Printronix P3000 Series User's Reference Manual page 68

In Normal Density Plot:
The mode is selected with the odd dot plot control code ENQ (05 hex).
The odd–numbered dot columns are addressed to produce a horizontal and vertical density
that varies, based on the mode of operation:
Print Mode
Data Processing (DP)
Correspondence (NLQ)
High Speed (HS)
Barcode 145
Barcode 160
Different print modes cannot be mixed on the same dot row.
Figure 4–5 illustrates normal density dot plot.
In Double Density Plot:
Two separate shuttle strokes produce double density plot. First the even plot command
(EOT, 04 hex) and dot data are sent, followed by the odd plot command (ENQ, 05 hex) and
dot data, allowing a maximum of 1584 dots in a single dot row at 60 dpi.
Even dot plot is sent first for control of the initial plot pattern; then odd dot plot is sent for
control of the final dot pattern.
The dots average .017 inches in diameter.
The vertical density remains the same in normal and high density plotting.
Figure 4–6 illustrates double density plotting.
4–6
Horizontal dpi
60
90
60
72.5
80
Figure 4–5. Normal Density Plot
Figure 4–6. Double Density Plot
Vertical dpi
72
96
48
72
72
Graphics