Specifying Channels

The CHANNELS section in the label_encodings file defines the lines that can appear below the PRINTER BANNER lines on the lower third of the banner and trailer pages. The CHANNELS section can be specified to print a string whenever the label of a print job contains a certain compartment.

Commercial sites can customize the text in the CHANNELS section with any compartment bit. Figure 4–7 shows a CHANNELS warning on a print job's banner page at a commercial site.

Figure 4.7. Commercial Use of CHANNELS on Banner Page

Commercial Use of CHANNELS on Banner Page

In U.S. government installations, the channels lines of the banner page conventionally show the warnings that are associated with the compartments of the job's label. Figure 4–8 shows a typical CHANNELS warning on a print job's banner page at a government installation: HANDLE VIA (CH B)/(CH A) CHANNELS JOINTLY.

The following discussion shows how the CHANNELS string HANDLE VIA (CH B)/(CH A) CHANNELS JOINTLY is specified for a job whose label includes the compartment words A and B. For the purpose of the example, only (CH A) and (CH B) apply. However, since the compartment bit for a third channel (CH C) is included in their definitions, (CH C) is also mentioned in this discussion.

The example illustrates these features:

Figure 4.8. U.S. Government Use of CHANNELS Specification on Banner Page

U.S. Government Use of CHANNELS Specification on Banner Page

As shown in the following example, two suffixes CHANNELS JOINTLY and CHANNELS ONLY and a prefix HANDLE VIA are defined.

Example 4.3. Suffixes and Prefixes in the CHANNELS Section in a Government label_encodings File

CHANNELS:

WORDS:
name= CHANNELS JOINTLY;         suffix;
name= CHANNELS ONLY;            suffix;
name= HANDLE VIA;               prefix;

After the prefixes and suffixes are defined as in Example 4–3, the channel names (CH A), (CH B), and (CH C) are specified in two different ways to achieve the following results:

Example 4.4.  CHANNELS ONLY Suffix That Appears Alone with Individual Channels

CHANNELS:

WORDS:

name= CHANNELS JOINTLY;         suffix;
name= CHANNELS ONLY;            suffix;
name= HANDLE VIA;               prefix;
name= (CH A);   prefix= HANDLE VIA; suffix= CHANNELS ONLY;
compartments= 0 ~1 ~6;
name= (CH B);   prefix= HANDLE VIA; suffix= CHANNELS ONLY;
compartments= ~0 1 ~6;
name= (CH C);   prefix= HANDLE VIA; suffix= CHANNELS ONLY;
compartments= ~0 ~1 6;

The first three lines of channel name definitions in the CHANNELS section that is shown in Example 4–4 have the following results:

Example 4.5. Encodings for More Than One Channel in CHANNELS Section in Government Encodings File

name= (CH A);   prefix= HANDLE VIA; suffix= CHANNELS ONLY; compartments= 0 ~1 ~6;
name= (CH B);   prefix= HANDLE VIA; suffix= CHANNELS ONLY; compartments= ~0 1 ~6;
name= (CH C);   prefix= HANDLE VIA; suffix= CHANNELS ONLY; compartments= ~0 ~1 6;

name= (CH C);   prefix= HANDLE VIA; suffix= CHANNELS JOINTLY; compartments= 6;
name= (CH B);   prefix= HANDLE VIA; suffix= CHANNELS JOINTLY; compartments= 1;
name= (CH A);   prefix= HANDLE VIA; suffix= CHANNELS JOINTLY; compartments= 0;

The CHANNELS specification in Example 4–5 illustrates the importance of order when compartments are being encoded. The first three lines handle the cases when only one of the channels compartment bits is turned on, so the last three lines can handle cases when more than one bit is turned. Therefore, none of the last three lines need to have any compartment bits explicitly set to 0. The result of these last three lines is that the suffix CHANNELS JOINTLY is always printed when any of two or more of the three compartment words that are associated with the channels is in the label.

The following example shows that compartment bit 6 is associated with the label word CC.

Example 4.6. Label WORDS Associated With Compartment Bit 6

SENSITIVITY LABELS:


WORDS:
  .
  .
  .
name= CC;                       minclass= TS; compartments= 6;

Example 4–7 shows that compartment bit 1 is associated with the sensitivity label word B.

Example 4.7. Label WORDS Associated With Compartment Bit 1

SENSITIVITY LABELS:

WORDS:
  .  .  .
name= B;                        minclass=  C; compartments= 1;

Example 4–8 shows that compartment bit 0 is associated with sensitivity label word A.

Example 4.8. Label WORDS Associated With Compartment Bit 0

SENSITIVITY LABELS:

WORDS:
   .   .   .
name= A;                        minclass=  C; compartments= 0;

To sum up, the channels line prints as HANDLE VIA (CH B)/(CH A) CHANNELS JOINTLY because of the following specifications:

For a sample CHANNELS planner, see Planning the Channels in a Worksheet.