Am I understanding this right? It means a student must have a phone and must carry it with them always (or at least almost always)? Does the phone also have to

Am I understanding this right? It means a student must have a phone and must carry it with them always (or at least almost always)? Does the phone also have to have a subscription, ie, is the student required to pay one of the cell phone service providers for the privilege of having a student ID?