Printronix P5005B, User Manual

Page: 17 / 366

Protocols And Emulations
17
Protocols And Emulations
A protocol is a set of rules governing the exchange of information
between the printer and its host computer. These rules consist of
codes that manipulate and print data and allow for machine-to-
machine communication. A printer and its host computer must use
the same protocol. As used in this manual, protocol and emulation
mean the same thing.
Most impact printers use single ASCII character codes to print text,
numbers, and punctuation marks. Some characters, both singly
and in groups of two or more, are defined as control codes. Control
codes instruct the printer to perform specific functions, such as
underlining text, printing subscripts, setting page margins, etc. The
main difference between most printer protocols is in the characters
used to create control codes and the ways in which these
characters are formatted.
When the printer executes the character and control codes of a
particular printer protocol, it is “emulating” that printer. If the printer
uses the Proprinter XL protocol, for example, it is emulating an
IBM
®
Proprinter XL printer. If the printer is using the Epson FX
printer protocol, for example, it is in Epson FX emulation mode.