Auxiliary information to allow a printing application to use
the channel for data submission to the printer. An application
capable of using a specific PrtChannelType should be able to
use the combined information from the prtChannelInformation and
other channel and interface group objects to 'bootstrap' its
use of the channel. prtChannelInformation is not intended to
provide a general channel description, nor to provide
information that is available once the channel is in use. The
encoding and interpretation of the prtChannelInformation object
is specific to channel type. The description of each
prtChannelType enum value for which prtChannelInformation is
defined specifies the appropriate encoding and interpretation,
including interaction with other objects. For channel types
that do not specify a prtChannelInformation value, its value
shall be null (0 length). When a new prtChannelType enumeration
value is registered, its accompanying description must specify
the encoding and interpretation of the prtChannelInformation
value for the channel type. prtChannelInformation semantics for
an existing PrtChannelType may be added or amended in the same
manner as described in section 2.4.1 for type 2 enumeration
values. The prtChannelInformation specifies values for a
collection of channel attributes, represented as text according
to the following rules:
1. The prtChannelInformation is coded in the NVT ASCII
character set. It is not affected by localization.
2. The prtChannelInformation is a list of entries
representing the attribute values. Each entry consists
of the following items, in order:
a. a keyword, composed of alphabetic characters (A-Z, a-z),
that identifies a channel attribute,
b. an Equals Sign (=) to delimit the keyword,
c. a data value, consisting of NVT ASCII graphics
characters (codes 32-126),
d. a Line Feed character (code 10) to delimit the data
value.
No other characters shall be present. Keywords are
case-sensitive. Conventionally, keywords are
capitalized (including each word of a multi-word
keyword), and, since they occupy space in the
prtChannelInformation, they are kept short.
3. If a channel attribute has multiple values, it is
represented by multiple entries with the same keyword,
each specifying one value. Otherwise, there shall be at
most one entry for each attribute.
4. By default, entries may appear in any order. If there
are ordering constraints for particular entries, these
must be specified in their definitions.
5. The prtChannelInformation value may represent
information that is not normally coded in textual form,
or that is coded in a character set other than NVT
ASCII. In these cases, whatever symbolic representation
is conventionally used for the information should be
used for encoding the prtChannelInformation. (For
instance, a binary port value might be represented as a
decimal number, Unicode would be represented in UTF-8
format.)
6. For each PrtChannelType for which prtChannelInformation
entries are defined, the descriptive text associated
with the PrtChannelType enumeration value shall specify
the following information for each entry:
Title: Brief description phrase, e.g.: 'Port name,'Service
Name,'
Keyword: The keyword value, eg: 'Port,' 'Service' Syntax:
The encoding of the entry value, if it cannot be
directly represented by NVT ASCII,
Status: 'Mandatory,' 'Optional,' or 'Conditionally
Mandatory,'
Multiplicity: 'Single' or 'Multiple,' to indicate whether
the entry may be present multiple times,
Description: Description of the use of the entry, other
information required to complete the definition (e.g.:
ordering contstraints, interactions between entries).
Applications that interpret prtChannelInformation should ignore
unrecognized entries, so they are not affected if new entry
types are added.
Additional information:
After telling the peripheral how many logical channels will
be used, the IIO card tells the printer the value of the information
value of each of the channels. The information is auxiliary
information used in conjunction with the channel Type. |