Passive systems can have a read range of about 10 meters (30 feet), while an active system can be in the hundreds of meters.

David: Can these RFID tags that are radiating cause interference with other systems?

Martyn: Yes. This is why it is important to set up your RFID reader network correctly to minimize the interference the RFID readers might have on other systems like WiFi networks, paging networks, mobile phones, etc., but also to minimize the affect of those systems on RFID.

For example, you might use proximity sensors to turn on RFID readers only when the packages enter through the dock door so that the reader is only reading (and emitting RF) when required.

David: Are tags on all the time?

Martyn: In a passive RFID system, the tags don't have a power source, so they are only "on" when a reader is trying to read them -- they get their power from the RFID reader's antenna.

For Active RFID, some tags are always on, emitting a signal periodically. Others (sometimes called semi-active) hibernate until woken up by a reader; then they power up and emit their signals for a defined period of time.

This saves battery life so that the tag is only using power when there is a reader present. This is the technology used by many highway toll systems.

David: So RFID is not just about automating shopping checkout?

Martyn: By no means is that true, as RFID is being used in many industries, including supply chain and retail, but also healthcare, logistics, manufacturing, asset location tracking, access control, automated payment systems and so on.

However, the shopping cart scenario does get people thinking about some of the benefits of RFID on top of typical barcodes or other ways that items are tracked or identified today.

David: Isn't RFID just a barcode on steroids?

Martyn: Some look at RFID that way, but that viewpoint minimizes the abilities of what RFID can offer. While barcodes and RFID do share some of the same advantages, such as improved data accuracy by collecting data at point of activity and reducing the cost and errors of manual data capture, RFID offers a number of unique advantages.

RFID doesn't require line of sight. For example, you don't have to break down a pallet of boxes just to "scan" the tag on the box in the middle of the pile.

RFID performs in rugged environments. For example, you can have RFID tags encased in plastic or glass to protect them from weather, dirt, etc. whereas some printed barcodes could easily get dirty or worn off, making them unreadable.

Some RFID tags can be rewritten so you can change the data on the microchip. You obviously can't change a printed barcode on a metal can or product box.

You can read multiple RFID tags at once. Makes it easier and faster to read a pallet of goods, shopping cart of items, warehouse of products, etc.

And, most importantly, RFID tags are unique to one another. This means that individual items can be identified even when all items of a certain type have the same barcode.

We've got a lot more coming on the topic of RFID. Martyn will be back next week, where we continue our in-depth Q&A.

Jet Kaehn is a busy administrative assistant who lives in Chicago.