I suppose your USDA.ZPL file contain ZPL commands. As you can see here:
~DG and ^XG ZPL commands are intended to work with .GRF file format that can be produced by ZebraDesigner from .PCX file.
The ~DG command is to store .GRF file on printer and ^XG command to recall it from there and print.
Mentioned commands will not work with ZPL file stored on printer.
Working with Hex Graphic Images
ZPL II can be used to save graphic images in HEX format in DRAM, FLASH, or PCMCIA, depending
on the type of memory installed in your printer. ZPL II can be used to save graphic images in HEX
format in DRAM, FLASH, PCMCIA, or battery backed up SRAM, depending on the type of memory
installed in your printer. The image might be created using a CAD program, a draw or paint program,
or a scanner. These images can then be printed on the label. Graphic images may be created using
a program that creates files in the .PCX format. These files must then be converted to ZPL II graphic
format .GRF (pure hexadecimal data without headers or other extraneous information) for use as
part of a label format.
You can use ZebraDesigner or ZebraNet Bridge Enterprise to convert the .PCX graphic format into
the pure hexadecimal .GRF graphic format. Hexadecimal data may also be directly input as part of a
ZPL II program. Manually preparing a string of HEX code is possible but usually impractical.
Please, see here for details on how to work with hex graphic images:
Software Engineer, Kutir Mobility
Posted on behalf of Zebra Technologies