ISO IEC 16023 pdf download – Information technology — International symbology specification — MaxiCode

ISO IEC 16023 pdf download – Information technology — International symbology specification — MaxiCode
4.4.4.3 Lock-In Character
A Lock-In Character, following a Shift Character forthe same Code Set has the effect of behaving as a Latch Character. The Code Set remains in effectuntil a Latch Character is invoked.
4.4.4.4Double Shift Characters
A Double Shift Character (referred to as [2 Shift A]is used to switch from Code Set B to Code Set A forthe next two characters following the [2 Shift A]
Character. Subsequent characters shall revert toCode Set B.
4.4.4.5Triple Shift Character
A Triple Shift Character [3 shift A] is used to switchfrom Code Set B to Code Set A for the next three
characters following the [3 Shift A] Character.Subsequent characters shall revert to Code Set B.
4.4.4.6 Numeric Shift
Numeric Shift allows 9 digit strings to be encodedinto 6 codewords. A Numeric Shift Character [NS]indicates that the next five codewords, equivalent to30 bits, encodes 9 numeric digits in binary format.
Subsequent character encodation shall revert to theCode Set defined prior to the Numeric Shift Character. For longer numeric strings it is possible
to mix numeric compaction using Numeric Shift(s)and conventional encodation. Annexe F provides more detailed advice about Numeric Shift for anylength of digit string.
4.4.4.7 Extended Channel Interpretation Character
An Extended Channel Interpretation (ECI) characteris used to change from the default interpretation used to encode data. The Extended Channel
Interpretation protocol is common across a number
of symbologies and is defined more fully in Section4.6.
The ECI character shall be followed by one, two,three, or four codewords which identify the ECI
being invoked. The new ECI remains in place untilthe end of the encoded data, or until another ECI
character is used to invoke another interpretation.
4.4.4.8 Pad Character
The Pad character in the first position is used forstructured append (see Section 4.9)y; otherwise it isused to fill out remaining data capacity of the
symbol.
4.5 User Considerations for Encoding Data in a MaxiCode Symbol A MaxiCode symbol has a fixed number of modules and codewords. The 144 codewords can be used to encode the mode, data, symbology control functions, and error correction. It is also possible to use structured append to combine up to eight MaxiCode symbols. A number of symbology parameters may be pre-determined by the application. These include the level of error correction and the mode. Other parameters are more associated with the data, including the use of particular character sets, the need for data to conform to particular application standards or message syntax (e.g. EDIFACT), and the degree of switching between Code Sets. MaxiCode encodation should be done automatically, but some general guidelines on the capacity of a symbol to encode data are given in Section 4.5.5 and Annexe G.
4.5.1 User Selection of Error Correction Level MaxiCode symbols offer two levels of error correction (which are specified in Section 4.10). In an application it is sufficient to understand that these two levels require different numbers of codewords, offer different levels of error recovery and are selected by the choice of mode. The basic features are set out in Table 2.