A conveyor system for processing items on which radio frequency
identification tags are disposed includes a frame, a conveyor that is
disposed moveably on the frame and that conveys items through a path of
travel, each item having at least one respective radio frequency
identification tag disposed thereon. A first antenna is disposed
proximate the path of travel so that the first antenna radiates first
radio frequency signals into a first area through which the items pass. A
second antenna is disposed proximate the path of travel so that the
second antenna receives first responses to the first radio frequency
signals from the respective radio frequency identification tags. The
information identifies a class protocol. A third antenna is disposed
proximate the path of travel downstream from the first antenna and the
second antenna. A fourth antenna is disposed proximate the path of travel
so that the fourth antenna receives second responses to the radio
frequency signals from the respective radio frequency identification
tags. A transmitter drives the first antenna to emit the first radio
frequency signals into the first area and drives the third antenna to
emit second radio frequency signals into a second area. A radio frequency
receiver receives signals from the second antenna corresponding to the
first responses and outputs first output signals corresponding to the
first responses and including the information. The receiver receives
signals from the fourth antenna corresponding to the second responses and
outputs second output signals corresponding to the second responses. A
processor receives the first output signals and controls the transmitter
to drive the third antenna responsively to the first output signals.