A method and apparatus for modular authentication of a wireless communication device (120) including a portable communication device (210) and a wireless communication module (220) coupleable thereto is disclosed. When the wireless communication module (220) receives information (706) from the portable communication device (210), it determines whether the information received is authentic information (710) and operates together with the portable communication device (210) as a wireless communication device (120) in a communication system (100) in response to the information received being authentic information (720). In addition, a method and apparatus is disclosed for checking subsidy lock in a wireless communication device (120) capable of operating in a communication system (100), the wireless communication device comprising a first module (210), a second module (220) and a subscriber identity module (230) coupled to the first and second modules (210, 220). The first and second modules (210, 220) independently determine whether subsidy lock information stored in the subscriber identity module (230) corresponds to correct subsidy lock information (614, 618), and set a state of the wireless communication device (120) as operable in the communication system (100) in response to determining that the subsidy lock information stored in the subscriber identity module (230) corresponds to the correct subsidy lock information (614, 618).