Originally Posted by NJBlackBerry
Yes, you need a regular phone plan. Otherwise the phone doesn't have a number. So it can't call. UMA still uses your phone plan. I don't believe you can have Hotspot (or whatever they call it now) without a voice (and data) plan.
If the phone has a SIM card, then it has a number, but if the SIM isn't provisioned with a voice plan (i.e., a data only BlackBerry), then calls are charged at a per-minute rate. If the phone doesn't have a SIM card, then you are correct, it cannot call.