The library character set data following the header information is a series of 73-byte segments for the 3800 Model 1 and 126-byte segments for the 3800 Model 3. Each module contains 64 segments. For each segment left undefined in a library character set module, IEBIMAGE inserts the graphic symbol for an undefined character. The structure of a library character set module is shown in Figure 1.

Figure 1. 3800 Model 3 Library Character Set Module Structure for One Character

A library character set is loaded directly into a WCGM. SETPRT uses the 6-bit code contained in the first byte of each 73-byte segment (for the 3800 Model 1) or 126-byte segment (for the 3800 Model 3) as the address of the WCGM location into which the remaining 72 bytes (for the 3800 Model 1) or 125 bytes (for the 3800 Model 3) are loaded.