GS1 EPC Tag Data Standard 1.6 - Indicod-Ecr

EPCSchemeEPC BinaryCodingSchemeEPC +FilterBitCountIncludesFilterValueSerial Number Limitationgdti-113 113 Yes All values permitted by GS1 GeneralSpecifications (up to 17 decimal digits,with or without leading zeros)gid gid-96 96 No Numeric-only, no leading zeros, decimalvalue must be less than 2 36 (i.e., decimalvalue must be less than or equal to68,719,476,735).usdod usdod-96 96 See “United States Department of DefenseSupplier's Passive RFID Information Guide” thatcan be obtained at the United States Department ofDefense's web site(http://www.dodrfid.org/supplierguide.htm).adi adi-var Variable Yes See Section 14.5.10.1191319141915191619171918191919201921192219231924192519261927192819291930193119321933193419351936193719381939Table 15. EPC Binary Coding Schemes and Their LimitationsExplanation (non-normative): For the SGTIN, SGLN, GRAI, and GIAI EPC schemes, theserial number according to the GS1 General Specifications is a variable length,alphanumeric string. This means that serial number 34, 034, 0034, etc, are alldifferent serial numbers, as are P34, 34P, 0P34, P034, and so forth. In order toprovide for up to 20 alphanumeric characters, 140 bits are required to encode the serialnumber. This is why the “long” binary encodings all have such a large number of bits.Similar considerations apply to the GDTI EPC scheme, except that the GDTI only allowsdigit characters (but still permits leading zeros).In order to accommodate the very common 96-bit RFID tag, additional binary codingschemes are introduced that only require 96 bits. In order to fit within 96 bits, someserial numbers have to be excluded. The 96-bit encodings of SGTIN, SGLN, GRAI, GIAI,and GDTI are limited to serial numbers that consist only of digits, which do not haveleading zeros (unless the serial number consists in its entirety of a single 0 digit), andwhose value when considered as a decimal numeral is less than 2 B , where B is thenumber of bits available in the binary coding scheme. The choice to exclude serialnumbers with leading zeros was an arbitrary design choice at the time the 96-bitencodings were first defined; for example, an alternative would have been to permitleading zeros, at the expense of excluding other serial numbers. But it is impossible toescape the fact that in B bits there can be no more than 2 B different serial numbers.When decoding a “long” binary encoding, it is not permissible to strip off leading zeroswhen the binary encoding includes leading zero characters. Likewise, when encoding anEPC into either the “short” or “long” form, it is not permissible to strip off leading zerosprior to encoding. This means that EPCs whose serial numbers have leading zeros canonly be encoded in the “long” form.In certain applications, it is desirable for the serial number to always contain a specificnumber of characters. Reasons for this may include wanting a predictable length for theCopyright ©2005- 2011 GS1 AISBL, All Rights Reserved. Page 72 of 218