it can be used concurrently, but only one sim is connected to the 3g network
Thanks for your reply.
So an example I would be fitted in two SIM cards (ie: SIM1 & SIM2)
If I enabled data (3G usage) for SIM1, I would be able to FB, instagram, Whatsapp, etc. on top of answer/making calls & SMS.
For SIM2, can only use for phonecall and SMS (since without data being enabled).
However, if the two SIM cards are of two different networks, do i need to do anything in regards to the "network selection"?