Chapter 3: Programming the Printer 23Revision D 12/09
A799-PG00001D
Chapter 3: Programming the Printer
Overview of commands
Commands control all operations and functions of the printer. This includes selecting the size and placement of characters
and graphics on the receipt to feeding and cutting the paper. The programming commands have been organized, in order of
hexadecimal code within functional groups. For this reason, “related” commands may not be listed adjacent to one another.
The operation of various printers may be emulated by the commands, including the following:
• A793
• A794
• LEGACY
Any of the commands may be used in any combination to program a host computer to communicate with the printer
(unless otherwise noted).
Some commands listed and described here may not be implemented and are identied as “not implemented.” If received,
they are ignored and not sent to the print buffer as data.
Any nonlegal commands have their parameter sent to the print buffer as data.
Comparison to A793
The following table details the list of commands whose behavior differs between the A793, A794, and A799 because of the
physical differences of a 6 dots/mm head (A793) versus an 8 dots/mm head (A794 and A799).
Command Description Dierence between previous product
and new product emulation mode.
15 n Feed n dot rows This command will move the paper on the receipt in
n/203 inch steps instead of n/152 inch steps.
16 n Add n extra dot rows The dot rows will be measured in n/203 inches versus
n/152 inches.
1B 20 n Set right-side character spacing This command sets the right side spacing to “n” horizontal
motion units. By default, these units are in terms of 1/203
inches versus 1/152 inches.
1B 24 n1 n2 Set absolute starting position For graphics commands, the position is scaled to best
match A793. In text mode, the equivalent character
position is calculated.
1B 26 s c1 c2 n1 d1...nn dn] Dene user-dened character set Since the dots on the A799 printhead are smaller, user
dened characters that were used on the previous printers
will appear smaller on the A799 printer.
1B 2A m n1 n2 d1...dn Select bit image mode In A793 emulation mode, graphics are scaled to best
match the size of the graphic in the A793 printer.
1B 33 n Set line spacing This command uses n in terms of n/360 inches. Since the
A793 had a fundamental step of 1/152 inch and the A799
has a fundamental step of 1/203 inch, the actual line
spacing will not exactly match the requested spacing.
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