For a basic description and understanding of the structure of the EPC code it would be enough for us to focus on three parts, which are color-illustrated in the following figure by the grey color. Here it can be seen a comparison to a conventional bar code, which is in format GS1-128 for marking common products, and subsequently formed EPC code (96-bit tag).

Corresponding EPC code is further divided by bits:
  • Header – 8 bits
  • Filter – 3 bits
  • Parity – 3 bits

Then there are parts of the GS1 Company Prefix, Object Class and Serial Number. Compared to a bar codes there is not a check digit in EPC.

For the serial number, it is possible to insert additional application identifiers

 

 

EPC

 

EPC code header

The main structure of the binary encoding of EPC is made up of a string of bits, which consists of a header (fixed length of 8 bits) and subsequently from several fields whose total length, structure and function is indicated by the value of fixed header field. For future header extension, it uses the value 11111111, which thus prescribes that the header with more length than 8 bits is used. Each header field values are shown in the following table.

 

Header value

Header value

Code length

Scheme

(binary)

(hexadecimally)

(bit)

0000 0000

00

NA

Unprogrammed Tag

0000 0001

01

NA

Reserved for future use

0000 001x

02,03

Reserved for future use

0000 01xx

04,05

NA

Reserved for future use

 

06,07

NA

Reserved for future use

0000 1000

08

64

Reserved for the life of 64 bit <SSCC-64>

0000 1001

09

64

Reserved for the life of 64 bit <SGLN-64>

0000 1010

0A

64

Reserved for the life of 64 bit <GRAI-64>

0000 1011

0B

64

Reserved for the life of 64 bit <GIAI-64>

0000 1100

0C

 

Reserved for the life of 64 bit

to

to

 

0000 1111

0F

 

0001 0000

10

NA

Reserved for future use

to

to

NA

0010 1011

2B

 

0010 1100

2C

96

GDTI-96

0010 1101

2D

96

GSRN-96

0010 1110

2E

NA

Reserved for future use

0010 1111

2F

96

USDoD-96

0011 0000

30

96

SGTIN-96

0011 0001

31

96

SSCC-96

0011 0010

32

96

SGLN-96

0011 0011

33

96

GRAI-96

0011 0100

34

96

GIAI-96

0011 0101

35

96

GID-96

0011 0110

36

198

SGTIN-198

0011 0111

37

170

GRAI-170

0011 1000

38

202

GIAI-202

0011 1001

39

195

SGLN-195

0011 1010

3A

113

GDTI-113

0011 1011

3B

Variable

ADI-var

0011 1100

3C

96

CPI-96

0011 1101

3D

Variable

CPI-var

0011 1110

3E

 

Reserved for future header value

to

to

 

0011 1111

3F

NA

0100 0000

40

 

Reserved for the life of 64 bit

to

to

 

0111 1111

7F

 

1000 0000

80

 

Reserved for the life of 64 bit <SGTIN-64>

to

to

 

1011 1111

BF

64

1100 0000

C0

 

Reserved for the life of 64 bit

to

to

 

1100 1101

CD

 

1100 1110

CE

64

Reserved for the life of 64 bit <DoD-64>

1100 1111

CF

 

Reserved for the life of 64 bit

to

to

 

1111 1110

FE

 

1111 1111

FF

NA

Reserved for future header value larger than 8 bits

 

Example of using the header

Means of identification will be introduced on the example of full loaded pallet identification. Relevant products will be packed in boxes by six pieces in each box, whereas on one entire pallet can be loaded 5 boxes. Then there are 30 pieces of goods in total packed on a pallet. The following description shows the way of packed levels hierarchy identification.

 

značení

Examples of products identification

 

  • Point of Sale (POS) / Trade Item= SGTIN  96 --> Binary value 0011 0000 = Hexadecimal value value 30,
  • box = SGTIN 96 --> Binary value 0011 0000 = Hexadecimal value 30,
  • Pallet = SSCC 96 --> Binary value 0011 0001 = Hexadecimal value 31.

