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A conventional bar code is a machine readable symbol consisting of a series bars and spaces, with predetermined patterns used to represent actual data in the symbol. Widely implemented in the retail marketplace since the 1970s, bar code technology has continued to demonstrate its flexibility in a broad range of diverse applications.

But what if there was a data capture method that offered many of the advantages of bar code technology, but with even more benefits?

Introducing RFID

Radio Frequency Identification (RFID) works by using tags which can be embedded into labels or other media. A radio signal is transmitted towards the tag, and it responds with a radio signal that contains the information stored in the tag. Because of this, several advantages over bar codes become apparent:

Because the technology uses radio waves, data can be read from tags that are not even optically visible, and physical contact with the tag is not necessary. This is an advantage over traditional bar codes where line of sight and easy access is required for successful capture of the code.

Tags can be preprogrammed with data, or they can allow the data to be "written" in response to commands transmitted to them. This means that tags can be re-used, or the data contained in them can be altered at different stages. Because bar codes are printed onto the media, they are incapable of this kind of re-writing.

RFID tags allow bulk capture. This means that large quantities of tags can be read almost simultaneously, greatly speeding auto-id applications. In contrast, try scanning several bar codes at once!

Example Tags

Why Now? Over the last ten years, Radio Frequency Identification has undergone substantial development. It has always been recognised that RFID offers many advantages over other forms of automatic data capture, but in the past the cost and bulky size of RF tags and readers was prohibitive. Reductions in size and costs have now made RFID more acceptable, and regulators such as EAN, AIM, CEN and ISO have introduced universal standards for the use of this technology. Increasing end-user marketing influence from blue-chip companies is creating awareness and acceptance of RFID. Those using or planning to use RFID include Boots, BBC, Daimler-Chrysler, Warner Brothers, Marks & Spencer, GKN Aerospace and NATO.

How Does It Operate? A basic RFID tag consists of a small chip and an antenna. These components are flat enough to be embedded in a label inconspicuously. There are three key variables which determine how the tag functions; the read/write capabilities, how it is powered, and the operating frequency. Read/Write Capabilities - The tags can be manufactured to be read only (data is set at manufacture, and cannot be changed - inexpensive), WORM (data can only be written once, read many times), or read/write (data can be changed and written repeatedly - most expensive). How it is Powered - Tags can be active or passive. Active tags carry an on-board battery, and are therefore more bulky and expensive. Passive tags have power transmitted to them via inductance coupling, discharged by the reading device, and are less expensive because of this. Operating Frequency - RFID tags can operate at different frequencies for different effects, but a common frequency for these tags is 13.56Mhz. High-frequency systems allow longer ranges and higher data rates, but the costs are also higher. The tags are most commonly embedded into labels, with the information encoded during the print process. Thermal transfer printers are becoming available which will allow printing and encoding in one pass. Current tag manufacturers include Philips and Texas Instruments. Philips market their tags as "I-Code" tags and have a capacity of 44 full ASCII characters. Texas Instruments market them as "Tag-It" and have a capacity of 32 full ASCII characters.

The End of the Barcode? Tags are already being successfully used in many different applications including animal and vehicle ID, car immobilisation, automated payment, security and access control, luggage, parcel and document tracking in many areas such as archives, libraries, and video rental. Tags are particularly suited to warehousing applications where the ability to collect information in bulk is essential. It is expected that more applications will develop as the technology becomes standardised. RFID supports a higher level of automation than most other automatic identification technologies, reducing dependency on people to perform the task of identifying individual items, as with traditional scanning of bar codes. The simple structure of the tags means that it has the robustness to withstand extremely harsh environments, and the concealed nature of the device means more space for packaging design traditionally taken up by bar codes. Does this mean the end of the barcode? Probably not. Bar codes have been in commercial use for almost thirty years and have tremendous support in retail and other industries. The simplicity of bar codes must not be ignored. When a bar code fails to read, the information can be keyed manually by referring to the human readables. Where will the fails-safe be with RFID? The cost of RF tags, although decreasing, will remain prohibitive unless the cost of the tags and reading systems can be justified. It is expected that traditional bar codes will remain dominant until the near future, with 2D bar codes increasing in use as more information is required during transactions. RFID will be adopted where bar codes would not be suitable, such as for bulk capture applications or where there is no line of sight to the product or item. Until RFID has proven itself, to many users bar codes will remain top of the auto-id ladder. Share your opinions on the Labelgraphics Discussion Board!