Lexmark FORMS 249X Technical Reference page 137

Creating the Character Data
Each dot-column is sent to the printer as three bytes of data. To get the values of
this data, convert the binary values to hexadecimal values.
First byte of data (most significant byte)
Second byte of data
Third byte of data (least significant byte)
The figure shows the hexadecimal value for each byte in each column of the
character. For example, the first byte of column one is binary 0011 1100 or 60,
x3C.
Compressing the Character
To make a compression mask, set the mask bit for each column (which is
identical to the column to its left) to one. Note that only 39 columns can be
compressed. The grid on page 136 shows that column 40 is the same as column
39; however, column 40 must be stored. Therefore, compression mask bit 40 is
set to zero.
Next, convert the binary values to hexadecimal. The compression mask for the
TM symbol is x2E74300002.
If you use compression, download only dot-columns with mask bits set to zero.
Data, with mask bits set to one, is generated by the printer according to the
compression mask.
Initializing the Download Area
Use the following command to initialize the download area:
<x
1B3D - download command prefix - initialize download area
0000 - byte count (low byte first) - 0
>
Top 8 print wires
Middle 8 print wires
Bottom 8 print wires
Section 7: Downloading Characters and Fonts
137