Carrier Dual Sim: Picking data line -- how does it work?

[voraciousvegan]

I can't figure out how picking the data line for Dual Sim works.

I have one line with unlimited calling, text, & data. I want to get a second business line I can call & send iMessages with, but want to avoid buying data if I can use the data from my FIRST line to send iMessages.

Line A: unlimited call, text & data
Line B: unlimited call & text -- NO DATA

If I set data to Line A, will I be able to send & receive iMessages on Line B using Line A's data? Or will it just fall back to SMS?

 

[Nahmeanz]

If I set data to Line A, will I be able to send & receive iMessages on Line B using Line A's data? Or will it just fall back to SMS?

Yes,

Settings > Cellular > Cellular Data > Line A
Settings > Messages > iMessage (On) / Send & Receive (Line B)