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EAN-8 SYMBOLOGY

See Also:   UPC-A    EAN-13    UPC-E    Bookland    UPC 2-Digit Supplement    UPC 5-Digit Supplement    Symbology Index



Quick Links:   Background    Encoding    Parity Table    Structure    Example


UPC-E BACKGROUND INFORMATION

EAN-8 is the EAN equivalent of
UPC-E in the sense that it provides a "short" bar code for small packages. As can be seen in the following graphic, an EAN-8 bar code is shorter than an EAN-13 bar code, although somewhat longer than an UPC-E bar code.


    NOTE: The three bar codes above are shown only for relative size comparison. The three bar codes do not necessarily represent the same product, nor do they represent equivalent values.

The similarities end there, however. Unlike UPC-E in which only 6 digits are explicitly encoded, EAN-13 explicitly encodes all eight digits; the parity of the digits carries no particular significance. This means that although EAN-13 is compatible with UPC-A, EAN-8 has absolutely no compatability with UPC-E.

Another difference between UPC-E and EAN-13 is that UPC-E has a direct UPC-A equivalence--a UPC-E bar code may be "expanded" back to UPC-A. This is not the case with EAN-8. An EAN-8 bar code is a 2- or 3-digit number system code followed by a 4- or 5-digit product code. The EAN-8 product codes are assigned directly by the numbering authority. This has the advantage that any company can request an EAN-8 code regardless of its EAN-13 manufacturer or product code. It has the disadvantage that the EAN-8 codes must be stored in each database as a separate product since there is no way to translate an EAN-8 code to an EAN-13 equivalent.

ENCODING

EAN-8 is encoded using the three EAN-13 character sets. EAN-8 also has a check digit that is calculated in the same way as EAN-13. Assuming we wish to encode the 7-digit message "5512345", we would calculate the checksum in the following manner:

    Barcode 5 5 1 2 3 4 5
    Position O E O E O E O
    Weighting 3 1 3 1 3 1 3
    Calculation 5 * 3 5 * 1 1 * 3 2 * 1 3 * 3 4 * 1 5 * 3
    Weighted Sum 15 5 3 2 9 4 15
The total is 15 + 5 + 3 + 2 + 9 + 4 + 15 = 53. 7 must be added to 53 to produce a number evenly divisible by 10, thus the checksum digit is 7 and the completed bar code value is "55123457".

STRUCTURE

An EAN-8 bar code has the following physical structure:

  1. Left-hand guard bars, or start sentinel, encoded as 101.
  2. Two number system characters, encoded as left-hand odd-parity characters.
  3. First two message characters, encoded as left-hand odd-parity characters.
  4. Center guard bars, encoded as 01010.
  5. Last three message characters, encoded as right-hand characters.
  6. Check digit, encoded as right-hand character.
  7. Right-hand guar bars, or end sentinel, encoded as 101.

ENCODING EXAMPLE

Encoding the data "55123457" (the trailing "7" is the check digit), we obtain the following:

  1. LEFT GUARD BARS (always the same): 101.
  2. 1st EAN-8 NUMBER SYSTEM DIGIT [5]. Encoding with left-hand odd parity, 0110001.
  3. 2nd EAN-8 NUMBER SYSTEM DIGIT [5]. Encoded with left-hand odd parity, 0110001.
  4. 1st EAN-8 DATA DIGIT [1]. Encoded with left-hand odd parity, 0011001.
  5. 2nd EAN-8 DATA DIGIT [2]. Encoded with left-hand odd parity, 0010011.
  6. CENTAR GUARD BARS (always the same): 01010.
  7. 3rd EAN-8 DATA DIGIT [3]: Encoded as right-hand character, 1000010.
  8. 4th EAN-8 DATA DIGIT [4]: Encoded as right-hand character, 1011100.
  9. 5th EAN-8 DATA DIGIT [5]: Encoded as right-hand character, 1001110.
  10. CHECK DIGIT [7]: Encoded as right-hand character, 1000100.
  11. RIGHT GUARD BAR (always the same): 101.
In order to see more clearly the construction of the bar code, the following graphic shows the exact same bar code but each character, or section, of the bar code is indicated by alternating colors. Above the bar code, in each colored section, is a number from 1 to 11, which corresponds to each of the "steps," or sections, described above. You may easily compare the 1-0 sequence of each step to the graphical representation below:



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