
READERS AND PRINTERS 117
configuration, where a host on the network essentially asks the reader to send it any
updates whenever the reader “hears” something. Chapter 6 describes these options in detail.
Readers that support multiple antennas usually support two different ways of using them.
One configuration treats all of the antennas as if they are part of one big antenna and
treats tag reads that come in from any antenna as having come from one logical “source.”
This might be the configuration for a portal, as discussed in the previous section, where we
care that a tag has passed through but not which antenna it was closest to. Another option
is to configure each antenna as if it represents a unique location, a unique source. A good
use of this configuration would be for items passing on a conveyor, where one reader
might monitor antennas at multiple stations. For instance, each antenna might be in its
own tunnel enclosure ...