An RFID system comprises an RFID reader configured to issue an RF command requesting
that RF tags identify themselves, and to issue timing information defining a plurality
of timeslots; and a plurality of RF tags in selective communication with the reader,
the RF tags having respective IDs, respective tags being configured to randomly
select a timeslot in which to reply to the RF command, and to issue an RF reply
in response to the RF command in the randomly selected timeslot, the RF reply including
a frequency pattern to assist in identifying the tag but not the tag's entire ID,
different tags having different frequency patterns.