 

Product type

Standard used

Binary value

Hexadecimal value

Point of Sale (POS) / Trade Item

SGTIN 96

0011 0000

30

Box

SGTIN 96

0011 0000

30

Pallet

SSCC 96

0011 0001

31

 

In the context of tag it is a EPC/UHF RFID tag 96 bit.

 

EPC code filter

In case of filter it is an additional controlling value which may be a part of the memory of the EPC Gen 2 tags. Its purpose is to allow the RFID readers to select or not to select relevant tags during reading based on the type of their physical representation. The aim of the filter is to make reading tags easier, especially in an environment where are located more of them. An example is reading tag which identify pallet of goods, where the presence of item tags packed on the pallet are expected, there it can be even hundreds of them. Read performance can then be increased by selectively choosing items based on the value of the filter.

 

It is important to remember that the filter serves as an additional control information and it is not a part of the EPC code. The filter is therefore not contribute to the uniqueness of the EPC identifier. For example, using of two RFID tags on two physically different objects, where both EPC tags contain the same code and only the filter value would be different is unacceptable.

 

 

Filter “Reserved” and “All others”

 

The values of the field Filter labeled “Reserved” are reserved for future assignment within the specification of EPCglobal. Implementation of coding and decoding rules should accept any value in the Filter field, as it is labelled as “Reserved” or not. Application should however not to write nor read the Filter value labeled as “Reserved”, which can cause problems with interoperability, if the “Reserved” value will be assigned in future version of this specification.

 

EPC scheme also includes a filter value designated as the “All Others”. This value says that the article marked by the tag does not match any other description of predefined values from the Filter field within the EPC scheme. There are cases, when the Filter field contains the value “All Others” because the tags were encoded in compliance with an earlier specification of EPC, where the corresponding value of the Filter field for the item was not defined previously. In the case of writing the new tag, the Filter field should contain a value that would match the description of the object type, and the value “All Others” should be used only when the EPC specifications does not contain the appropriate value for the type of object.

 

Filters for EPC tags

Filters for EPC tags SGTIN

Type

Filter

Binary

 

Value

Value

 
 

All Others

0

000

 

Point of Sale (POS) Trade Item

1

001

 

Full Case for Transport

2

010

 

Reserved

3

111

 

Logistic unit designed for internal manipulation

4

100

 

Reserved

5

101

 

Unit Load

6

110

 

Unit inside Trade Item or component inside a product not intended for individual sale.

7

111

 

 Filters for EPC tags SSCC

Type

Filter

Binary

 

Value

Value

 
 

All Others

0

0

 

Reserved

1

1

 

Full Case for Transport

2

10

 

Reserved

3

11

 

Reserved

4

100

 

Reserved

5

101

 

Reserved

7

111

 

Filters for EPC tags GRAI

Type

Filter

Binary

 

Value

Value

 
 

All Others

0

0

 

Reserved

1

1

 

Reserved

2

10

 

Reserved

3

11

 

Reserved

4

100

 

Reserved

5

101

 

Reserved

6

110

 

Reserved

7

111

 

Filters for EPC tags ADI

Type

Filter

Binary

 

Value

Value

 
 

All Others

0

000000

 

All Others than filters 8 to 63

     

All Others than filters 8

1

1

 

through 63 apply)

     

Carton

2

000010

 

Reserved

3 do 5

000011 do 000101

 

Pallet

6

000110

 

Reserved

7

000111

 

Seat cushions

8

001000

 

Seat covers

9

001001

 

Seat belts

10

001010

 

Galley cars

11

001011

 

Unit Load Devices, cargo containers

12

001100

 

Security items - life vest boxes, rear lav walls, lav ceiling access hatches

13

001101

 

Life vests

14

001110

 

Oxygen generators

15

001111

 

Engine components

16

010000

 

Avionics

17

010001

 

Experimental (“flight test”) equipment

18

010010

 

Other emergency equipment (smoke masks, PBE, crash axes, medical kits, smoke detektors, flashlighting, etc.)

19

010011

 

Other rotables; e.g., line or base replaceable

20

010100

 

Other repairable

21

010101

 

Other cabin interior

22

010110

 

Other repair (exclude component); e.g., structure item repair

23

010111

 

Reserved

24

011000 do 111111