Construct 1 and Construct 2 IUID (Item Unique Identifier Data) Nameplates
Construct 1 and Construct 2 IUID (Item Unique Identifier Data) Nameplates

It is easy for aerospace buyers, purchasing managers, and planners to succumb to the alphabet soup of acronyms and ideas used in the IUID/UID government policies. Jet City Laser answers many of the most frequently asked questions about the IUID program in this IUID guide.

What is so Important about the US Government’s Program Called IUID?

iuid item unique traceability logoThink of IUID as an asset and data management tool on a global scale. It is an effort by the United States and other NATO government agencies to understand the type, location, cost, and availability of hardware and physical assets they own all over the world.

The machine-readable IUID marks enable quick and precise automatic data capture for program management, engineering, and accountability.

Using IUID marks enables government agencies to distinguish one item from another throughout the usable life of the item being traced.

What is the Difference Between IUID and UID?

iuid aadhaar with strike thru uadi govUID (Unique Identification) and IUID (Item Unique Identification) are interchangeable descriptions for a government policy that started with the Joint Total Asset Visibility Strategic Plan that was launched in January 1999 by the Joint Total Asset Visibility Office at the Department of Defense (DoD).

The program originally was called UID (Unique Identification). The UID acronym needed to be officially changed because it was so easily confused with the Government of India’s identification card program for Indian citizens, called AADHAAR ‘UID’ for Unique Identification.

Another reason to push for the change from UID to IUID existed closer to home. The armed forces and government agencies noted the similarities among UID, IUD, and IED.

What is UII?

The Unique Item Identifier (UII) is the set of data encoded into a Data Matrix symbol that is so unique that it identifies only this one particular item.

The UII is encoded into a Data Matrix symbol with a software program that uses a very specific language. It’s laid out with a mandated sentence structure that a computer can identify and interpret anywhere it is read.

JCL Construct with UII Data

What Attributes Do the 2D Data Matrix Code Contribute to UII?

A 2d data matrix can encode a significant amount of data and incorporate a robust Error Correction Code (ECC). A single square or rectangular 2d code can handle up to 2,335 alphanumeric characters – equivalent to two pages of typed, single-spaced text.

There are several advantages to using 2d data matrix technology versus a standard linear 1d barcode:

  • 2d codes contain 100 times the data as the same space of a linear barcode
  • 2d codes can be read omnidirectionally
  • 2d codes can be damaged but still return accurate data thanks to ECC
  • 2d codes can be scaled up or down to fit within the available marking space. The symbol, a square or rectangular, can range in size from 0.001 inches per side up to 14 inches per side.

What Does ECC Mean For a 2D Data Matrix Code?



Digital error correction codes (ECC) are used routinely in computer-generated data activities like satellite communications, digital TV, CDs and DVDs, RFID, 2d codes, and QR codes. Digital error correction keeps your digital audio files from becoming white noise. Error-correcting codes embedded in the 2d matrix keep IUID 2d codes readable in the field year after year.

The preferred IUID symbology used for the marking on an item is a 2-dimensional (2d) data matrix symbol using Error Correction Code (ECC) 200. Error correction codes are clever human-designed digital algorithms that eliminate distortion problems with digital data and can even restore data when a part of the code is damaged or missing.

ECC 200 is one of the newest versions. It can be distinguished from older versions because it has an even number of squares (known as modules) per side.

Can 1D Codes be Used with IUID?

Yes, certain IUID constructs allow 1d codes. By design, 1d linear barcodes are limited in the amount of data that can be coded within them.

They can also be used in the catch-all category called a ‘DoD recognized IUID equivalent’.

JCL 1d Code Used in IUID

What is a Construct?

A data construct is a standardized information layout. The term comes from the phrase ‘Constructed Item Unique Identification’. The rules are laid out in MIL-STD-130 and DFARS 252.211-7003.

The Department of Defense (DoD) requires its suppliers and their subcontractors to select both a data construct and an encoding format for their UID numbering system.

The two most common types of item unique serialization construction layouts approved by the DoD are Construct #1 and Construct #2.

How To Determine Whether to Use the Construct 1 or the Construct 2 Layout

The UII data can be ‘constructed’ in one of many formats; the most common formats are UII Construct #1 and UII Construct #2.

The key to determining whether to use UII layout Construct 1 or Construct 2 layout lies in how a company serializes item numbers.

Based on the current enterprise configurations

  • If items are serialized within the enterprise, use Construct #1
  • If items are serialized within the part, lot, or batch number, use Construct #2

Formatting the UII Data for Construct #1 and Construct #2

The Unique Item Identifier (UII) is the set of data encoded into a data matrix symbol. The UII is so unique that it identifies only one particular item.

Every UII construct includes the following three data points:

  1. Issuing agency code
  2. Enterprise ID
  3. Unique serial number

The UII data is derived by concatenating the data elements in the following order.

  • UII Construct #1 data layout (in the order listed): issuing agency code, enterprise ID, serial number
  • UII Construct #2 data layout (in the order listed): issuing agency code, enterprise ID, followed by either a) original part number then serial number OR b) latest batch number and serial number

UII Construct #1 Example (serialization within the enterprise identifier)

Construct 1 IUID Nameplate JCL

Use Construct #1 when the company providing the item serializes unique items (rather than serializing by part number, lot, or batch). Serialization is sequential and defined by the number of unique items issued or produced. This unique item identification (UII) is achieved by combining the issuing agency code, the enterprise identifier (EID), and the serial number, which must be itself be unique within the enterprise identifier.


CONSTRUCT #1 FORMATS are identifiable by two separate 2d matrix codes on the nameplate.

Two UII Construct #2 Examples (serialization within the original part, lot, or batch number)

Two UII Construct #2 Examples (serialization within the original part, lot, or batch number)

Use Construct #2 when the business or government activity that controls the production of the item uses serialization within the original part, lot, or batch number.


CONSTRUCT #2 FORMATS are identifiable by one 2d Data Matrix code on the nameplate.

Speak with the IUID Label and Nameplate Specialists

Jet City Laser is the go-to business for all types of IUID nameplate, label, and direct part marking services. We make sense of the alphabet soup of acronyms and ideas used in the IUID/UID government policies.

Contact us online or call (206) 623-4949 today to speak with a government compliance label and nameplate specialist.


DPC Defense Pricing and Contracting, Defense Acquisition Regulations System (DARS) – 252.211-7003 Item Unique Identification and Valuation.

Defense Pricing & Contracting, Assistant Secretary of Defense (Acquisition) – Data Standards – Item Unique Identification (IUID)

What is a DataMatrix code? https://www.keyence.com/ss/products/auto_id/codereader/basic_2d/datamatrix.jsp

Unique Identification Authority of India, Government of India https://www.uidai.gov.in/

Jet City Laser – IUID Labels and Nameplates – https://www.uid2go.com/iuid-labels/