Unitool can provide commands that enable or disable certain features of the printer. For the Kodak Diconix 150 Plus printer, the string ESCx3 defines the Select String command. In Unitool, ESCx3 is represented as \x1Bx\x03. The string ESC is replaced by the ASCII representation (\x1B), the argument x is not altered, and the decimal value 3 is replaced by the hexadecimal equivalent (\x03).
Commands can also contain parameters supplied by RasDD at runtime, when the command is used. For example, in the CURSORMOVE dialog box, the CM_OCD_YM_REL command advances the cursor in the positive y direction, relative to the current position. For the Diconix 150 plus printer, the Immediate Line Feed string, ESCJn defines the command, where n is the number of 1/288th inch increments that the cursor advances. In this case, the ESC string is replaced by its ASCII representation (\x1B), the argument J is not altered, and the variable n is replaced by the conversion character to convert the parameter to a byte value (%c).
Unitool stores each printer command in a CD data structure. In cases where RasDD supplies an argument to a particular command, such as the Immediate Line Feed command, Unitool stores the additional data in an Extended Command-Descriptor (EXTCD) data structure. This data structure contains values by which RasDD divides, multiplies, increases, or limits command arguments.