HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part II

Glossary-4 EN
Downloading
The process of transferring soft fonts, macros, or raster data from a
host computer to the printer’s user memory is called downloading.
DTR Polarity
The configuration of DTR polarity determines whether pin 20, on the
serial interface connector, is high or low when the printer is ready. If
DTR polarity is HI, pin 20 is high when the printer is ready. If DTR
polarity is LO, pin 20 is low when the printer is ready.
Escape Character
The first character of a PCL command (or “escape sequence”) is
identified by the
? symbol, (ASCII decimal code 27). This character
is a control code used specifically by the printer to identify a string of
characters as a printer command. As the printer monitors incoming
data from a computer, it is “looking” for this character. When this
character appears, the printer reads it and its associated characters
as a command to be performed, and not data to be printed.
Escape Sequence (or “PCL Command”)
PCL escape sequences consist of two or more characters. The first
character is always the escape character, which is identified by the
?
symbol. This character is a control code used specifically by the
printer to identify a string of characters as a printer command. As the
printer monitors incoming data from a computer, it is “looking” for this
character. When this character appears, the printer reads it and its
associated characters as a command to be performed, and not as
data to be printed. (Also see PCL commands.)
Factory Default
These are the settings that are programmed into the printer at the
factory. These settings are in use unless you override them using
either the control panel or by sending printer commands.