SGTIN¶

class epc.schemes.SGTIN(*args, **kwargs)¶

The Serialised Global Trade Item Number EPC scheme is used to assign a unique identity to an instance of a trade item, such as a specific instance of a product or SKU.

General syntax: urn:epc:id:sgtin:CompanyPrefix.ItemRefAndIndicator.SerialNumber

Example: urn:epc:id:sgtin:0614141.112345.400

filter(tag_filter)¶

The filter value is additional control information that may be included in the EPC memory bank of a Gen 2 tag. The intended use of the filter value is to allow an RFID reader to select or deselect the tags corresponding to certain physical objects, to make it easier to read the desired tags in an environment where there may be other tags present in the environment. For example, if the goal is to read the single tag on a pallet, and it is expected that there may be hundreds or thousands of item-level tags present, the performance of the capturing application may be improved by using the Gen 2 air interface to select the pallet tag and deselect the item-level tags.

Allowed values for SGTIN tags:

Value	Constant	Description
0	FILTER_ALL	All Others
1	FILTER_POS	Point of Sale Trade Item
2	FILTER_FULL_CASE	Full Case for Transport
3	FILTER_RESERVED_3	Reserved
4	FILTER_INNER_PACK	Inner Pack Trade Item
5	FILTER_RESERVED_5	Reserved
6	FILTER_UNIT_LOAD	Unit Load
7	FILTER_INNER_ITEM	Unit Inside Trade Item

Parameters: tag_filter (int) – The filter value, defaults to FILTER_ALL.
Raises: AttributeError – Filter must be between 0 and 7.
Returns: The SGTIN tag object.
Return type: epc.schemes.SGTIN

company_prefix(company_prefix, company_prefix_length=None)¶

The GS1 Company Prefix, assigned by GS1 to a managing entity.

Length corresponds to the number of digits in the company prefix.

Parameters

company_prefix (str, int) – GS1 company prefix.
company_prefix_length (int, optional) – Number of digits in the company prefix. Required when company_prefix is an int.

Returns

The SGTIN tag object.

Return type

epc.schemes.SGTIN

item_reference(item_reference)¶

The Item Reference is assigned by the managing entity to a particular object class.

The Item Reference as it appears in the EPC URI is derived from the GTIN by concatenating the Indicator Digit of the GTIN (or a zero pad character, if the EPC URI is derived from a GTIN-8, GTIN-12, or GTIN-13) and the Item Reference digits, and treating the result as a single numeric string.

Parameters: item_reference (int, str) – The item reference.
Raises: ValueError – item_reference must be an integer
Returns: The SGTIN tag object.
Return type: epc.schemes.SGTIN

serial_number(serial_number)¶

The Serial Number, assigned by the managing entity to an individual object. The serial number is not part of the GTIN, but is formally a part of the SGTIN.

Parameters

serial_number (str, int) – The serial number.

Raises

AttributeError – Serial number bit length incorrect.
AttributeError – Serial number length incorrect.

Returns

The SGTIN tag object.

Return type

epc.schemes.SGTIN

tag_size()¶

Set the size for the tag. Options are SIZE_96 or SIZE_198.

Parameters: tag_size (int) – Tag size in bits. Defaults to SIZE_96.
Raises: AttributeError – Invalid tag size specified.
Returns: The SGTIN tag object.
Return type: epc.schemes.SGTIN

property tag_uri¶

Returns: The tag’s URI.
Return type: str

property pure_identity_uri¶

Returns: The tag’s pure identity URI.
Return type: str

property barcode¶

Returns: The barcode representation of the tag.
Return type: str

property barcode_humanized¶

Returns: A human readable barcode representation of the tag.
Return type: str

property gtin¶

A Global Trade Item Number (GTIN) is the 14 digit GS1 Identification Key used to identify products. The key comprises a GS1 Company Prefix followed by an Item Reference Number and a Check Digit.

Returns: The GTIN-14 representation of the tag.
Return type: str

property values¶

Returns

Dictionary containing:

size (int): the tag’s size in bits
filter (int)
company_prefix (str)
item_reference (int)
serial_number (int or str)

decode_epc(hex_string)¶

Decode an encoded tag and populate this object’s values from it.

Parameters

hex_string (str) – Tag data encoded as a hexadecimal string.

Raises

ValueError – EPC scheme header does not match input.
ValueError – Filter does not match allowed values.
ValueError – Supplied hex_string bit length invalid.

decode_barcode(barcode, company_prefix_length)¶

Decode a barcode and populate this object’s values from it.

Parameters

hex_string (str) – Barcode
company_prefix_length (int) – Number of digits of the company prefix length

Raises

ValueError – Expected barcode header does not match input
AttributeError – Invalid check digit
AttributeError – Invalid barcode length, or wrong company prefix
AttributeError – Invalid item_reference in barcode

decode_gtin(gtin, company_prefix_length, serial_number=0)¶

Decode a GTIN (Supports GTIN-14, GTIN-13, GTIN-12 formats) to populate this object’s values from it. Check digit must be included.

Parameters

gtin (str) – Global trade item number
company_prefix_length (int) – Number of digits of the company prefix length
serial_number (int, str, optional) – Serial number to set on the tag. Defaults to 0.

Raises

ValueError – Invalid GTIN length
AttributeError – Invalid check digit
AttributeError – Invalid company_prefix_length specified
AttributeError – Invalid item_reference in gtin

check_fields()¶

Checks to make sure all components of the tag are present, including size, filter, company_prefix, item_reference and serial_number.

Raises: AttributeError – If any components of the tag are missing.

Hint

To get the encoded tag data, use python’s built in conversion methods:

>>> tag = SGTIN().tag_size(SGTIN.SIZE_198)
>>> tag.company_prefix('000123').item_reference(18).serial_number('ABC')

# Hexadecimal
>>> hex(tag)
'0x3618001ec00004a0c28600000000000000000000000000000000'

# Binary
>>> bin(tag)
'0b11011000011000000000000001111011000000000000000000010010100000110000101000011000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000'

Constants¶

Filters

SGTIN.FILTER_ALL¶

SGTIN.FILTER_POS¶

SGTIN.FILTER_FULL_CASE¶

SGTIN.FILTER_RESERVED_3¶

SGTIN.FILTER_INNER_PACK¶

SGTIN.FILTER_RESERVED_5¶

SGTIN.FILTER_UNIT_LOAD¶

SGTIN.FILTER_INNER_ITEM¶

Sizes

SGTIN.SIZE_96¶: 96 bit tag size.

SGTIN.SIZE_198¶: 198 bit tag size.

Headers

SGTIN.HEADER_BARCODE¶: GS1 specified GTIN barcode header: 01.

SGTIN.HEADER_BARCODE_SERIAL_NUMBER¶: GS1 specified GTIN serial barcode header: 21.

SGTIN.HEADER_96¶: GS1 specified hexadecimal header for 96 bit SGTIN tags: 0x30.

SGTIN.HEADER_198¶: GS1 specified hexadecimal header for 202 bit SGTIN tags: 0x36.

SGTIN.SGTIN_96¶: Human readable GS1 specified header for 96 bit SGTIN tags: sgtin-96.

SGTIN.SGTIN_198¶: Human readable GS1 specified header for 198 bit SGTIN tags: sgtin-198.