GS1 EPC Tag Data Standard 1.6 - Indicod-Ecr

2213221422152216221722182219222022212222222322242225222622272228222922302231223222332234223522362237223822392240224122422243224422452246224722482249those specified in Section 14.5. Each column in the coding table corresponds to a bitfield in the input binary encoding. Within each column, a “Coding Method” is specifiedthat says how to calculate a corresponding portion of the output URI, given that bit fieldas input. The decoding details for each “Coding Method” are given in subsections ofSection 14.4.14.2EPC Binary HeadersThe general structure of an EPC Binary Encoding as used on a tag is as a string of bits(i.e., a binary representation), consisting of a fixed length, 8 bit, header followed by aseries of fields whose overall length, structure, and function are determined by the headervalue. For future expansion purpose, a header value of 11111111 is defined, to indicatethat longer header beyond 8 bits is used; this provides for future expansion so that morethan 256 header values may be accommodated by using longer headers. Therefore, thepresent specification provides for up to 255 8-bit headers, plus a currently undeterminednumber of longer headers.Back-compatibility note (non-normative) In a prior version of the Tag Data Standard,the header was of variable length, using a tiered approach in which a zero value in eachtier indicated that the header was drawn from the next longer tier. For the encodingsdefined in the earlier specification, headers were either 2 bits or 8 bits. Given that a zerovalue is reserved to indicate a header in the next longer tier, the 2-bit header had 3possible values (01, 10, and 11, not 00), and the 8-bit header had 63 possible values(recognizing that the first 2 bits must be 00 and 00000000 is reserved to allow headersthat are longer than 8 bits). The 2-bit headers were only used in conjunction with certain64-bit EPC Binary Encodings.In this version of the Tag Data Standard, the tiered header approach has beenabandoned. Also, all 64-bit encodings (including all encodings that used 2-bit headers)have been deprecated, and should not be used in new applications. To facilitate anorderly transition, the portions of header space formerly occupied by 64-bit encodingsare reserved in this version of the Tag Data Standard, with the intention that they bereclaimed after a “sunset date” has passed. After the “sunset date,” tags containing 64-bit EPCs with 2-bit headers and tags with 64-bit headers starting with 00001 will nolonger be properly interpreted.The encoding schemes defined in this version of the EPC Tag Data Standard are shownin Table 16 below. The table also indicates header values that are currently unassigned,as well as header values that have been reserved to allow for an orderly “sunset” of 64-bitencodings defined in prior versions of the EPC Tag Data Standard. These will not beavailable for assignment until after the “sunset date” has passed. The “sunset date” isJuly 1, 2009, as stated by EPCglobal on July 1, 2006.HeaderValue(binary)Header Value(hexadecimal)EncodingLength(bits)0000 0000 00 NA Unprogrammed TagCoding SchemeCopyright ©2005- 2011 GS1 AISBL, All Rights Reserved. Page 80 of 218