Microcom 428T - Manual (Page 142)

Downloadable Graphics Chapter 6
6-6 428T Operator’s Manual - 880037-0141
8-bit data connections. This command is usable on data connections that support either 7
or 8-bit data.
The following is the format of the ^D104 command when used for a graphic image file:
^A<Slot Number>^D104
<Rotation> <Count> <Image Data>
Where:
<Memory Slot Number> is the memory slot location (1-255) where the graphic will be saved
in the printer’s memory. The printer uses the same TCI of “8” to select downloadable fonts
or graphics. Therefore a font and a graphic cannot have the same Slot Number or CGN
number.
<Rotation> is an 8-bit integer, 0 for an upright font, and 1 for a 90-degree rotated image.
<Count> is a 32-bit integer, least significant byte first. This is the number of bytes that the
image uses.
<Image Data> is the graphic image data that has been converted to ASCII-HEX.
ASCII-HEX Conversion
The ASCII-HEX conversion is performed by “ORing” the most significant and least
significant nibbles of every byte with “30” HEX.
For Example: To convert the byte “6C” to ASCII-HEX, simply OR the first and second
nibbles with “30” HEX. This results in the two bytes “36” HEX and “3C” HEX. This
conversion results in a file size that is twice as big as the source, the data can now be
transmitted over a 7-bit data connection.
Figure 6-1 ASCII-HEX Conversions
6.6 Graphic Image Data Format
The image data consists of a set of data structures and location offsets to those structures.
All data is stored in binary form. Multi-byte values are stored least-significant-byte first.
The method illustrated below allows graphic images to span 64KB memory segments.
When using graphics over 64KB, the printer will determine the number of 64KB slots
6C
6
C
36 3C