The 3800 library character set module is a fixed-length module made up of 64 segments. Each segment contains the 73 bytes (for the 3800 Model 1) or 126 bytes (for the 3800 Model 3) of information including the scan pattern of a graphic character and a code (00-3F) that identifies the WCGM location into which the scan pattern is to be loaded.

The library character set module is created using the INCLUDE, CHARSET and NAME control statements.

The INCLUDE statement identifies an existing module.

The OPTION statement with the DEVICE parameter is required to create library character set modules in the 3800 Model 3 compatibility mode module format.

A CHARSET statement, when followed by one or more data statements, defines a user-designed character. A CHARSET statement can also select a character segment from another library character set or from a graphic character modification module.

The NAME statement specifies the ID of the character set being created and indicates if it is to replace an existing module. More than one CHARSET statement can be coded between the INCLUDE and NAME statements; all such CHARSET statements apply to the same library character set module.