A security protocol may be implemented on a processor-based system by providing a wireless signal to a handheld device normally carried by the user. The locking mechanism includes a wedging unit, a locking unit and a pushing element. The cartridge port includes a cartridge securing arrangement for releasably securing a leading cartridge end therein and a cartridge ejection arrangement for at least partially ejecting a cartridge therefrom for assisting manual sliding ejection of a filled cartridge. A next latch circuit latches the second most significant bit of the control signal similarly, and a third latch circuit latches the remaining bit of the control signal. Determining individual consumption can be performed using minimum least square estimation, singular value decomposition, discriminant function analysis, or other computational or analytical solution method.