is, it doesn’t support LTE TDD bands. So in some areas where only TDD band deployed, Light Phone 2 doesn’t work.

I assume there should be a software change that can make call quality given preference than low SAR antenna / low power technology. If this can’t be done, then this phone is not useful to me. Your patented antenna technology for low SAR is useless if call quality is bad.

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@ramamohan Thanks for all this feedback. I will share this with the team. I can clearly see the LTE. Who’s your service providers again? Did you have a chance to send the logs to our dev team via Mudita Center?

I don’t have any problems during conversations, I understand my conversation partner very well and I am also understood very well. Nevertheless, I always switch to 2G for calls. The Mudita service told me that this is normal and that Voice over LTE is not available on the Pure. As I said before, it would be great if you could decide for yourself whether you want to make calls in 4G or 2G. Or whether low SAR values or better signal quality is more important.

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Hi @urszula, I’m thinking of how can I save logs when I find some voice call is not good at all. I can’t connect the device to PC whenever I receive/make a call. Is there any other method?

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Hi @marko, thank you for your reply. I don’t mind if it is 2G or 3G or 4G call. Only wish is if the call is not going alright in one Tech (lowest SAR), it should switch to other Tech (that may have high SAR compared to previous Tech on the call). This way the call is sustained without either party having problem listening to each other. I experience 50% of the calls are bad.

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@ramamohan You don’t need to be receiving the calls in order to send us the logs. Our team will be able to see if there are any bugs in the logs, just from looking through them.

I did that following the procedure in the link How to send logs to Mudita via Mudita Center

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Today I made two calls. The first call, I can’t hear anything from the other party. Second call was Ok. I shared the logs.

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@ramamohan What is the serial number of your phone?


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@ramamohan I am passing it on & they will look into it.

Thank You @urszula

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Please be advised that Pure will use 2G and 3G for voice calls. LTE is used for data packets only. I hope this helps :slight_smile:

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Thank You @Grzegorz_Szmidt for the confirmation.

Any clues from the logs why the call quality is so bad? It can’t be a network issue, as other phones work well in the same location.

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@ramamohan Where are you located at & what network provider are you using?

Hi @urszula, I live in Hyderabad, India. Service provider is Airtel. The same SIM card when I use on LP2/Google Pixel 4A, I don’t find voice quality bad and no call drops.