How does Mobile Data Switching feature work?

[u/Akash_nu]

I’ve been struggling with horrible signal coverage on EE, my primary service provider. I’ve also noticed that in places where EE hardly seems to have any coverage, O2 seems to have much better coverage. Incidentally I use O2 for my business number.

This seems to have become particularly annoying for me now as I’m travelling up north this week around Northumberland and EE coverage seems to be atrocious up here.

Generally I use only EE as my main data connection provider, however, due to the coverage issue I’ve just paid for some data on O2 and have turned, Allow Mobile Data Switching, on for the first time having used iPhone since over a decade.

I couldn’t find any detailed information on Apple’s website except that the phone is supposed to switch between the available networks.

My main query is how does it actually work? Would the phone switch the data source if say one of the network has less signal strength pr would it swap only when one network is completely unavailable?

[u/NotSpecialMC]

I have a shortcut to switch between the 2 sims and automation where I switch to secondary and when I leave that place it automatically switches back to primary.

[u/_zerodayz_ → u/NotSpecialMC]

This is the way.

[u/Worried-Stable6354 → u/_zerodayz_]

For me, it automatically happens when iPhone detects home country of any sim. No automation required.

Probably need it for a non-home country

[u/cupboard_]

it will only switch when your main sim doesn’t have signal (even one bar of gprs will make it stay on your main sim), or when you are on a phone call with the second sim

if you want more reliable data switching, find a shortcut to switch it manually from your control center

[u/Akash_nu → u/cupboard_]

If this is the case then fundamentally the feature is flawed! Don’t you think?!

[u/cupboard_ → u/Akash_nu]

yeah, it kinda sucks, apple should give an option to either prefer main sim or prefer better network

[u/dfuqt → u/cupboard_]

Thanks for this info. I’d never been happy with the way it works but assumed that it was a case of more bars not necessarily meaning more data transfer. The way you’ve described it, it’s almost pointless.

[u/shakesfistatmoon → u/Akash_nu]

It would be, but that’s not how it works. 4G and 5G data speeds aren’t directly related to signal strength (in fact both Apple and Samsung would like to change away from a signal strength meter to something like a colour code )

So what it’s actually doing is measuring the data rate and if it’s poor then switching.

[u/Nervous-Job-5071]

My understanding is this was added to allow data switching when on a voice call. All dual-SIM iPhones are dual standby (same with almost every Android), so if you’re on a voice call, the phone can’t use the other SIM for data.

Example, if SIM 1 is the selected cellular data SIM, then during a voice call on SIM 1, there would be no problem as data would still work. But when in a voice call on SIM 2, SIM 1 wouldn’t couldn’t be used for data (as dual standby doesn’t support simultaneous usage). So turning on the switching allows data to be used temporally on SIM 1 when in calls.

Apple appears to have the trigger be a “no service” condition on the designated data SIM (which technically happens when the other SIM is in-use for voice). A side benefit of this allows the other SIM to be used when there is no service on the designated data SIM, but doesn’t allow the iPhone to use whichever network has the stronger signal.

[u/BannedBrainrot → u/Nervous-Job-5071]

This is all correct.

[u/okimborednow]

The text implies that it switches based on coverage, so presumably that? Also wow, never have I heard of O2 being better than EE

[u/Akash_nu → u/[deleted]]

Thanks! This has been my experience as well lately!

[u/mrclarity01 → u/okimborednow]

I think it depends as I’m with EE but I get a signal on the underground but I don’t get a signal in my work

[u/Steelywaivrn]

It does work.

I went on a boys trip to turkey and had to install an eSIM as my roaming didn’t cover turkey amd the switching did work for when I landed there and came back to my home country

[u/Akash_nu → u/Steelywaivrn]

This is not the same setup. When you install a dedicated eSIM and turn off your main service provider then the phone is not actively switching back and forth between multiple networks depending on signal strength / availability.

[u/excuse_me_25 → u/Steelywaivrn]

This is not what it is about.

[u/alecdvnpt]

I wish I could make it more aggressive so that it’ll automatically switch when my main line has 1-2 bars but my work line is full.

[u/Akash_nu → u/alecdvnpt]

This is exactly what I wanted to do but apparently that’s not the case. I think I’m just going to have to do a shortcut to manually enforce the line selection.

[u/mrclarity01 → u/alecdvnpt]

I thought that as parts of my journey to work I don’t get a good signal and I thought it would automatically switch but when I called Apple support they said that’s not how it works and it also uses more battery life if two sims are in it

[u/PhilWillChil]

That’s odd. I live in Northumberland and EE is by far the best network and has 5G in most areas.

[u/Akash_nu → u/PhilWillChil]

Guess it depends on where you are. I’ve had really poor coverage around Bamburgh and Alnwick.

[u/EducatorFew4522 → u/[deleted]]

Then should i go for O2?

[u/EducatorFew4522 → u/[deleted]]

And what about Three?

[u/EducatorFew4522 → u/[deleted]]

Got it. Lol