Have a double sim in phone, how do I know which one is using data?

[textbook]

Got two sims in my phone, which I'm trying out for the first time. Thinking of using one for work so personal number isn't all over net. How do i know when I'm using data which sim it's getting data from?

 

[johnb35]

Actually I think one is sim and one is a microsd card.

 

[Darren]

Actually I think one is sim and one is a microsd card.

Dual SIM phones are definitely a thing, more common in overseas markets where you're bouncing between different Wireless infrastructure types/carriers.

What phone we talking here?

This link is probably a good place to start.

https://www.digitalcitizen.life/set-dual-sim-smartphone-android-default-sim-calls-sms-data/