Digital Equipment LGplus Series, Руководство по установке

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Graphics Enhancement Options
The IGP/PGL and IGP/VGL Printronix emulations allow you to create and
store forms, generate logos, bar codes, expanded characters, and create other
graphics. Alphanumeric and bar code data are added as the form is printed.
These emulations are available as factory–installed or field–installed options.
For more information, contact your authorized Digital service representative.
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, we
can also say it is in Epson FX emulation mode.