Samsung Messages RCS issues

[Adi0]

 

Hi, why can't I make my SIM 1 default for RCS chats? It only wants to use the SIM 2, I have no option to choose. 

[BandOfBrothers]

Possibly a question for Samsung via your Samsung Members App if you haven't already @Adi0 

[Reylob]

Hi @Adi0 

Did you make your SIM1 the default SIM for Mobile data?

Settings -> Connections - SIM Manager -> Mobile data ( select the appropriate SIM, SIM1)

That should make SIM1 the default.

[Adi0]

But I want to use the SIM 2 for data. 

[Reylob]

Well that is a conundrum. RCS needs the mobile data and mobile data can only be active on one SIM at the time. To have mobile data on both SIM the phone needs the hardware to do it, two modems.

So, using SIM2 for Mobile data and SIM1 for RCS is not possible on most mobile phones. I do not know if there is one with two modems.

[Juli3n]

I'm not an expert but I always thought dual SIM. devices had 2 modems, that's the whole point of them, connecting to 2 networks at once. The limitation is software I would say, as in the device needs 1 connection at one time (same if you have WiFi and mobile data enabled), so you have to pick which SIM to use.

[Reylob]

I thought that one of SIM was standby for that reason.

[Reylob]

Hi @Juli3n 

My previous reply was on my phone whilst walking. Technically they could have to modems and behave in the manner you describe. But as far as I can remember most dual SIM phones are standby, not active (two modems). The S24 series is dual standby, meaning only one SIM can be able to do Mobile data. Software alone cannot fix that.

[Juli3n]

Yea I wasn't implying this was an issue that could be fixed by software, just that the problem shouldn't be hardware. For example with the WiFi and mobile data example, they obviously have the hardware for both, but we can't use data at the same time from both. The device needs to pick one. But as you said for the SIM it could be dual standby indeed, either way as you said originally, only one thing can provide internet at one time. Now saying that, if the device had a data connection (either from WiFi or another SIM) you'd think that you should be enough for RCS, since it doesn't need to use mobile data on the other SIM?

[Adi0]

Do you know that I'm using SIM 1 for RCS in Google Messages and it works, while SIM 2 is being used as a SIM for mobile internet. So yeah, Samsung should let us use whichever SIM we want for the RCS, regardless of which on is set to for the data...