A system and method described for tracking portable devices. The system may include
a transmitter which transmits wireless inquiries to a plurality of portable devices
and a receiver receiving replies to the inquiries from the portable devices. In
addition, the system may include a memory storing identifier data corresponding
to the portable devices and a processor coupled to the memory and to the receiver,
the processor retrieving from each reply, identifier data uniquely identifying
a particular one of the portable devices which generated the reply and comparing
the identifier data to the stored identifier data. Furthermore, the system may
include an alarm system coupled to the processor and controlled based on the comparison
of stored identifier data to the identifier data retrieved from the replies.