Printronix T5000R - Manual (Page 12)

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Chapter 2 The IPDS Emulation
The Data Towers
Most of the IPDS commands contain data fields. The type of data is
categorized into the following data towers:
Text The Presentation Text Object Content Architecture
(PTOCA) commands are a part of the text data tower.
This information is necessary to print text in a page, a
page segment, or an overlay.
IM Image The image data enables the printer to print images in a
page, a page segment, or an overlay.
IO Image This is not supported.
Graphics The Graphic Object Content Architecture (GOCA)
commands are a part of the graphics data tower. This
information is necessary to print images in a page, a
page segment, or an overlay.
Bar Code The Bar Code Object Content Architecture* (BCOCA*)
commands are a part of the bar code data tower. This
information is necessary to print bar codes in a page, a
page segment, or an overlay.
Some of the data towers contain only one level of commands; some contain
two.
PTOCA, GOCA, and BCOCA are described in more detail in the IBM
documentation.
The States
IPDS-capable printers are known as “state machines.” As the printer
recognizes a specific command, it operates in the state identified with that
command. Figure 1 shows the transition of the different states.
Home State The initial operating state. The printer returns to this state
after a page, an overlay, or a page segment has been
sent.
Block States The printer establishes the processing conditions for a
data block to be accepted. There are three block states:
IM image, graphics, and bar code.
Page State While printing a logical page, the printer is in the Page
State.
Overlay State This state permits overlay data blocks to be stored. An
overlay is a block of data that is frequently accessed. It
can be a block of text, images, graphics, or bar codes. An
overlay can be a predefined page or part of a page and is
often used for forms.