[systemz]

Yes, I was suggesting just that. In that case, at least in EU there is an option when one number can be used on more than one SIM card. Then using second SIM slot on both phones you have access to that number. Incoming SMS goes to both number I think. Calls can be answered by any phone but faster to answer wins.

[hluska]

It works in many providers in Canada too.

Our mobile networks just recently upgraded from two tin cans and a really long string so I feel like if we support it, it must be pretty close to universal.

[tcrhelpforsms]

I have not heard of such a thing in the US, but I will investigate.

So while that would work for calls, does that also behave as expected for SMS and MMS?

[systemz]

What I remember from my case few years ago, incoming SMS were handled to both SIMs. Outgoing SMS from my number didn't appear on second one (so shared SMS history isn't complete in that sens). I didn't use MMS. I think all those behaviors can be different, depending on provider config.

[tcrhelpforsms]

Okay, that is a problem then. If both phones cannot see all messages, how would both parties have full context on the conversation? This would inevitably lead to both of us sending a response.