[settings/cellular] one single "connection type" section is not intuitive for multi SIM phones

[Jonas G. Drange]

Reading the spec[1] for cellular settings on the phone, it seems that 7 needs some further specification for multi SIM phones.

Imagine a user that wants to change the radio technology preference on SIM #1 to 3G and set the same setting on SIM #2 to 2G.

Until the split [2] we have been changing the radio technology preference of the currently online SIM, but 7 of [1] makes this impossible.

Imagine the spec being implemented:

1. Unlock two SIM cards
2. Open Ubuntu System Settings, go to 'Cellular'
3. Turn off cellular data
4. Set radio technology preference on SIM #1 to be 3G and SIM #2 to be 2G

What happened:
There's no way to change both SIM cards using only one selector.

What should have happened:
I should have been able to change both SIM card's radio technology preference independently.

If this is to be solved by adding yet another selector to the 'Cellular' Ubuntu System Settings panel, we could ask:
* Is this panel, for multi SIM phones, growing too large and confusing?
* Would stacking the SIM cards and their preferences horizontally save space and be more intuitive? E.g. [3] This means listing the SIM identifier only once.

[1] https://wiki.ubuntu.com/Networking#phone-cellular
[2] https://bugs.launchpad.net/ubuntu/+source/ubuntu-system-settings/+bug/1378812
[3] http://i.imgur.com/7mmKraN.jpg

<https://wiki.ubuntu.com/Networking#cellular-connection>: "The “Connection type” screen should contain a radio list for each SIM. If there is more than one, each should be introduced by its SIM name."

[Matthew Paul Thomas (mpt)]

Why do you want "SIM #1 to be 3G and SIM #2 to be 2G"? Is this because the radio tech setting influences voice calls, not just data?

[Matthew Paul Thomas (mpt)]

To clarify, the reason there is only a single radio tech setting is that I understood (A) it applied only to data and (B) only one SIM can use data at a time. If either of those isn't true, then we need a radio tech setting for each SIM. (And if B isn't true, that opens a can of worms about which SIM uses data when.)

[Jonas G. Drange (jonas-drange)]

A is false, based on excerpt from chat below:

mpt jgdx, awe_: Does the “Connection type” (radio tech) setting affect just data, or does it affect data and also voice? 15:56
awe_ mpt, both... this is the basis for the whole split SIM data selection / radio tech change 16:00 [1]

B is true from a user point of view.

[1] http://irclogs.ubuntu.com/2014/12/12/%23ubuntu-touch.html

[Matthew Paul Thomas (mpt)]

Specification updated. <https://wiki.ubuntu.com/Networking?action=diff&rev2=250&rev1=249>

[Matthew Paul Thomas (mpt)]

(This should not be assigned to me for testing, because I don't have a dual-SIM phone.)

[Jonas G. Drange (jonas-drange)]

Let me know if you want me to produce step by step instructions on how to
test it on your desktop/virtual machine that runs Ubuntu.

[Matthew Paul Thomas (mpt)]

(I have located a dual-SIM phone. \o/ )