Serialization Roadmap

A top-level tagging plan will help apparel suppliers identify items now, and pave the way for tracking more products in the future.
Published: June 25, 2012

A growing number of apparel retailers are adopting item-level RFID to manage their inventory, which means more apparel suppliers will be asked to tag goods at the point of manufacture. My November/December 2011 column, “Identifying Items,” discussed four ways apparel suppliers can assign a unique serial number to each item they want to track, using a passive ultrahigh-frequency RFID tag—a process called “serialization.”

A supplier that manufactures each clothing product on a single manufacturing line can choose any one of the four options. But many suppliers manufacture in several plants or use third-party service providers. To avoid duplicating serial numbers—whether you choose one serialization method or a combination of all four—you need what GS1 US calls a “top-level serialization plan.”

A top-level serialization plan is a written statement identifying the method that will be used to assign serial numbers for a given product, as well as the range of numbers. If the supplier will be using more than one method, the plan assigns a different range of serial numbers to each method, so the numbers will never be duplicated.

Let’s say, for example, Supplier X does most of its tagging on in-house manufacturing lines, but supplements with a service bureau when demand is high. Supplier X writes a plan that says products tagged in-house will be assigned numbers one at a time, and the range of serial numbers will be 0 through 137 billion—half the available range in 96-bit tags. The plan assigns the service bureau a smaller range of serial numbers, 138 billion through 206 billion. In addition to avoiding duplication of numbers, the plan provides a common point of reference for all parties concerned.

Supplier Y, on the other hand, would like to use the unique “tag identifier” (TID) serial number burned into RFID tags by the tag manufacturer to track items. But Supplier Y wants the freedom to use tags from different manufacturers, as well as retain the option to assign its own serial numbers down the road. Supplier Y writes a plan that creates eight ranges of serial numbers, allocating some ranges for TIDs and reserving the other ranges for the future. Supplier Y must work with each chip maker to avoid duplicating serial numbers. In March, three leading RFID companies announced a coordinated method to assigning serial numbers (see Three RFID Chip Makers Agree on Serialization Approach). If this approach meets Supplier Y’s business needs, it could be adopted as a ready-made plan.

These are just two examples of top-level serialization plans. GS1 US has published a guide titled “EPC-enabled RFID Serialization Management” that explains all four options in detail, as well as how to create a plan (see RFID News Roundup: GS1 US Publishes RFID Tag-serialization Guidelines). Each apparel supplier has the flexibility to develop its own plan. The point is: You need a plan.

Ken Traub is the founder of Ken Traub Consulting, a Mass.-based firm providing services to software product companies and enterprises that rely on advanced software technology to run their businesses.