Ask any analyst about the future of automatic data capture, and you're likely to hear one term: RFID (radio frequency identification).

The technology not only promises to provide access to more real-time information than linear bar codes, but RFID can do something no bar code can: allow you to write live information and update a tag as it moves through the supply chain.

But even as companies like Gillette announce pilot RFID initiatives, broad-based roll-outs are still some time off.

In the meantime, two-dimensional, or 2D, bar codes that carry far more data in a smaller space than linear bar codes are not only available but used by a range of industries.

'We've seen 2D bar codes in the receiving end of the automotive industry and in the food industry where lot tracking is important,' says Peter Morley, a senior product manager for Psion Teklogix (800-322-3437).

Rather than simply identifying a product or location, 2D bar codes are a traveling database that can include a complete history of a product, including lot-tracking information and extended shipping information. Scan a 2D bar code, and it opens right there a complete data file without referencing a lookup file in a distant computer database.

Since many 2D bar codes are read by image-capture devices, you can even encode a low-resolution image or photograph in the symbol.

Also, 2D bar codes have an advantage over linear bar codes: built in error-correction capabilities for reading damaged symbols. 'Redundancy and logic are built in to 2D labels so that when the reader captures the data, it understands that it's damaged and figures out what to fill in,' says Dan Mullen, interim CEO, AIM, the trade group of the auto-identification industry (412-963-8588).

True, you can't write new information to a bar code as it moves through the supply chain without printing a new label. But some applications simply need stable, non-dynamic information.

'When FedEx or UPS ship a parcel, they need to carry the shipping information with them, because they won't always have online access to a database,' says Dick Sorenson, director of product management, LXE (770-447-4224). 'A 2D bar code allows you to imbed that information in the symbol and read it with a scanning device.'

There are literally dozens of 2D bar codes, but a few are more commonly used than others.

A PDF 417 bar code is a laser-scannable symbol that packs up to 1.1 kilobytes of data into the same space as a linear bar code. The printed PDF 417 symbol is capable of carrying data, text, graphics, biometrics and voice records.

The Department of Defense has designated PDF 417 as the standard bar code for supply chain applications. The symbology is also commonly used in the automotive industry. General Motors' standard shipping label includes a PDF 417 label that carries the shipping history of a product. Some states use the symbology on licenses to provide detailed information about drivers to police officers on the spot.

Data Matrix symbols are created from cells of information represented by dark and light squares instead of parallel lines. A two-dimensional image-capture device, like a CCD camera, is necessary to scan a matrix code.

The pharmaceutical industry uses Data Matrix codes for lot tracking purposes, says Dan Bodnar, a director of product marketing at Intermec Technologies (425-348-2799). The consumer electronics industry uses Data Matrix symbols to encrypt model number, serial number, lot information, warranty information, and even product authenticity codes onto products as small as a chip.

MaxiCode uses light and dark hexagonal modules with a bull's-eye finder pattern in the center to store information. MaxiCode is used by UPS, which developed the symbology, to route packages as they travel through the supply chain without having to connect back to the network.

Meanwhile, two other 2D bar codes are beginning to gain attention.

PosiCode is made up of a grid of equally spaced lines. Data is encoded according to where bars are positioned on that grid.

Reduced Space Symbology, or RSS, is designed for applications where the items are too small for current bar codes or where there is a need to capture additional information in a limited space.

While many users think of linear bar codes, 2D symbologies and RFID as competing technologies, the reality is that they complement one another.

For instance, the ISO15394 shipping standard uses a 93-character MaxiCode to provide sortation information; a PDF-417 symbol for shipping, receiving and support documents; and a linear bar code for item-level tracking.

And while some are predicting the death of linear bar codes, it's unlikely.

'There will always be a role because printed bar codes cost 1/100^th of a cent to produce,' says Morley of Psion Teklogix. 'For quick packaging you can't beat the cost.'

In fact, some argue that these new technologies offer an opportunity for a real change in the supply chain. 'RFID and 2D bar codes shouldn't be looked at as just a substitute for linear bar codes,' says Sorenson of LXE. 'We need new business processes that will allow us to create new value with this additional information. Otherwise, we're missing the point.'

Click the icon to learn how the USPS uses high-density bar codes.