David: Back in the day, we were all about barcodes. Are barcodes obsolete in an RFID world?

Martyn: RFID and barcodes are used together in many systems. RFID may be used for one component of a system, while a barcode is used for some existing components of the application or perhaps used by a partner who hasn't implemented RFID in its environment.

David: Where do PLCs fit into this?

Martyn: Programmable Logic Controllers are hardware devices programmed to control sensors, feedback mechanisms, heating/cooling systems, etc., and are often used with RFID, or integrated into a system using the same event-driven API.

David: As you know, our readers are mobile gadget aficionados. What sort of mobile devices work with RFID?

Martyn: Handheld RFID readers and barcode scanners introduce their own unique strengths and complexities, but are part of many RFID deployments where you can't always take the asset to the reader, for example, taking inventory of a warehouse.

David: You've mentioned Active RFID. Where does that fit in?

Martyn: Battery-powered RFID using a variety of communication methods provides longer range than passive RFID -- useful for systems where you might be tracking goods over a longer range. Some examples are livestock within a field, used cars within a large lot, equipment in a large warehouse.

David: I've also read about RFID and real time location systems. What's that about?

Martyn: These systems typically leverage WiFi networks and specialized tags to track the exact X,Y position of valuable goods using triangulation. Here, the data isn't just "I saw this tag," the data is "This tag is at position X,Y".

Infrastructure is used for mapping and alert/report generation, and with RFID Anywhere's Location Information System, both RTLS and RFID can be used in the same system (and even represented on the same map).

David: How do you network this stuff, when it's not connected all the time? Is there some technology that manages "occasional" connections?

Martyn: Distributed environments are very popular for RFID deployments since you often need to react to the RFID data immediately at the point of activity. Here, you would have RFID Anywhere and business logic running at the point of activity (or the "edge") handling data as it comes in.

Then, if you have data that needs to be reported to a system further up the network, you can use any number of technologies -- database storage and synchronization, message queuing, Web services -- to integrate it when a network connection is available.

However, the important element is having business logic and intelligence right near the reader to act on the RFID data immediately without requiring a constant connection to a central server.

David: Earlier, we talked about vendor privacy issues. RFID is a communications system, so can you speak on the security infrastructure of RFID?

Martyn: RFID security encompasses all layers of your RFID network. For each layer there are efforts to provide the utmost in security. Let's go through each, in turn.