Printronix 9012 User's Reference Manual page 175

ESC + [n1n2] [data]
ESC +
n1n2
data
Appendix
The Serial Matrix Control Code Header introducing the Block
Transfer Header command.
n1 = The least significant byte of the block count;
n2 = The most significant byte of the block count.
where: n2 x 256 + n1 must be equal to or less than 2048.
The font descriptor data. Font descriptor data has 3 parts:
1. The character cell, which defines the font param-
ters;
2. The header word, which positions dot placement
within the character cell; and
3. The data words, which select/deselect the dots that
form the desired characters in the font.
The Character Cell
The seven character cell" parameters must be provided in the
first part of the first data block transferred. These parameters are
sent only once for the entire font being downloaded. These cell
parameters must be defined using the specific one-byte format
described below. Unused space within the cell (above and below
descending characters) and intercharacter spaces in the font ma
trix must also be identified.
nn Number of characters (values ranging from 1-255) in the
font.
ww Cell width. Cell width in columns must be a whole num
ber between 1 and 24.
hd Horizontal Density Code.
0 = 120 dpi
1 = 180 dpi
vd Vertical Density Code.
0 = 48 dpi
1 = 72 dpi
2 = 96 dpi
ur Number of uppercase rows (no descenders) n the charac
ter cell. The number of uppercase rows must be less than
or equal to the number of lowercase rows (lr).
lr Number of lowercase rows for descending characters.
The number of lowercase rows must be greater than or equal to
the number of uppercase rows (ur), but less than or equal to the
number of extended character rows (xr).
xr Number of rows in extended characters. The number of
extended character rows must be greater than or equal to the
number of lowercase rows (lr), but less than or equal to 16.
E-3