The character arrangement table data following the header information is composed of the following components:

• A 256-byte translation table
• Four 2-byte fields for codes identifying character sets and their WCGM sequence numbers
• Four 4-byte fields for graphic character modification module names

The translation table consists of 256 one-byte entries, each pointing to one of 64 positions within one of four WCGMs:

• Bits 0 and 1 of each translation table byte refer to one of four WCGMs and bits 2 through 7 point to one of 64 addresses (0-63) within the WCGM. If SETPRT loads a character set into a WCGM other than the WCGM called for, SETPRT, using a copy of the translation table, alters bits 0 and 1 of each non-X'FF' byte of the translation table to correspond with the WCGM loaded. Figure 1 describes the structure of the character arrangement table module.
  Figure 1. Character Arrangement Table Module Structure

  
• A byte value of X'FF' indicates an unusable character, prints as a blank, and gives a data check. The data check is suppressed if the block data check option is selected.
• One translation table can address multiple WCGMs, and multiple translation tables can address one WCGM. The translation tables supplied by IBM address either one or two WCGMs.

The next two components provide the linkage to character sets and graphic character modification modules. They consist of four 2-byte fields containing character set IDs with their corresponding WCGM sequence numbers, followed by four 4-character names of graphic character modification modules. The format is as follows:

• Each CGMID is a 1-byte character set ID containing two hexadecimal digits that refer to a library character set (as listed in IBM 3800 Printing Subsystem Programmer's Guide ). Each WCGMNO refers to the corresponding WCGM sequence (X'00' to X'03'). Each name is the 4-character name of a graphic character modification module. Figure 2 shows the format of the Graphic Character Modification Modules.
  Figure 2. Graphic Character Modification Modules

  
• Most of the standard character arrangement tables do not need graphic character modification. The names are blank (X'40's) if no modules are referred to.
• The CGMIDx and the WCGMNOx are both X'00' when there are no character sets referred to after the first one.