I tested VOLTE with two different S10 with the same SIM.
On my phone I'm not able to recieve or make a calls when I'm in location with 4g/LTE reception only. Internet and SMS work fine in the same place. If I go to Settings->Mobile networks there is NOT option "VOLTE calls" at all. When I make a call, phone will switch to UMTS (3g network), so I'm able to make a call only in areas where 3g is available.
With the same SIM card on my friend's phone, "Enable Volte" option is in the menu. and he is able to make calls over 4G network.
I'm in contact with "Samsung service center" and trying to sort this isue out since January this year. No one is able to get my phone works correctly. All I want is to have a phone working as should be and not run between "Service" and "Store" in unfineted circles, one is saying it is a SIM card fault other is saying it is a phone fault.......
Model of both phones is SMG-973F, software version is the same and both have a last version of Android. Only diference I can see is in Service provider software version.
My version is SOAMC_SM-973F_OXM_NZC_RR_0005 NZC/NZC/NZC
My friend has SAOMC_SM-G973F_OXM_TNZ_RR_0005 TNZ/TNZ/TNZ
But... my phone was in "Samsung service center" they didn't repair it, but they completaly refresh all software in my phone. It is still not working 😞
Thanks for answer. Martin
VoLTE service is defined by a network carrier
observe, the CSC codes of both phones are different (NZC and TNZ)
which means they have different networks
to sort this, contact the network carrier which does not have VoLTE service
this is due to stock firmware of the phone are coming from them
thanks for answer, network carries has VOLTE enabled.
If I put my SIM card (same network carrier) to S21 from same network carrier or to S9(older model with SAOMC_SM-G960F_OXM_NZC_QQ_0008 NZC/NZC/NZC) calls over 4g works with the same simcard and carrier.
If the problem is to change CSC codes(file), why no one did it in last 4 months to get phone woks correctly?
I can do it if you are sure it will help. Thanks Martin