Hi I've a shared data plan with my provider - currently with 2 phones and a tablet. For tablet to share the data i pay $10 extra monthly. But when i put the sim into a new iphone 5c (which i bought as a gift for someone) smartphone it acts like a normal phone (both the tablet and phone have the same type of sim card) - i can call into this number and it rings!!.. Not sure how this works. The tablet sim is supposed to be only to share data no voice..how does it ring then when i put in in the phone? Will i be charged for voice if someone calls this number?